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Bob Marcus
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

Darryl Miyaguchi wrote in message ...

For what it's worth, I have performed enough ABX testing to convince
myself that it's possible for me to detect volume differences 0.5 dB
using music, so I doubt very highly that a group test would fail to
show that 1.75 dB differences on a variety of different music are not
audible using a DBT.

I think it's generally acknowledged that such differences are audible.
Mirabel seems to be arguing that, given what he claims is a 1.75 dB
difference, every member of Greenhill's panel should have scored at
or near perfection, and the fact that they didn't bespeaks some flaw
in Greenhill's methodology.

I'm not yet convinced that there really was a 1.75 dB difference here,
however. What Greenhill says about the 24-gauge cable is:

"Its 1.8-ohm resistance resulted in a 1.76-dB insertion loss with an
8-ohm resistive load."

How does this translate to the specific test in question, which used a
recording of a male a cappella chorus (where the fundamental tones, at
least, range from 60 to less than 1000 Hz)?

Greenhill only level-matched a single pink noise test, and the only
times he discusses levels in the article appear to be in reference to
pink noise tests. E.g.:

"A 1- to 2-dB decrease in sound level was measured for the 24-gauge
wire during the pink noise listening tests."

I freely admit that I'm out of my element here, but I don't think we
can automatically assume that there was a similar difference in SPL
when listening to the choral music.

Hopefully, someone with some technical expertise can shed some further
light on this.

bob
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Arny Krueger
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

"ludovic mirabel" wrote in message
news:uCJLa.56660$Ab2.130013@sccrnsc01

(KikeG) wrote in message
et...


(ludovic mirabel) wrote in message
news:bn2La.36126$Ab2.61637@sccrnsc01...

I haven't read Greenhill's tests report, but it seems there's some
controversy over what you are saying. Even if that was true, that
would suggest there were some problems at the test, since anyone of
my family could ABX that wideband level difference quite easily.


Enrique (Kike For friends)


Apologies for dealing just with this for the time being . It concerns
intellectual honesty something I happen to be touchy about.
The " Cable test's (" Stereo Review",Aug. '83) proctor and reporter
was immaculately "objectivist" L. Greenhill- still alive and writing
for "The Stereophile"


Looking at the calendar, I see that in two months it will be 20 years since
this test was published. Considering editing and publishing delays, it's
already been 20 years since the test was done. If this were the only test
that was done in the history of man, or if every other or the vast majority
of DBTs that were done since then agreed with its results, then citing it
would make some sense. Regrettably, DBTs and even ABX tests involving level
differences have been done many times since then, and very many of those
listening tests have provided far more sensitive results.

Therefore, discussion of Greenhill's 1983 test as if it were indicative,
representative or binding on what's happening today is futile and
misleading.

Anybody who wishes to do DBTs to investigate the audibility of level
differences can do so easily using files they can freely download from the
PCABX web site. I think it would be interesting for people to report the
results they obtain with those files.

IME the audibility of level differences for people with normal hearing and
typical listening environments is closer to 0.5 dB than the 1.75 dB reported
by Greenhill.

Since individual listeners have different test environments and different
ears, their results can be reasonably be expected to vary.

In fact if the results didn't vary, it would suggest that there is
something wrong with the test procedure since it would not be demonstrating
the existence of well-known differences in individual listening acuity.
However, it is equally well known that some place around level differences
of 0.2 dB, nobody hears nuttin'.

  #3   Report Post  
Darryl Miyaguchi
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

On 1 Jul 2003 15:10:59 GMT, (ludovic mirabel)
wrote:

We're talking about Greenhill old test not because it is perfect but
because no better COMPONENT COMPARISON tests are available. In fact
none have been published according to MTry's and Ramplemann's
bibliographies since 1990.


I frequently see the distinction being made between audio components
and other audio related things (such as codecs) when it comes to
talking about DBT's. What is the reason for this?

In my opinion, there are two topics which should not be mixed up:

1) The effectiveness of DBT's for determining whether an audible
difference exists
2) The practical usefulness of using DBT's for choosing one audio
producer (component or codec) over another.

I am not knowledgeable enough to decide on differences between
your and Greenhill's interpretation of the methods and results.
In my simplistic way I'd ask you to consider the following:
PINK NOISE signal: 10 out of 11 participants got the maximum possible
correct answers: 15 out of 15 ie. 100%. ONE was 1 guess short. He got
only 14 out of 15.
When MUSIC was used as a signal 1 (ONE) listener got 15 corrects,
1 got 14 and one 12. The others had results ranging from 7 and 8
through 10 to (1) 11.
My question is: was there are ANY significant difference between
those two sets of results? Is there a *possibility* that music
disagrees with ABX or ABX with music?


Even between two samples of music (no pink noise involved), I can
certainly believe that a listening panel might have more or less
difficulty in determining if they hear an audible difference. It
doesn't follow that music in general is interfering with the ability
to discriminate differences when using a DBT.

I would aoppreciate it if would try and make it simple leaving
"confidence levels" and such out of it. You're talking to ordinary
audiophiles wanting to hear if your test will help them decide what
COMPONENTS to buy.


See my first comments. It's too easy to mix up the topic of the
sensitivity of DBT's as instruments for detecting audible differences
with the topic of the practicality of using DBT's to choose hifi
hardware. The latter is impractical for the average audiophile.

Who can argue with motherhood? The problem is that there are NO
ABX COMPONENT tests being published- neither better nor worse, NONE.
I heard of several audio societies considering them. No results.
Not from the objectivist citadels: Detroit and Boston. Why?. Did they
pan out?


I can think of a couple of reasons:

1. It's expensive and time consuming to perfom this type of testing
2. The audible differences are, in actuality, too subtle to hear, ABX
or not. Why bother with such a test?

Then there is the possibility that you seem to be focussing on,
ignoring the above two:

3. DBT's in general may be decreasing the ability to hear subtle
differences.

Which of the the above reaons do you think are most likely?

Moving away from the question Greenhill was investigating

(audible
differences between cables) and focusing only on DBT testing and
volume differences: it is trivial to perform a test of volume
difference, if the contention is being made that a DBT hinders the
listener from detecting 1.75 dB of volume difference. Especially if
the listeners have been trained specifically for detecting volume
differences prior to the test.
However, such an experiment would be exceedingly uninteresting, and I
have doubts it would sway the opinion of anybody participating in this
debate.

The volume difference was just a by-effect of a comparison between
cables.
And yes, TRAINED people would do better than Greenhill's "Expert
audiophiles" ie rank amateurs just like us. Would some though do
better than the others and some remain untrainable? Just like us.


I have no doubt that there are some people who are unreliable when it
comes to performing a DBT test. In a codec test using ABC/HR, if
somebody rates the hidden reference worse than the revealed reference
(both references are identical), his listening opinion is either
weighted less or thrown out altogether.

For what it's worth, I have performed enough ABX testing to convince
myself that it's possible for me to detect volume differences 0.5 dB
using music, so I doubt very highly that a group test would fail to
show that 1.75 dB differences on a variety of different music are not
audible using a DBT.

I can easily hear 1db difference between channels, and a change
of 1 db.
What I can't do is to have 80 db changed to 81 db, then be asked if
the third unknown is 80 or 81 dbs. and be consistently correct.
Perhaps I could if I trained as much as you have done. Perhaps not
Some others could, some couldn't. We're all different. Produce a test
which will be valid for all ages, genders, extent of training, innate
musical and ABxing abilities, all kinds of musical experience and
preference. Then prove BY EXPERIMENT that it works for COMPARING
COMPONENTS.
So that anyone can do it and if he gets a null result BE CERTAIN that
with more training or different musical experience he would not hear
what he did not hear before. And perhaps just get on widening his
musical experience and then rcompare (with his eyes covered if he is
marketing susceptible)
Let's keep it simple. We're audiophiles here. We're talking about
MUSICAL REPRODUCTION DIFFERENCES between AUDIO COMPONENTS. I looked
at your internet graphs. They mean zero to me. I know M. Levinsohn,
Quad, Apogee, Acoustat not the names of your codecs. You assure me
that they are relevant. Perhaps. Let's see BY EXPERIMENT if they do.
In the meantime enjoy your lab work.
Ludovic Mirabel


Are you really telling me that you didn't understand the gist of the
group listening test I pointed you to?

For one thing, it says that although people have different individual
preferences about how they evaluate codec quality, as a group, they
can identify trends. This, despite the variety of training, hearing
acuity, audio equipment, and listening environment.

Another point is that it would be more difficult to identify trends if
such a study included the opinions of people who judge the hidden
reference to be worse than the revealed reference (simultaneously
judging the encoded signal to be the same as the revealed reference).
In other words, there are people whose listening opinions can't be
trusted, and the DBT is designed to identify them.

The last point is that I can see no reason why such procedures could
not (in theory, if perhaps not in practical terms) be applied to audio
components. Why don't you explain to me what the difference is (in
terms of sensitivity) between using DBT's for audio codecs and using
DBT's for audio components?

Darryl Miyaguchi
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Darryl Miyaguchi
 
Posts: n/a
Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

On 1 Jul 2003 15:10:59 GMT, (ludovic mirabel)
wrote:

We're talking about Greenhill old test not because it is perfect but
because no better COMPONENT COMPARISON tests are available. In fact
none have been published according to MTry's and Ramplemann's
bibliographies since 1990.


I frequently see the distinction being made between audio components
and other audio related things (such as codecs) when it comes to
talking about DBT's. What is the reason for this?

In my opinion, there are two topics which should not be mixed up:

1) The effectiveness of DBT's for determining whether an audible
difference exists
2) The practical usefulness of using DBT's for choosing one audio
producer (component or codec) over another.

I am not knowledgeable enough to decide on differences between
your and Greenhill's interpretation of the methods and results.
In my simplistic way I'd ask you to consider the following:
PINK NOISE signal: 10 out of 11 participants got the maximum possible
correct answers: 15 out of 15 ie. 100%. ONE was 1 guess short. He got
only 14 out of 15.
When MUSIC was used as a signal 1 (ONE) listener got 15 corrects,
1 got 14 and one 12. The others had results ranging from 7 and 8
through 10 to (1) 11.
My question is: was there are ANY significant difference between
those two sets of results? Is there a *possibility* that music
disagrees with ABX or ABX with music?


Even between two samples of music (no pink noise involved), I can
certainly believe that a listening panel might have more or less
difficulty in determining if they hear an audible difference. It
doesn't follow that music in general is interfering with the ability
to discriminate differences when using a DBT.

I would aoppreciate it if would try and make it simple leaving
"confidence levels" and such out of it. You're talking to ordinary
audiophiles wanting to hear if your test will help them decide what
COMPONENTS to buy.


See my first comments. It's too easy to mix up the topic of the
sensitivity of DBT's as instruments for detecting audible differences
with the topic of the practicality of using DBT's to choose hifi
hardware. The latter is impractical for the average audiophile.

Who can argue with motherhood? The problem is that there are NO
ABX COMPONENT tests being published- neither better nor worse, NONE.
I heard of several audio societies considering them. No results.
Not from the objectivist citadels: Detroit and Boston. Why?. Did they
pan out?


I can think of a couple of reasons:

1. It's expensive and time consuming to perfom this type of testing
2. The audible differences are, in actuality, too subtle to hear, ABX
or not. Why bother with such a test?

Then there is the possibility that you seem to be focussing on,
ignoring the above two:

3. DBT's in general may be decreasing the ability to hear subtle
differences.

Which of the the above reaons do you think are most likely?

Moving away from the question Greenhill was investigating

(audible
differences between cables) and focusing only on DBT testing and
volume differences: it is trivial to perform a test of volume
difference, if the contention is being made that a DBT hinders the
listener from detecting 1.75 dB of volume difference. Especially if
the listeners have been trained specifically for detecting volume
differences prior to the test.
However, such an experiment would be exceedingly uninteresting, and I
have doubts it would sway the opinion of anybody participating in this
debate.

The volume difference was just a by-effect of a comparison between
cables.
And yes, TRAINED people would do better than Greenhill's "Expert
audiophiles" ie rank amateurs just like us. Would some though do
better than the others and some remain untrainable? Just like us.


I have no doubt that there are some people who are unreliable when it
comes to performing a DBT test. In a codec test using ABC/HR, if
somebody rates the hidden reference worse than the revealed reference
(both references are identical), his listening opinion is either
weighted less or thrown out altogether.

For what it's worth, I have performed enough ABX testing to convince
myself that it's possible for me to detect volume differences 0.5 dB
using music, so I doubt very highly that a group test would fail to
show that 1.75 dB differences on a variety of different music are not
audible using a DBT.

I can easily hear 1db difference between channels, and a change
of 1 db.
What I can't do is to have 80 db changed to 81 db, then be asked if
the third unknown is 80 or 81 dbs. and be consistently correct.
Perhaps I could if I trained as much as you have done. Perhaps not
Some others could, some couldn't. We're all different. Produce a test
which will be valid for all ages, genders, extent of training, innate
musical and ABxing abilities, all kinds of musical experience and
preference. Then prove BY EXPERIMENT that it works for COMPARING
COMPONENTS.
So that anyone can do it and if he gets a null result BE CERTAIN that
with more training or different musical experience he would not hear
what he did not hear before. And perhaps just get on widening his
musical experience and then rcompare (with his eyes covered if he is
marketing susceptible)
Let's keep it simple. We're audiophiles here. We're talking about
MUSICAL REPRODUCTION DIFFERENCES between AUDIO COMPONENTS. I looked
at your internet graphs. They mean zero to me. I know M. Levinsohn,
Quad, Apogee, Acoustat not the names of your codecs. You assure me
that they are relevant. Perhaps. Let's see BY EXPERIMENT if they do.
In the meantime enjoy your lab work.
Ludovic Mirabel


Are you really telling me that you didn't understand the gist of the
group listening test I pointed you to?

For one thing, it says that although people have different individual
preferences about how they evaluate codec quality, as a group, they
can identify trends. This, despite the variety of training, hearing
acuity, audio equipment, and listening environment.

Another point is that it would be more difficult to identify trends if
such a study included the opinions of people who judge the hidden
reference to be worse than the revealed reference (simultaneously
judging the encoded signal to be the same as the revealed reference).
In other words, there are people whose listening opinions can't be
trusted, and the DBT is designed to identify them.

The last point is that I can see no reason why such procedures could
not (in theory, if perhaps not in practical terms) be applied to audio
components. Why don't you explain to me what the difference is (in
terms of sensitivity) between using DBT's for audio codecs and using
DBT's for audio components?

Darryl Miyaguchi
  #5   Report Post  
Bob Marcus
 
Posts: n/a
Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

(ludovic mirabel) wrote in message ...

PINK NOISE signal: 10 out of 11 participants got the maximum possible
correct answers: 15 out of 15 ie. 100%. ONE was 1 guess short. He got
only 14 out of 15.
When MUSIC was used as a signal 1 (ONE) listener got 15 corrects,
1 got 14 and one 12. The others had results ranging from 7 and 8
through 10 to (1) 11.
My question is: was there are ANY significant difference between
those two sets of results? Is there a *possibility* that music
disagrees with ABX or ABX with music?


I suspect a major reason it's more difficult to hear level differences
in music is that the actual level is constantly changing. But of
course this effect wouldn't be limited to listening in ABX tests. It
would be harder to discern level differences in *any* comparison
involving music.

snip?

The problem is that there are NO
ABX COMPONENT tests being published- neither better nor worse, NONE.


Possible explanations for this:

1) People did further tests, but didn't get them published because
they arrived at the same result, and no one publishes "old news."

2) People stopped trying because they had no reason to believe they
*would* get different results.

snip

I can easily hear 1db difference between channels, and a change
of 1 db.
What I can't do is to have 80 db changed to 81 db, then be asked if
the third unknown is 80 or 81 dbs. and be consistently correct.


Two questions:

1) What do you mean by "consistent"? 100% of the time, or just with
statistical reliability?

2) Were you able to switch instantaneously between them? Audiophiles
pooh-pooh this, but it's certainly easier to hear level differences
when you can switch instantaneously.

Perhaps I could if I trained as much as you have done. Perhaps not
Some others could, some couldn't. We're all different. Produce a test
which will be valid for all ages, genders, extent of training, innate
musical and ABxing abilities, all kinds of musical experience and
preference.


You're assuming that if you can't hear a difference that some other
people can hear, then the test isn't right for you. But maybe you just
can't hear that difference. As you say, we are all different.

Then prove BY EXPERIMENT that it works for COMPARING
COMPONENTS.


How would you prove such a thing?

So that anyone can do it and if he gets a null result BE CERTAIN that
with more training or different musical experience he would not hear
what he did not hear before.


The only way to be certain of this would be to train himself, and then
take the test again. OTOH, if there is no documented case of anyone
ever hearing such a difference, it might be a waste of time to try to
find out if you are the exception.

And perhaps just get on widening his
musical experience


I'm not aware of any evidence that musical experience is particularly
helpful in these kinds of tests. That's not what "training" is about
in this context.

and then rcompare (with his eyes covered if he is
marketing susceptible)


If??? Everyone is susceptible to sighted bias (which has nothing
necessarily to do with "marketing").

Let's keep it simple. We're audiophiles here. We're talking about
MUSICAL REPRODUCTION DIFFERENCES between AUDIO COMPONENTS. I looked
at your internet graphs. They mean zero to me. I know M. Levinsohn,
Quad, Apogee, Acoustat not the names of your codecs. You assure me
that they are relevant. Perhaps. Let's see BY EXPERIMENT if they do.


So far as I can tell, the only experiment that would satisfy you would
be one that confirmed your own beliefs about what is and is not
audible. I'm afraid we can't do that.

bob


  #6   Report Post  
Steven Sullivan
 
Posts: n/a
Default Why DBTs in audio do not deliver

Darryl Miyaguchi wrote:
Let's keep it simple. We're audiophiles here. We're talking about
MUSICAL REPRODUCTION DIFFERENCES between AUDIO COMPONENTS. I looked
at your internet graphs. They mean zero to me. I know M. Levinsohn,
Quad, Apogee, Acoustat not the names of your codecs. You assure me
that they are relevant. Perhaps. Let's see BY EXPERIMENT if they do.
In the meantime enjoy your lab work.
Ludovic Mirabel


Are you really telling me that you didn't understand the gist of the
group listening test I pointed you to?


Whether he realizes it or not, he's telling you *he* doesn't comprehend them.

--
-S.
  #7   Report Post  
Nousaine
 
Posts: n/a
Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

Darryl Miyaguchi
wrote:

In some parts I will reply to the post to which Mr Miyaguch is replying:

On 1 Jul 2003 15:10:59 GMT,
(ludovic mirabel)
wrote:

We're talking about Greenhill old test not because it is perfect but
because no better COMPONENT COMPARISON tests are available. In fact
none have been published according to MTry's and Ramplemann's
bibliographies since 1990.


This is simply not true. I have published 2 double blind tests personally, one
of which covered 3 different wires subsequent to 1990.


I frequently see the distinction being made between audio components
and other audio related things (such as codecs) when it comes to
talking about DBT's. What is the reason for this?

In my opinion, there are two topics which should not be mixed up:

1) The effectiveness of DBT's for determining whether an audible
difference exists
2) The practical usefulness of using DBT's for choosing one audio
producer (component or codec) over another.


Actually if nominally competent components such as wires, parts, bits and
amplifiers have never been shown to materially affect the sound of reproduced
music in normally reverberant conditions why would ANYONE need to conduct more
experimentation, or any listening test, to choose between components? Simply
choose the one with the other non-sonic characteristics (features, price,
terms, availability, cosmetics, style...) that suit your fancy.

Indeed 20 years ago, when I still had a day job, Radio Shack often had the
"perfect" characteristic to guide purchase, which was "open on Sunday."
I am not knowledgeable enough to decide on differences between
your and Greenhill's interpretation of the methods and results.
In my simplistic way I'd ask you to consider the following:
PINK NOISE signal: 10 out of 11 participants got the maximum possible
correct answers: 15 out of 15 ie. 100%. ONE was 1 guess short. He got
only 14 out of 15.
When MUSIC was used as a signal 1 (ONE) listener got 15 corrects,
1 got 14 and one 12. The others had results ranging from 7 and 8
through 10 to (1) 11.
My question is: was there are ANY significant difference between
those two sets of results? Is there a *possibility* that music
disagrees with ABX or ABX with music?


No: it just means with the right set of music 2 dB is at the threshold. Don't
forget that listening position affects this stuff too. Also Mr Atkinson would
say that perhaps the lower scoring subjects didn't have personal control of the
switching.

Even between two samples of music (no pink noise involved), I can
certainly believe that a listening panel might have more or less
difficulty in determining if they hear an audible difference. It
doesn't follow that music in general is interfering with the ability
to discriminate differences when using a DBT.


Actually it simp,y shows that pink noise and other test signals are the most
sensitive of programs. It may be possible to divulge a 'difference' with noise
that would never be encountered with any known program material.

It's also possible that certain programs, such as Arny Kreuger's special
signals, might disclose differences that may never be encountered with
commercially available music (or other) programs. So?

I would aoppreciate it if would try and make it simple leaving
"confidence levels" and such out of it. You're talking to ordinary
audiophiles wanting to hear if your test will help them decide what
COMPONENTS to buy.


As before; you haven't ever been precluded from making any purchase decisions
from scientific evidence before; why should any disclosure affect that now or
in the future.

Examination of the extant body of controlled listening tests available contain
enough information to aid any enthusiast in making good decisions. Even IF the
existing evidence shows that wire is wire (and it does) how does that preclude
any person from making any purchase decision? In my way of thinking it just
might be useful for a given individual to know what has gone before (and what
hasn't.)

I still don't know how this cannot do anything but IMPROVE decision making?

See my first comments. It's too easy to mix up the topic of the
sensitivity of DBT's as instruments for detecting audible differences
with the topic of the practicality of using DBT's to choose hifi
hardware. The latter is impractical for the average audiophile.


No it's not. Just like 0-60 times, skid-pad and EPA mileage tests simply cannot
be made by the typical individual that doesn't mean that they cannot be used to
improve decision-making. Likewise the body of controlled listening test results
can be very useful to any individual that wishes to make use of them to guide
decisions.

Otherwise the only information one has is "guidance" from sellers, anecdotal
reports and "open" listening tests. The latter , of course, is quite subject to
non-sonic influence.

So IMO, a person truly interested in maximizing the sonic-quality throughput of
his system simply MUST examine the results of bias controlled listening tests
OR fall prey to non-sonic biasing factors, even if they are inadvertent.


Who can argue with motherhood? The problem is that there are NO
ABX COMPONENT tests being published- neither better nor worse, NONE.
I heard of several audio societies considering them. No results.
Not from the objectivist citadels: Detroit and Boston. Why?. Did they
pan out?


Given the two dozen controlled listening tests of power amplifiers published
through 1991 doesn't it seem that no one needs to conduct more? Wires? The last
test I published was in 1995. Not late enough?

Why not? No manufacturer has EVER produced a single bias controlled experiment
that showed their wires had a sound of their own in over 30 years. Why should
one expect one now?

I certainly can't do it; although I've given it my level (no pun intended)
best. IOW, I can't produce an experiment that shows nominally competent wires
ain't wires .... 'cuz they ain't.

I can think of a couple of reasons:

1. It's expensive and time consuming to perfom this type of testing
2. The audible differences are, in actuality, too subtle to hear, ABX
or not. Why bother with such a test?


Why bother in performing a sound quality "test" that the manufacturers of the
equipment can't produce? IF amps ain't amps; wires ain't wires and parts ain't
parts then why haven't the makers and sellers of this stuff produced repeatable
bias controlled listening tests that show this to be untrue?

Then there is the possibility that you seem to be focussing on,
ignoring the above two:

3. DBT's in general may be decreasing the ability to hear subtle
differences.


Actually they preclude the ability to "hear" non-sonic differences.

Which of the the above reaons do you think are most likely?

Moving away from the question Greenhill was investigating

(audible
differences between cables) and focusing only on DBT testing and
volume differences: it is trivial to perform a test of volume
difference, if the contention is being made that a DBT hinders the
listener from detecting 1.75 dB of volume difference. Especially if
the listeners have been trained specifically for detecting volume
differences prior to the test.
However, such an experiment would be exceedingly uninteresting, and I
have doubts it would sway the opinion of anybody participating in this
debate.

The volume difference was just a by-effect of a comparison between
cables.
And yes, TRAINED people would do better than Greenhill's "Expert
audiophiles" ie rank amateurs just like us. Would some though do
better than the others and some remain untrainable? Just like us.


I think Ludovic is "untrainable" because he will accept only answers he already
believes are true.

I have no doubt that there are some people who are unreliable when it
comes to performing a DBT test. In a codec test using ABC/HR, if
somebody rates the hidden reference worse than the revealed reference
(both references are identical), his listening opinion is either
weighted less or thrown out altogether.


What you are describing is 'reverse significance' which is typically a
inadvertant form of internal bias.

For what it's worth, I have performed enough ABX testing to convince
myself that it's possible for me to detect volume differences 0.5 dB
using music, so I doubt very highly that a group test would fail to
show that 1.75 dB differences on a variety of different music are not
audible using a DBT.

I can easily hear 1db difference between channels, and a change
of 1 db.
What I can't do is to have 80 db changed to 81 db, then be asked if
the third unknown is 80 or 81 dbs. and be consistently correct.
Perhaps I could if I trained as much as you have done. Perhaps not
Some others could, some couldn't. We're all different. Produce a test
which will be valid for all ages, genders, extent of training, innate
musical and ABxing abilities, all kinds of musical experience and
preference. Then prove BY EXPERIMENT that it works for COMPARING
COMPONENTS.
So that anyone can do it and if he gets a null result BE CERTAIN that
with more training or different musical experience he would not hear
what he did not hear before. And perhaps just get on widening his
musical experience and then rcompare (with his eyes covered if he is
marketing susceptible)
Let's keep it simple. We're audiophiles here. We're talking about
MUSICAL REPRODUCTION DIFFERENCES between AUDIO COMPONENTS. I looked
at your internet graphs. They mean zero to me. I know M. Levinsohn,
Quad, Apogee, Acoustat not the names of your codecs. You assure me
that they are relevant. Perhaps. Let's see BY EXPERIMENT if they do.
In the meantime enjoy your lab work.
Ludovic Mirabel


Are you really telling me that you didn't understand the gist of the
group listening test I pointed you to?

For one thing, it says that although people have different individual
preferences about how they evaluate codec quality, as a group, they
can identify trends. This, despite the variety of training, hearing
acuity, audio equipment, and listening environment.

Another point is that it would be more difficult to identify trends if
such a study included the opinions of people who judge the hidden
reference to be worse than the revealed reference (simultaneously
judging the encoded signal to be the same as the revealed reference).
In other words, there are people whose listening opinions can't be
trusted, and the DBT is designed to identify them.


That result identifies a form of experimental bias, does it not?

The last point is that I can see no reason why such procedures could
not (in theory, if perhaps not in practical terms) be applied to audio
components. Why don't you explain to me what the difference is (in
terms of sensitivity) between using DBT's for audio codecs and using
DBT's for audio components?

Darryl Miyaguchi


There is no difference. It seems to me that this poster may have never taken a
bias controlled listening test or, if he has, the results didn't fit with prior
held expectations. It's much easier to argue with the existing evidence than
prove that you can hear things that no human has been able to demonstrate, when
not peeking.

As I've said before; there are many proponents of high-end sound of wires, amps
and parts ... but, so far, no one (in over 30 years) has ever produced a single
repeatable bias controlled experiment that shows that nominally competent
products in a normally reverberant environment (listening room) have any sonic
contribution of their own.

Nobody! Never! How about some evidence? I'll believe in BigFoot ....just show
me the body!
  #8   Report Post  
KikeG
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

(ludovic mirabel) wrote in message ...

We're talking about Greenhill old test not because it is perfect but
because no better COMPONENT COMPARISON tests are available. In fact
none have been published according to MTry's and Ramplemann's
bibliographies since 1990.


I gave a link to one at my previous message, related to soundcards and
a DAT (
http://www.hydrogenaudio.org/index.p...hl=pitch&st=0&
). It revealed some audible differences. Soundcards and DATs are audio
components, aren't they?

There's another one concerning just a soundcard he
http://www.hydrogenaudio.org/index.p...d6a76f1f8d0738
It finally revealed no audible differences.

About Greenhill's test and level differences:

PINK NOISE signal: 10 out of 11 participants got the maximum possible
correct answers: 15 out of 15 ie. 100%. ONE was 1 guess short. He got
only 14 out of 15.
When MUSIC was used as a signal 1 (ONE) listener got 15 corrects,
1 got 14 and one 12. The others had results ranging from 7 and 8
through 10 to (1) 11.
My question is: was there are ANY significant difference between
those two sets of results? Is there a *possibility* that music
disagrees with ABX or ABX with music?
I would aoppreciate it if would try and make it simple leaving
"confidence levels" and such out of it. You're talking to ordinary
audiophiles wanting to hear if your test will help them decide what
COMPONENTS to buy.


Citing Greenhill's article, refering to 24-gauge cable: "Its 1.8-ohm
resistance resulted in a 1.76-dB insertion loss with an 8-ohm
resistive load".

I don't know if this has been addressed before, but this 1.76 dB loss
corresponds to a pure resistive load. Speakers are quite different
from pure resistive loads, in the sense that their impedance varies
with frequency, being this impedance higher than the nominal in most
part of the spectrum. So, this 1.8 ohm in series with a real world
speaker would definitely result in an attenuation below 1.76 dB over
the whole audible spectrum on a wideband signal. Also, the attenuation
will vary with frequency, so that max attenuation will be at the
frequencies where the speaker impedance is minimum, and there will be
little attenuation at frequencies where speaker impedance is maximum.
So, the whole attenuation will depend on the spectrum of music used.
There's a possibility that choral music has most of its content at
frequencies where attenuation was not high, but it's difficult to know
without having access to the actual music used and the speaker
impedance curve.

Said, that, I tried yesterday to ABX an 1.7 dB wideband (frequency
constant) level attenuation on a musical sample. Result: 60/60 on a
couple of minutes, Not a single miss. It is obvious to hear, but one
could argue I'm trained.

Despite that, I claim that, any person that does not have serious
auditive problems, would be able to ABX a 1.7 dB wideband level
difference on any kind of real-world music, being trained or not in
ABX testing, just taking a couple of minutes to explain him the basics
of ABX testing.

Now, you make a point in that you have to be trained in ABXing to be
good at it. I say that you have to be trained in *any* method you use
to be good at it. Also, ABX testing per se requires little training.
What takes more training is to learn to detect reliabily some kind of
differences, whether you use ABX or not. Serious ABX training is
required just for detecting very subtle differences, just like in
every other area where high performance is required.

And finally, an analogy: you can't evaluate driving comfort in cars
without driving them, so you have to learn how to drive in order to
evaluate driving comfort. Driving a car is the only reliable way to
evaluate driving confort, whether you are good at it or not. And
such...
  #10   Report Post  
S888Wheel
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

Tom said


Actually if nominally competent components such as wires, parts, bits and
amplifiers have never been shown to materially affect the sound of reproduced
music in normally reverberant conditions why would ANYONE need to conduct
more
experimentation, or any listening test, to choose between components? Simply
choose the one with the other non-sonic characteristics (features, price,
terms, availability, cosmetics, style...) that suit your fancy.


That is the 64,000 dollar if.

Tom said


Examination of the extant body of controlled listening tests available
contain
enough information to aid any enthusiast in making good decisions. Even IF
the
existing evidence shows that wire is wire (and it does) how does that
preclude
any person from making any purchase decision? In my way of thinking it just
might be useful for a given individual to know what has gone before (and what
hasn't.)


Well, so far I don't see it the way you do. I must at this point thanl you for
the articles on this subject you sent me when I asked for the alleged body of
empirical evidence that prooved your position on the audible differences of
amplifiers. The "body of evidence" you sent me that constituted actual
evidence, raw data, was not much of a body. Only two articles out of the six
you sent had raw data ( "Can you trust your ears" by Tom Nousiane and "Do all
amplifiers sound the same" by David Clark) and only the test you conducted had
it in a usful table which could allow for the examination of trends such as
learning curves or fatigue curves. First, this is not much of a body of
evidence. Second, if we are to draw conclusions from the results we would have
to conclude that some people can hear differences between amps and some amps
sound idfferent than some other amps. Of course it would be a mistake to draw
conclusions from those tests by themselves because they simply are not that
conclusive. If what you sent me is the best evidence out there and if what you
sent me is any significant portion of the much talked about "extant body of
controled listening tests available" then I don't see how anyone can draw any
strong conclusions one way or another.

Tom said


So IMO, a person truly interested in maximizing the sonic-quality throughput
of
his system simply MUST examine the results of bias controlled listening tests
OR fall prey to non-sonic biasing factors, even if they are inadvertent.


I examined the results of contained in the articles you sent me and do not
find them conclusive. Unfortunately four of the six articles you sent me had no
raw data to examine and only offered conclusions. Given the fact that the two
articles that did offer raw data drew conclusions that I find questionable i
have trouble feeling condifent about the conclusions drawn in the other
articles missing the raw data. So I find the evidence to date that I have seen
less than helpful in purchase decisions.


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ludovic mirabel
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

(Nousaine) wrote in message ...


See his full text below:
On 1 Jul 2003 15:10:59 GMT,
(ludovic mirabel)
wrote:
_ I can't possibly answer separately and in detail all those disagreeing with me I have to live whatever remains to me of life.In particular I'll not get in between Mrs. Miyaguchi and Nousaine in the subargument of their own.

So 4 interactive complementary answers for economy.
First let's define what I am NOT saying. (No apologies for the
capitals. Google doesn't allow italics or underlining)
I'm NOT saying that the local variant of DBTs known as ABX is the
wrong tool to use in research, with careful design,proper statistics,
selected research topics and last but not least SELECTED, TRAINED
SUBJECTS.

I have no knowledge, opinion, interest in the particulars of such
research because it does not research differences between real-life
audio components.
I'm NOT saying that those audiophiles who enjoy ABX and believe that
they get valid results should not use it. As long as they do not think
that their results are valid for anyone but themselves.
ALSO as long as they keep in mind that their negative, null
results are valid for them at this particular stage of their ABX
training and musical experience. As long as they remember that if they
do not revisit their negative results they may be shutting themselves
off FOREVER from enlarging and enriching their hi-fi scope.
I'm NOT , emphatically NOT saying that individuals shouldn't use
methods of their choice to disguise the brand of components that they
compare. I have one such method, myself which serves me well but may
not suit others..
What I do object to is the belief that to "prove" your opinions re
"difference" or "no difference"- a necessary preliminary to
preference- (more about difference/preference in my answer to
Audioguy.) one has to undergo a procedure known as ABX.
Please, don't one of you tell me that "nobody says that". Speak
for yourself. Every week somebody says just that in RAHE. Sometimes
with a pseudo-objective semantical word games.: "But you have not had
a "controlled test" (meaning ABX of course) so it is only your
impression..".- as though it could be anything else. Or "Reviewers
should undergo cotrolled test for credibility" as though it msde
stupid reviewers into clever ones. And of course you Mr. Nousaine said
it many times.

There are a few unspoken assumptions here
FIRST UNPROVEN ASSUMPTION: everyone performs just as well when ABXing
and when listening for pleasure blinded or not blinded.
Perhaps they do, perhaps they don't. In fact I presented evidence
suggesting that there is MARKED DIFFERENCE in people's performance
when listening to simple pink noise signal as opposed to listening to
a musical signal
I then asked Mr Miyaguchi a simple, straightforward question Is
there a difference? Instead of of a simple YES= there is a
difference (or NO- there isn't any- if anyone really wanted to play
the fool) I got convoluted explanations of WHY there is , further
beautified by you Mr. Nousaine. Incidentally I asked you the very same
question one month ago and never got an answer.
Why this dodging?. You can bet I'd get plain NO if there were NO
DIFFERENCE. and EVERYBODY who performed flawlessly listening to
pink noise would do just as well listening to music. But MOST
performed abominably, (consistent with random guessing) when listening
to music.. Explanation? Music is "more complex". Quite! And what else
is new?.Most of us use our components to listen to music, not pink
noise. If your test has problems with music is it the right one to
assess the differences in MUSICAL performance of components?
Where is the evidence ? Evidence where I come from ( see my answer to
Audioguy concerning that) is EXPERIMENTAL evidence not circular
arguments like : "Why shouldn't it be so? It is good enough for
codecs isn't it?" I listen to music not codecs. And I need convincing
that pink noise is the best way to test a component for its transient
response to a cymbal, or rendition of a violin or a cello. I'd suggest
to researchers:"Try again"
All you can name since 1990 Mr. Nousaine are your own cable tests from
1995. Where I come from (again-sorry1) one gives the mag's name, the
date, the page so that I can find out what was the design, who
proctored, how many subjects, how many tests etc. Why so shy with
details?
You say: "Likewise the body of controlled listening test results
can be very useful to any individual that wishes to make use of them to guide
decisions (re component choice)"

Where does one find that body? Buried in the pyramids or Alberta tar
sands?
Why not name a few ,recent representative offshoots?. Just to show
that Consumer ABXing is any use other than for discomfiting the naive.

Where are the current tests on current components?. You're not
serious saying that there's nothing new under the sun. Any difference
between the 24 bit and 16 bit cdplayers? Which dacs truly cope with
jitter?, Are the Meridian and Tact room equalising systems different
from any other equaliser? Any differences between the various digital
sound processing systems. Come on Mr. Nousaine. Winning verbal contest
against L. Mirabel is not everything. There is such a thing as putting
more information on the table.
Of course you are at least consistent, You truly believe that
there is no difference between any components at all: By your lights
such objectivist luminaries as Krueger and Pinkerton are pinkish
dissidents: " Actually if nominally competent components such as
wires, parts, bits and
amplifiers have never been shown to materially affect the sound of reproduced
music in normally reverberant conditions why would ANYONE need to conduct more
experimentation, or any listening test, to choose between components?"

And again. The profession of faith: " Examination of the extant body
of controlled listening tests available contain enough information to
aid any enthusiast in making good decisions."

And what information is it?:
" As I've said before; there are many proponents of high-end sound of
wires, amps and parts ... but, so far, no one (in over 30 years) has
ever produced a single repeatable bias controlled experiment that
shows that nominally competent
products in a normally reverberant environment (listening room) have any sonic
contribution of their own.
Nobody! Never! How about some evidence? I'll believe in BigFoot ....just show
me the body!


And I'll believe that there are no diferences between components
when you prove that your "bias =controlled test" does not have biases
of its own
My other unanswered question to you one month ago was:
Where is the evidence that untrained, unselected
individuals perform identically, when comparing complex musical
differences between components for a "test" as they do when they just
listen. Reasoning that they should is plausible but reasoning that at
least some of them don't is not irrational. Convincing, controlled
experiment with random control subjects etc. is missing.
Next consider the anti-common sense assumption that Tom and
Dick do their DBT assignement equally well and both are an identical
match for Harry. Should they? They are not identical in any other task
aptitude, in their fingerprints or their DNA.
If you agree that they would differ how do you justify YOUR
challenges to all and sundry to prove their perceptions by ABX.
Perhaps they are as hopeless as I'm at that task. Perhaps a violinist
will hear differences in the rendition of violin tone when not
bothered by a "test" but be a terrible subject for ABXing. Impossible?
Where is your experimental evidence that this does not happen?.

Where is the experimentation to show that the poor ABX test
subjects
would perform identically sitting and listening at home?
Finally your telling ME that " I think Ludovic is "untrainable"
because he will accept only answers he already believes are true"
really takes the cake. .I'm not propunding any "test". You are. I have
no faith to stick to. You BELIEVE in ABX. It is MY right to ask YOU
for evidence. And it is your job to give it.
You know it all perfectly well because you know what "research" and
"evidence" mean. Why copy the tactics of those who have only ignorant
bluster to offer?

Ludovic Mirabel

We're talking about Greenhill old test not because it is perfect but
because no better COMPONENT COMPARISON tests are available. In fact
none have been published according to MTry's and Ramplemann's
bibliographies since 1990.


This is simply not true. I have published 2 double blind tests personally, one
of which covered 3 different wires subsequent to 1990.


I frequently see the distinction being made between audio components
and other audio related things (such as codecs) when it comes to
talking about DBT's. What is the reason for this?

In my opinion, there are two topics which should not be mixed up:

1) The effectiveness of DBT's for determining whether an audible
difference exists
2) The practical usefulness of using DBT's for choosing one audio
producer (component or codec) over another.


Actually if nominally competent components such as wires, parts, bits and
amplifiers have never been shown to materially affect the sound of reproduced
music in normally reverberant conditions why would ANYONE need to conduct more
experimentation, or any listening test, to choose between components? Simply
choose the one with the other non-sonic characteristics (features, price,
terms, availability, cosmetics, style...) that suit your fancy.

Indeed 20 years ago, when I still had a day job, Radio Shack often had the
"perfect" characteristic to guide purchase, which was "open on Sunday."
I am not knowledgeable enough to decide on differences between
your and Greenhill's interpretation of the methods and results.
In my simplistic way I'd ask you to consider the following:
PINK NOISE signal: 10 out of 11 participants got the maximum possible
correct answers: 15 out of 15 ie. 100%. ONE was 1 guess short. He got
only 14 out of 15.
When MUSIC was used as a signal 1 (ONE) listener got 15 corrects,
1 got 14 and one 12. The others had results ranging from 7 and 8
through 10 to (1) 11.
My question is: was there are ANY significant difference between
those two sets of results? Is there a *possibility* that music
disagrees with ABX or ABX with music?


No: it just means with the right set of music 2 dB is at the threshold. Don't
forget that listening position affects this stuff too. Also Mr Atkinson would
say that perhaps the lower scoring subjects didn't have personal control of the
switching.

Even between two samples of music (no pink noise involved), I can
certainly believe that a listening panel might have more or less
difficulty in determining if they hear an audible difference. It
doesn't follow that music in general is interfering with the ability
to discriminate differences when using a DBT.


Actually it simp,y shows that pink noise and other test signals are the most
sensitive of programs. It may be possible to divulge a 'difference' with noise
that would never be encountered with any known program material.

It's also possible that certain programs, such as Arny Kreuger's special
signals, might disclose differences that may never be encountered with
commercially available music (or other) programs. So?

I would aoppreciate it if would try and make it simple leaving
"confidence levels" and such out of it. You're talking to ordinary
audiophiles wanting to hear if your test will help them decide what
COMPONENTS to buy.


As before; you haven't ever been precluded from making any purchase decisions
from scientific evidence before; why should any disclosure affect that now or
in the future.

Examination of the extant body of controlled listening tests available contain
enough information to aid any enthusiast in making good decisions. Even IF the
existing evidence shows that wire is wire (and it does) how does that preclude
any person from making any purchase decision? In my way of thinking it just
might be useful for a given individual to know what has gone before (and what
hasn't.)

I still don't know how this cannot do anything but IMPROVE decision making?

See my first comments. It's too easy to mix up the topic of the
sensitivity of DBT's as instruments for detecting audible differences
with the topic of the practicality of using DBT's to choose hifi
hardware. The latter is impractical for the average audiophile.


No it's not. Just like 0-60 times, skid-pad and EPA mileage tests simply cannot
be made by the typical individual that doesn't mean that they cannot be used to
improve decision-making. Likewise the body of controlled listening test results
can be very useful to any individual that wishes to make use of them to guide
decisions.

Otherwise the only information one has is "guidance" from sellers, anecdotal
reports and "open" listening tests. The latter , of course, is quite subject to
non-sonic influence.

So IMO, a person truly interested in maximizing the sonic-quality throughput of
his system simply MUST examine the results of bias controlled listening tests
OR fall prey to non-sonic biasing factors, even if they are inadvertent.


Who can argue with motherhood? The problem is that there are NO
ABX COMPONENT tests being published- neither better nor worse, NONE.
I heard of several audio societies considering them. No results.
Not from the objectivist citadels: Detroit and Boston. Why?. Did they
pan out?


Given the two dozen controlled listening tests of power amplifiers published
through 1991 doesn't it seem that no one needs to conduct more? Wires? The last
test I published was in 1995. Not late enough?

Why not? No manufacturer has EVER produced a single bias controlled experiment
that showed their wires had a sound of their own in over 30 years. Why should
one expect one now?

I certainly can't do it; although I've given it my level (no pun intended)
best. IOW, I can't produce an experiment that shows nominally competent wires
ain't wires .... 'cuz they ain't.

I can think of a couple of reasons:

1. It's expensive and time consuming to perfom this type of testing
2. The audible differences are, in actuality, too subtle to hear, ABX
or not. Why bother with such a test?


Why bother in performing a sound quality "test" that the manufacturers of the
equipment can't produce? IF amps ain't amps; wires ain't wires and parts ain't
parts then why haven't the makers and sellers of this stuff produced repeatable
bias controlled listening tests that show this to be untrue?

Then there is the possibility that you seem to be focussing on,
ignoring the above two:

3. DBT's in general may be decreasing the ability to hear subtle
differences.


Actually they preclude the ability to "hear" non-sonic differences.

Which of the the above reaons do you think are most likely?

Moving away from the question Greenhill was investigating
(audible
differences between cables) and focusing only on DBT testing and
volume differences: it is trivial to perform a test of volume
difference, if the contention is being made that a DBT hinders the
listener from detecting 1.75 dB of volume difference. Especially if
the listeners have been trained specifically for detecting volume
differences prior to the test.
However, such an experiment would be exceedingly uninteresting, and I
have doubts it would sway the opinion of anybody participating in this
debate.

The volume difference was just a by-effect of a comparison between
cables.
And yes, TRAINED people would do better than Greenhill's "Expert
audiophiles" ie rank amateurs just like us. Would some though do
better than the others and some remain untrainable? Just like us.


I think Ludovic is "untrainable" because he will accept only answers he already
believes are true.

I have no doubt that there are some people who are unreliable when it
comes to performing a DBT test. In a codec test using ABC/HR, if
somebody rates the hidden reference worse than the revealed reference
(both references are identical), his listening opinion is either
weighted less or thrown out altogether.


What you are describing is 'reverse significance' which is typically a
inadvertant form of internal bias.

For what it's worth, I have performed enough ABX testing to convince
myself that it's possible for me to detect volume differences 0.5 dB
using music, so I doubt very highly that a group test would fail to
show that 1.75 dB differences on a variety of different music are not
audible using a DBT.

I can easily hear 1db difference between channels, and a change
of 1 db.
What I can't do is to have 80 db changed to 81 db, then be asked if
the third unknown is 80 or 81 dbs. and be consistently correct.
Perhaps I could if I trained as much as you have done. Perhaps not
Some others could, some couldn't. We're all different. Produce a test
which will be valid for all ages, genders, extent of training, innate
musical and ABxing abilities, all kinds of musical experience and
preference. Then prove BY EXPERIMENT that it works for COMPARING
COMPONENTS.
So that anyone can do it and if he gets a null result BE CERTAIN that
with more training or different musical experience he would not hear
what he did not hear before. And perhaps just get on widening his
musical experience and then rcompare (with his eyes covered if he is
marketing susceptible)
Let's keep it simple. We're audiophiles here. We're talking about
MUSICAL REPRODUCTION DIFFERENCES between AUDIO COMPONENTS. I looked
at your internet graphs. They mean zero to me. I know M. Levinsohn,
Quad, Apogee, Acoustat not the names of your codecs. You assure me
that they are relevant. Perhaps. Let's see BY EXPERIMENT if they do.
In the meantime enjoy your lab work.
Ludovic Mirabel


Are you really telling me that you didn't understand the gist of the
group listening test I pointed you to?

For one thing, it says that although people have different individual
preferences about how they evaluate codec quality, as a group, they
can identify trends. This, despite the variety of training, hearing
acuity, audio equipment, and listening environment.

Another point is that it would be more difficult to identify trends if
such a study included the opinions of people who judge the hidden
reference to be worse than the revealed reference (simultaneously
judging the encoded signal to be the same as the revealed reference).
In other words, there are people whose listening opinions can't be
trusted, and the DBT is designed to identify them.


That result identifies a form of experimental bias, does it not?

The last point is that I can see no reason why such procedures could
not (in theory, if perhaps not in practical terms) be applied to audio
components. Why don't you explain to me what the difference is (in
terms of sensitivity) between using DBT's for audio codecs and using
DBT's for audio components?

Darryl Miyaguchi


There is no difference. It seems to me that this poster may have never taken a
bias controlled listening test or, if he has, the results didn't fit with prior
held expectations. It's much easier to argue with the existing evidence than
prove that you can hear things that no human has been able to demonstrate, when
not peeking.

As I've said before; there are many proponents of high-end sound of wires, amps
and parts ... but, so far, no one (in over 30 years) has ever produced a single
repeatable bias controlled experiment that shows that nominally competent
products in a normally reverberant environment (listening room) have any sonic
contribution of their own.

Nobody! Never! How about some evidence? I'll believe in BigFoot ....just show
me the body!


  #12   Report Post  
ludovic mirabel
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

(Bob Marcus) wrote in message ...
(ludovic mirabel) wrote in message ...

Snip. I said:
I can easily hear 1db difference between channels, and a change
of 1 db.
What I can't do is to have 80 db changed to 81 db, then be asked if
the third unknown is 80 or 81 dbs. and be consistently correct.


Two questions:

1) What do you mean by "consistent"? 100% of the time, or just with
statistical reliability?

2) Were you able to switch instantaneously between them? Audiophiles
pooh-pooh this, but it's certainly easier to hear level differences
when you can switch instantaneously.


I'm not aware of any evidence that musical experience is particularly
helpful in these kinds of tests. That's not what "training" is about
in this context.

Interesting. "We" don't "believe" that musical experience has anything
to do with music reproducing components.

Snip
So far as I can tell, the only experiment that would satisfy you would
be one that confirmed your own beliefs about what is and is not
audible. I'm afraid we can't do that.

bob


The "instantaneous switch" is my stepped volume control. It is in
working order.
As for "statistical reliability"- how consistently do I hear the 1db.
volume difference when I switch?
100% of the time when full range music or voice are playing. . Like
everyone else not totally deaf would- Mr Myaguchi for one hears 0.5 db
volume change
I'm not reporting the results of a controlled lab test but my
experiences.
Anyone disbelieving me is free to do so.
I also am not on a witness stand in court. Should I be foolish
enough to engage in this exchange your next question might be: " Have
you any witnesses?"
"Did you say your wife? When did you stop beating your wife to get
her to witness for you?"
We're in an audiophile forum not in court Mr. Marcus.
You will not spell your qualifications for instructing others to
learn those subjects together and separately : statistics,
electronics, psychoacoustics, details of medical drug research, but
you're again telling me what "we' can or cannot do in those areas..
Who are those "we"? Lawyers? You're a lawyer aren't you?. Unless like
in all those other areas you took one course or read one law book.
As for the rest of your message; it is just a rehash of what 4 other
participants said more ably and with more inside knowledge. . Read my
answers to them.
Ludovic Mirabel

  #13   Report Post  
S888Wheel
 
Posts: n/a
Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

I said


I examined the results of contained in the articles you sent me and
do not find them conclusive.


Arny said



This begs the question as to whether there exists any evidence that would be
found to be conclusive by certain persons.


By certain persons I suspect you are including me. That is an interesting
question. Does such a body of evidence even exist? When Tom Nousiane made his
offer of such evidence the body of evidence he offered was hardly conclusive
about the audibility of amplifiers. This begs the question are some people
drawing definitive conclusions with less than adequate evidence to draw such
conclusions? Do you think the two cited articles supply sufficient evience to
draw any definitive conclusions about the audibility of amplifiers? Do you
think the evidence in those articles qualify as scientifically valid bodies of
empirical evidence? Do you think the issue of test sensitivity was sufficiently
addressed in those tests based on the content of those articles?

I said


Unfortunately four of the six articles
you sent me had no raw data to examine and only offered conclusions.


Arny said


Would this have made a difference?


It does to me when I am asking for empirical evidence. conclusions and analysis
is not data. analysis and conclusions without the raw data is just opinions
IMO.

I said



Given the fact that the two articles that did offer raw data drew
conclusions that I find questionable i have trouble feeling confident
about the conclusions drawn in the other articles missing the raw
data.


Arny said



Bottom line, there are plenty of opportunities now to do your own
experiments, gather and analyze your own data, etc.


1. That is irrelevant. Tom was claiming one could use the extant body of
evidence to make purchasing decisions. I was addressing that claim. 2. That is
not neccessarily true. Unless if we are trying to limmit this to scientifically
valid tests.

I said


So I find the evidence to date that I have seen less than
helpful in purchase decisions.


Arny said


The problem here relates to being able to obtain abstract knowledge and
apply it.

Nonsense. this is just a personal attack. Please show how I have failed to
either obtain or apply absrtact knowledge in this case. Do you think Tom
Nousiane has failed in his attempt to supply me with the best empirical
evidence on the subject? do you think the cited tests offer evidence upon which
one can draw definitive conclusions about the sound of amplifiers? Please
specifically support your inference that I have failed intelectually in my
edeavour to "obtain abstract knowledge and apply it" on this subject. If you
can't then please retract your claims on this matter. They are offensive.

Arny said

Once I found that dramatic audible differences between good
cables,SS amplifiers and/or CD players just don't exist; I started basing my
purchase decisions on differences that do exist.



Dramatic is a subjective adjective. What is dramatic to one person is
insignificant to another. Maybe we should stick to the subject of audible
differences.
  #14   Report Post  
ludovic mirabel
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

Darryl Miyaguchi wrote in message ...
On 1 Jul 2003 15:10:59 GMT, (ludovic mirabel)
wrote:

Apologies for rearranging your text for my convenience.
You say:
In my opinion, there are two topics which should not be mixed up:

1) The effectiveness of DBT's for determining whether an audible
difference exists
2) The practical usefulness of using DBT's for choosing one audio
producer (component or codec) over another.

Let me be quite brutal about this.
My ONLY concern and interest is in part 2. I'm reading and
participating in RAHE not because I'm interested in psychometric
research but exactly for help to "choose one audio producer over
another". And the "producer" that I'll use in my listening room is
not codec but a musical reproducing device.
I may just as well tackle the question of codec or any other artefact/
vs. a musical audio device.
Are they different? I don't know. You challenge me below to
demonstrate why they shouldn't behave identically. The shoe is on the
other foot- you have first to show that they would.
I'll have to explain something he Basically I come from a different
corner of science from yours. Mine is applied science not basic
research. You ask me why codex shouldn't act like amplifiers. Maybe
they do.

But till there is a convincing experiment to show that it is so, to me
it is just more inference, reasoning by analogy.
For millenia physicians reasoned, speculated and looked at analogies.
The diseased blood is full of noxious miasmas so let's bleed poor Lord
Byron to death.
Sometime in the XXth century things changed. The question to ask
became not: "Is it likely to work because Herr Professor thinks it
should or because there are "good reasons" why it should? or what not.
It became: "Can I design an experiment to show if it will or will not
WORK ?" Reasoning and speculation be damned in medical research-
coarse practicality culminating in Random controlled Double Blind
testing rules. Patient's answers, doctor's impressions are collected
for documentation- the outcome is decided by demonstrable physical
changes.
All that I said before, But now I come to Codex vs Amplifier. No
matter how close the analogy you make it means nothing in the applied
medical research. Add one hydrogen binding to a life saving drug and
it becomes a killer. Of course the Rhinoceros are being exterminated
because the upright horn is a cure for impotence in China. An unfair
(I confess) reductio ad absurdum of reasoning by analogy: " Why
shouldn't the horn work? It looks like IT doesn't it?"

I said:
I am not knowledgeable enough to decide on differences between
your and Greenhill's interpretation of the methods and results.
In my simplistic way I'd ask you to consider the following:
PINK NOISE signal: 10 out of 11 participants got the maximum possible
correct answers: 15 out of 15 ie. 100%. ONE was short of 100%t. He got
only 14 out of 15


But when MUSIC was used as a signal 1 (ONE) listener got 15 corrects, one got 14 and one 12. The others had results ranging from 7 and 8 through 10
to 11.(one)
My question is: was there are ANY significant difference between
those two sets of results? Is there a *possibility* that music
disagrees with ABX or ABX with music?


You answered:
Even between two samples of music (no pink noise involved), I can
certainly believe that a listening panel might have more or less
difficulty in determining if they hear an audible difference. It
doesn't follow that music in general is interfering with the ability
to discriminate differences when using a DBT.

Sorry, but the questiion is a simple one :"Did THIS panel perform
differently on pink noise and music or not?"
And the answer should be simple: Yes or No. Once you answer that you
can give your qualifiers, explanations and so on..

You said:
It's too easy to mix up the topic of the
sensitivity of DBT's as instruments for detecting audible differences
with the topic of the practicality of using DBT's to choose hifi
hardware. The latter is impractical for the average audiophile.

As I said before the only topic I'm interested in is exactly the
"practicality" of its use for comparing components. Were I interested
in DBT sensitivity for other *audible differences* I'd be reading JAES
or a "Journal of Psychometrics" (if there is such a thing) -not RAHE.
But your last sentence certainly rings true- that's why your getting
in hot water with the Old Believers is to be expected.

You said that good ABX component tests are possible (paraphrase). I
answered:
Who can argue with motherhood? The problem is that there are
NO ABX COMPONENT tests being published- neither good nor bad, NONE.
I heard of several audio societies considering them. No results.
Not from the objectivist citadels: Detroit and Boston. Why?. Did
they not pan out?


Your answer:

I can think of a couple of reasons:

1. It's expensive and time consuming to perfom this type of testing
2. The audible differences are, in actuality, too subtle to hear, ABX
or not. Why bother with such a test?

Then there is the possibility that you seem to be focussing on,
ignoring the above two:

3. DBT's in general may be decreasing the ability to hear subtle
differences.

Which of the the above reaons do you think are most likely?


If you ask me : the last one. Enough changed in audio since 1990 to
spur newer comparisons. (See my posting to Mr. Audio Guy). It is
expensive but not beyond the possibilities of such as Boston Audio
Socy. I saw the design of a Seattlee AUDIO Socy AbX test. Then
silence. No results. Was it your reason 3.? I don't know and I never ,
never speculate. Especially since the stock market expired. If it
works why don't people do it?

You asked:
Are you really telling me that you didn't understand the gist of the
group listening test I pointed you to?

For one thing, it says that although people have different individual
preferences about how they evaluate codec quality, as a group, they
can identify trends. This, despite the variety of training, hearing
acuity, audio equipment, and listening environment.

Another point is that it would be more difficult to identify trends if
such a study included the opinions of people who judge the hidden
reference to be worse than the revealed reference (simultaneously
judging the encoded signal to be the same as the revealed reference).
In other words, there are people whose listening opinions can't be
trusted, and the DBT is designed to identify them.

Re "trends and statistical averages:" How "likely" am I to hear those
musical differences under ABX that I heard without it? As likely as
the 72% of Greenhill's subjects who failed at a much simpler task when
being ABXed?.
Or do you have any other experimentally proven statistics?
Let me say something about statistics as applied to prognosis (
outcome forecasting) in medicine.
A patient has inoperable lung cancer. His family want to know how long
he'll live. If you're a heartless fool you say: "average survival with
this is 6 months."
If you're a clever and humane physician you say:" Whatever I'll say
you'll probably want to check in the Public Library anyway- you'll
find a 6 months AVERAGE survival rate . But you husband's name is Joe
Smith not Joe Average. Some die in a few weeks, some in a couple of
years and some-very, very few have an unexplainable, complete
disappearance of the growth. I can not tell exactly how long your
husband will live, but more likely months than years."
A "test" which depends on statistics can not be used as a universally
recommended method of differentiation. It may be O.K. for some and
worse than useless for the others. And the devil is that no one can
tell if he is being deceived by it when he gets a null result because
he may perform differently in 6 months time or when not bothered by
ABX. Or not. Do it at your own risk. Like choosing a book to read, a
movie to attend or wine to drink. Nobody pesters you with a" test"
there. Sorry, "trends" are good for public opinion polls, not as
guidance for inndividuals.

The last point is that I can see no reason why such procedures could
not (in theory, if perhaps not in practical terms) be applied to audio
components. Why don't you explain to me what the difference is (in
terms of sensitivity) between using DBT's for audio codecs and using
DBT's for audio components?


I will not repeat why I consider the above an example of reasoning by
similarity and analogy without experimental evidence. And THAT YOU
fail to supply. Once you do that I'll see if the experiments were well
designed, properly carried out, had good controls and so on.
Ludovic Mirabel

  #15   Report Post  
Darryl Miyaguchi
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

On Fri, 04 Jul 2003 17:40:00 GMT, (ludovic
mirabel) wrote:

Darryl Miyaguchi wrote in message ...
On 1 Jul 2003 15:10:59 GMT,
(ludovic mirabel)
wrote:

Apologies for rearranging your text for my convenience.
You say:
In my opinion, there are two topics which should not be mixed up:

1) The effectiveness of DBT's for determining whether an audible
difference exists
2) The practical usefulness of using DBT's for choosing one audio
producer (component or codec) over another.

Let me be quite brutal about this.
My ONLY concern and interest is in part 2. I'm reading and
participating in RAHE not because I'm interested in psychometric
research but exactly for help to "choose one audio producer over
another". And the "producer" that I'll use in my listening room is
not codec but a musical reproducing device.


Your claim is that DBT's reduce the ability to discriminate
differences in music using audio components. This is a very specific
claim which relies upon several assumptions:

1. DBT's reduce, in general, the ability to discriminate differences.

Some evidence to the contrary:

ABX has been successfully used to differentiate truncation vs.
dithering at 16 bits:

http://ff123.net/24bit/24bitanalysis.html

ABX has been successfully used to discriminate volume differences in
music of less than 0.5 dB (personal tests).

2. ABX may be ok for pink noise, but not for music.

A controlled test (Greenhill's) showed decreased listener sensitivity
when choral music was presented instead of pink noise. From this you
infer that ABX is not suited for music. Again, I must point out that
this inference is flawed. The simpler and more likely explanation is
that all types of listening methods (included sighted listening) are
affected by musical selection.

3. DBT's may be ok for audio codecs, but not for comparing audio
components.

We seem to disagree on this basic point, although I will point out
that you can hardly claim that the onus is on me to provide evidence
that the two situations are similar. If I assume a certain position
(that the human ear/brain behaves similarly, according to the same
psychoacoustic descriptions, regardless of the audio source), then
your position is surely an assumption as well, and IMO more
speculative. I choose the null hypothesis (there is no difference)
until I see evidence to the contrary.

Sorry, but the questiion is a simple one :"Did THIS panel perform
differently on pink noise and music or not?"
And the answer should be simple: Yes or No. Once you answer that you
can give your qualifiers, explanations and so on..


See my separate post to this.

cut

3. DBT's in general may be decreasing the ability to hear subtle
differences.

Which of the the above reaons do you think are most likely?


If you ask me : the last one. Enough changed in audio since 1990 to
spur newer comparisons. (See my posting to Mr. Audio Guy). It is
expensive but not beyond the possibilities of such as Boston Audio
Socy. I saw the design of a Seattlee AUDIO Socy AbX test. Then
silence. No results. Was it your reason 3.? I don't know and I never ,
never speculate.


The irony of this statement must have escaped you. As far as I can
tell, your position *is* speculative, given that it is based on very
specific assumptions (see above).

Especially since the stock market expired. If it
works why don't people do it?


cut

A "test" which depends on statistics can not be used as a universally
recommended method of differentiation. It may be O.K. for some and
worse than useless for the others. And the devil is that no one can
tell if he is being deceived by it when he gets a null result because
he may perform differently in 6 months time or when not bothered by
ABX. Or not. Do it at your own risk. Like choosing a book to read, a
movie to attend or wine to drink. Nobody pesters you with a" test"
there. Sorry, "trends" are good for public opinion polls, not as
guidance for inndividuals.


Hearing perceptions are more similar from person to person than their
preferences in books or movies or taste in wine. If they weren't,
people wouldn't have been able to design audio codecs, which rely upon
universal characteristics of human hearing.

However, it is true that people have varying ability to hear certain
things, and that this variation affects their preferences.

There are two answers to the question "Which sounds best?" One answer
is the one each individual gives after personal audition. The other
answer is based on group results. Which answer one should choose is
based on the particular circumstance.

Darryl Miyaguchi



  #16   Report Post  
S888Wheel
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

I have no "evidence" for my perception that silver wires a la Kimber
sound better- TO ME- than copper (even when I'm blinded). None that
would satisfy you and none, in truth- that would satisfy a critical
peer-review.
MORE- I don't believe that such "evidence" is possible outside of RAHE
wishful fantasies. I don't believe that there is experimental
evidence (see my answer to Nousaine) that a technique, such as the
audio version of DBT has been shown to be capable of invalidating
mine or anyone else's perceptions.


I have to take issue with this claim. Any claims that suggest a physical
manifestation of any phenomenon is a testable claim. If you claim to hear
differences it is a testable claim.
  #17   Report Post  
Mkuller
 
Posts: n/a
Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

(Stewart Pinkerton) wrote:
Ludovic Mirabel, for instance, has posted thousands of lines of text
in various attempts to discredit what evidence exists to support the
notion that 'wire is wire', and that, by and large, 'amps is amps',
yet he has offered absolutely *zero* evidence to support his own
beliefs.


Obviously, your "evidence" is NOT sufficient to convince anyone (who does not
already believe) that "amps is amps" and "wire is wire". I would suggest that
any "evidence" LM and those on the other side of this debate would show YOU (or
have shown you) would be insufficient to convince you, since you have long ago
made up your mind.

So what exactly do you hope to accomplish by continuing this endless "debate"?
Isn't one definition of "insanity", 'continuing to repeat the same behavior,
but expecting a different result'?
Regards,
Mike

  #18   Report Post  
Nousaine
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

(S888Wheel) wrote:

Tom said


Actually if nominally competent components such as wires, parts, bits and
amplifiers have never been shown to materially affect the sound of

reproduced
music in normally reverberant conditions why would ANYONE need to conduct
more
experimentation, or any listening test, to choose between components? Simply
choose the one with the other non-sonic characteristics (features, price,
terms, availability, cosmetics, style...) that suit your fancy.


That is the 64,000 dollar if.

Tom said


Examination of the extant body of controlled listening tests available
contain
enough information to aid any enthusiast in making good decisions. Even IF
the
existing evidence shows that wire is wire (and it does) how does that
preclude
any person from making any purchase decision? In my way of thinking it just
might be useful for a given individual to know what has gone before (and

what
hasn't.)


Well, so far I don't see it the way you do. I must at this point thanl you
for
the articles on this subject you sent me when I asked for the alleged body of
empirical evidence that prooved your position on the audible differences of
amplifiers.


I said that a body existed. I offered to send you Some of the existing evidence
because you said that you hadn't seen "any."

The "body of evidence" you sent me that constituted actual
evidence, raw data, was not much of a body. Only two articles out of the six
you sent had raw data ( "Can you trust your ears" by Tom Nousiane and "Do all
amplifiers sound the same" by David Clark) and only the test you conducted
had
it in a usful table which could allow for the examination of trends such as
learning curves or fatigue curves.


Let's be clear here. I did not offer to send you "the" body of evidence. You'll
see "The Great Debate; Is Anybody Winning" a list of over twenty controlled
listening tests on amplifiers conducted prior to 1990.

As to raw data "The Great Chicago Cable Caper" and "To Tweak or Not To Tweak"
both contained raw data.

First, this is not much of a body of
evidence. Second, if we are to draw conclusions from the results we would
have
to conclude that some people can hear differences between amps and some amps
sound idfferent than some other amps.


None of the raw data suggests that.

Of course it would be a mistake to draw
conclusions from those tests by themselves because they simply are not that
conclusive. If what you sent me is the best evidence out there and if what
you
sent me is any significant portion of the much talked about "extant body of
controled listening tests available" then I don't see how anyone can draw any
strong conclusions one way or another.


What is so funny is that I offered to send you copies of some data because you
claimed to have not seen ANY of the approximately 3 dozen controlled listening
tests that had been published in popular journals over the years. I didn't
offer to send you all data that exists.

If you were truly interested you should do some of your own homework. But it
certainly doesn't seem that you do have a true interest.

And you're missing an important point; no one has produced a single repeatable
experiment in normal listening conditions where nominally amps, wires or parts
have been shown to have an audible effect.

The ONLY existing evidence on your side for amplifiers is pcabx which uses a
overly sensitive microscope-like technique that doesn't represent the typical
sighted conditions where 'amp differences' are often made.

Tom said


So IMO, a person truly interested in maximizing the sonic-quality throughput
of
his system simply MUST examine the results of bias controlled listening

tests
OR fall prey to non-sonic biasing factors, even if they are inadvertent.


I examined the results of contained in the articles you sent me and do not
find them conclusive. Unfortunately four of the six articles you sent me had
no
raw data to examine and only offered conclusions.


Again, all of them contained raw data except for the summary piece which listed
over twenty reports that you can track down if you have interest.

Given the fact that the two
articles that did offer raw data drew conclusions that I find questionable i
have trouble feeling condifent about the conclusions drawn in the other
articles missing the raw data. So I find the evidence to date that I have
seen
less than helpful in purchase decisions.


So you will reject any data that doesn't support your prior held conclusions. I
figured that would be your position. Why not try to find ANY credible data that
does? Happy hunting.

  #19   Report Post  
Nousaine
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

(S888Wheel) wrote:

....many snips....

By certain persons I suspect you are including me. That is an interesting
question. Does such a body of evidence even exist? When Tom Nousiane made his
offer of such evidence the body of evidence he offered was hardly conclusive
about the audibility of amplifiers.


Please don't make up things that I didn't offer. You said you had never seen
ANY evidence about the audibility of amps, wires and parts. I offered to send
you one such report. Indeed one of the ones I did send you lists a couple dozen
amp experiments.

What I find interesting is that not ONE credible, replicable bias controlled
report verifying the audibility of nominally competent amps, wires or
capacitors in normally reverberant conditions exists. Not one.

This begs the question are some people
drawing definitive conclusions with less than adequate evidence to draw such
conclusions? Do you think the two cited articles supply sufficient evience to
draw any definitive conclusions about the audibility of amplifiers?


Find a credible one that suggests otherwise, why don't you?

Do you
think the evidence in those articles qualify as scientifically valid bodies
of
empirical evidence? Do you think the issue of test sensitivity was
sufficiently
addressed in those tests based on the content of those articles?


Yes. Definitely.


I said


Unfortunately four of the six articles
you sent me had no raw data to examine and only offered conclusions.


Arny said


Would this have made a difference?


It does to me when I am asking for empirical evidence. conclusions and
analysis
is not data. analysis and conclusions without the raw data is just opinions
IMO.


The statemrnt about lack of data is simply not true. All the reports sent to
him contained raw data. The other was a compilation of results from a couple
dozen previously conducted amplifier tests. All Mr Wheel has to do is look them
up.

But again he originally suggested that no evidence on the matter, one way or
another, actually existed.

At the very least one should recognize that plenty of it exists, that
interested parties have had public access to same over the past 30 years and
that you can't find a single experiment that supports the claimed audibility of
amps and wires.


I said



Given the fact that the two articles that did offer raw data drew
conclusions that I find questionable i have trouble feeling confident
about the conclusions drawn in the other articles missing the raw
data.


What's funny is that Mr Wheel examines the raw data and rejects the conclusion
"no single listener was able to reliably identify amps under blind consitions"
that the data clearly depicted.


Arny said



Bottom line, there are plenty of opportunities now to do your own
experiments, gather and analyze your own data, etc.


1. That is irrelevant. Tom was claiming one could use the extant body of
evidence to make purchasing decisions. I was addressing that claim. 2. That
is
not neccessarily true. Unless if we are trying to limmit this to
scientifically
valid tests.


I've been making high quality decisions based on this evidence for a quarter
century.

I said


So I find the evidence to date that I have seen less than
helpful in purchase decisions.


Those who will not see and won'y examine historyt are doomed to repeat
historical mistakes and apply resources intended to improve sound quality that
have no sound quality aspect.

  #20   Report Post  
Nousaine
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

Darryl Miyaguchi wrote:

On 3 Jul 2003 02:52:02 GMT,
(Nousaine) wrote:

Perhaps we're missing each others points here. With the common ABC/Hr

protocol
the listener is asked to identify one alternative as being the same as the
reference and to grade the alternative on a downward rating scale.

If I'm taking your point correctly those listeners that reliably rate an
alternative as being worse than itself have responses thrown out. If so,

this
could be a conscious form of subject bias.

But it could also be a form of experimental bias where some form of other
identification cue is involved. In either case SOME form of bias is present;
just as 'reverse' significant results in common A/B Same/Different or even

ABX
tests would indicate.

Backward significance is always an indictator that some form of bias is
present.


Just so that we don't misunderstand exactly what is happening during
one of these comparative tests:

Note the implementation of ABC/Hr being used:

http://ff123.net/abchr/abchr.html

The reference is not being presented as another codec. In the process
of rating each codec, the listener must choose from the hidden
reference.


Yes, the hidden reference is the original unprocessed source.

This is different from MUSHRA, where there is a hidden
reference, but which is typically presented as another codec. I think
we're both on the same page when talking about ABC/Hr, but I just want
to make sure.

When I speak of a bias, I am mostly concerned that one codec is not
falsely preferred over another.

In the ABC/Hr implementation we're discussing, suppose a listener
downrates the hidden reference for one or more codecs. Such a
listener is not an *outlier* -- he is clearly *incorrect*. Then, the
procedure used would be to discard that particular listener's entire
set of results for all codecs.

I don't believe there is a preferential bias of the type I am
concerned about. Instead, I believe that what is happening is that
statistical noise is being reduced when unreliable listeners are
removed, but possibly sensitivity is being reduced as well for the
reasons I outlined in my previous post. Reduced sensitivity is ok for
the purposes of this experiment; preferential bias is not.


Actually in the ABC/Hr protocol any listener reliably rating the hidden
reference worse than itself has demonstrated SOME form of test or subject bias.
Ther eis no other explanation; either the protocol has some form of non-sonic
confounding identifier OR the subject can truly hear the difference and is
purposefully responding in a backward manner.

I'm all for rejecting biased data but any kind of significant "reverse" results
shoyld be followed by an examination of the experiment to find whether it's
specific to a given subject(s). If the latter cannot be shown then the entire
experiment can be ruled invalid.


Now, one could argue that this procedure is selecting a special group
out of the test population. If one of the purposes of the experiment
is to represent a certain listening population, then throwing out
unreliable listeners is changing things. However, this particular
test makes no pretensions of representing the average listener. The
people who participate in this type of experiment are already
self-selected, and likely to be more sensitive than the average Joe.


Most likely true.


Is there some mechanism whereby you think that some sort of bias
(falsely preferring one or more codecs over others) may be operating
if unreliable results of the type described are thrown out? I can't
think of any.

Darryl Miyaguchi


As I said earlier if you cannot determine that results were limited to a given
subject(s) then the whole experiment must be considered suspect. At the very
least it should be repeated.


  #21   Report Post  
S888Wheel
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

I said

By certain persons I suspect you are including me. That is an interesting
question. Does such a body of evidence even exist? When Tom Nousiane made

his
offer of such evidence the body of evidence he offered was hardly conclusive
about the audibility of amplifiers.


Tom said


Please don't make up things that I didn't offer.


Well here is what the record shows

"Tom said

Yes, of course. I have spent the time and money to acquire all I can about
listening tests and what they show. My copy of the Proceedings wasn't free; so
are you expecting me to send you or Scott a free copy? I've done the same
formany. Just ask.

I said

Consider it asked.

Tom said

snail mail address please."

Maybe I am missing something but that looks like such an offer to me.

Tom said

You said you had never seen
ANY evidence about the audibility of amps, wires and parts. I offered to send
you one such report. Indeed one of the ones I did send you lists a couple
dozen
amp experiments.


I said I have never seen any scientifically valid empirical evidence on the
matter.You sent six articles only two of which had the raw data I was asking
about.The two that had raw data had not been published in a peer reviewed
scientific journal so they do not qualify as scientifically valid. It was nice
of you to send the six articles. Thank you. In light of the fact that I was
asking about *any scientifically valid empirical evidence that supported your
position on the audibility of amps*. My comments on the two articles that
actually had raw data stands. I don't recall any limmits of only one report.

Tom said


What I find interesting is that not ONE credible, replicable bias controlled
report verifying the audibility of nominally competent amps, wires or
capacitors in normally reverberant conditions exists. Not one.


What I find interesting is the best *evidence* you sent me on the matter was
IMO inconclusive. Some of the evidence in the Clark article suggested that
perhaps some people can hear differences and that some amps tested sounded
different to other amps tested. So how do you deal with that? Do you
acknowledge the test was inconclusive which is what I see or do you claim the
test gives us scientifically valid empirical evidence upon which we can draw
definitive conclusions?

I said

This begs the question are some people
drawing definitive conclusions with less than adequate evidence to draw such
conclusions? Do you think the two cited articles supply sufficient evience

to
draw any definitive conclusions about the audibility of amplifiers?


Tom said


Find a credible one that suggests otherwise, why don't you?


The article on the Clark tests certainly did suggest that some people can hear
differences and that some amps sound different than others.

I said

Do you
think the evidence in those articles qualify as scientifically valid bodies
of
empirical evidence? Do you think the issue of test sensitivity was
sufficiently
addressed in those tests based on the content of those articles?


Tom said


Yes. Definitely.


How? There was no scientific peer review. Are you going to ignore the protocols
of the scientific world? I think issue of test sensitivity in both cited
articles were quite poorly addressed. So much so that one can draw multiple
conclusions from the results such as the listeners may have not been sensitive
enough. The setup may not have been releavling enough etc. A bad mistake IMO.


I said


Unfortunately four of the six articles
you sent me had no raw data to examine and only offered conclusions.



Arny said


Would this have made a difference?


I said


It does to me when I am asking for empirical evidence. conclusions and
analysis
is not data. analysis and conclusions without the raw data is just opinions
IMO.


Tom said


The statemrnt about lack of data is simply not true.


Yes it is. Only two of the articles had the raw data.

Tom said

All the reports sent to
him contained raw data.


Straw man. I said "the raw data" which implies all of it. Only two of the six
did this. Heck some of the articles had no raw data.

Tom said

The other was a compilation of results from a couple
dozen previously conducted amplifier tests.


Right. They were an analyisis of data that was not presented in the raw. That
was exactly what I did not want as I already explained.

Tom said

All Mr Wheel has to do is look them
up.


As if this is an easy and cost free task. We've been down this road before. I
have been on too many fruitless Easter egg hunts on this subject. If those
claiming the existance of evidence cannot provide it than it is unreasonable
for them to expect me to go find it IMO.

Tom said


But again he originally suggested that no evidence on the matter, one way or
another, actually existed.


Baloney! Never suggested it. Cite your proof or withdraw the claim please. It
is a misrepresentation of anything I said or believe.

Tom said

At the very least one should recognize that plenty of it exists, that
interested parties have had public access to same over the past 30 years and
that you can't find a single experiment that supports the claimed audibility
of
amps and wires.


All I have done is ask to see it. To date not much has been shown to me and
what has been shown is hardly something one could base any definitive
conclusions upon. What you sent me did not prove your position at all.

Tom said



What's funny is that Mr Wheel examines the raw data and rejects the
conclusion
"no single listener was able to reliably identify amps under blind
consitions"
that the data clearly depicted.


Wrong.In the Dave Clark test listener #2 got 30/48 correct with a statistical
relaibility of hearing a difference of 94% Listener #6 got 26/48 with a
statistical probablity of 84% chance of hearing differences. Listener #15 got
15/21 correct with an 81% chance of hearing a difference. Given the fact that
no tests were done to measure listener's hearing acuity and no tests were done
to varify test sensitivty to known barely aduible differences one cannot
conclude anything other than those listeners may have heard differences. Bell
curves have no meaning without data on the listener's hearing acuity. The
logicqal thing would have ben to do follow up tests on those listeners to see
if it was just a fluctuation that fits within the predicted bell curve or if
they really could hear differences as the results suggest. Hence there is no
conclusive evidence from this test that as you say"no single listener was able
to reliably identify amps under blind conditions. Further more many different
amps were used in this test. If some do sound the same and some do sound
different this will have an affect on everyone's score and the bell curve.For
example a Counterpoint amp was compared to an NAD amp and the results of 30/48
correct answers with a probablity of 94% that a difference was heard. Yet no
follow up was done on this comparison.


Arny said



Bottom line, there are plenty of opportunities now to do your own
experiments, gather and analyze your own data, etc.


I said


1. That is irrelevant. Tom was claiming one could use the extant body of
evidence to make purchasing decisions. I was addressing that claim. 2. That
is
not neccessarily true. Unless if we are trying to limmit this to
scientifically
valid tests.


Tom said


I've been making high quality decisions based on this evidence for a quarter
century.


I believe you believe that.


I said


So I find the evidence to date that I have seen less than
helpful in purchase decisions.



Tom said


Those who will not see and won'y examine historyt are doomed to repeat
historical mistakes


Something politicians should pay attention to. We are not talking history here
we are talking evidence. If you can find fault with my analysis of the evidence
that we have discussed please cite it and prove it.

  #22   Report Post  
Steven Sullivan
 
Posts: n/a
Default Why DBTs in audio do not deliver

Mkuller wrote:
(Stewart Pinkerton) wrote:
Ludovic Mirabel, for instance, has posted thousands of lines of text
in various attempts to discredit what evidence exists to support the
notion that 'wire is wire', and that, by and large, 'amps is amps',
yet he has offered absolutely *zero* evidence to support his own
beliefs.


Obviously, your "evidence" is NOT sufficient to convince anyone (who does not
already believe) that "amps is amps" and "wire is wire". I would suggest that
any "evidence" LM and those on the other side of this debate would show YOU (or
have shown you) would be insufficient to convince you, since you have long ago
made up your mind.


So what exactly do you hope to accomplish by continuing this endless "debate"?


You might want to ask the person who *STARTED THE THREAD*.

hint: he's on *your* 'side'

--
-S.

  #24   Report Post  
S888Wheel
 
Posts: n/a
Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

Ludonvic said

I have no "evidence" for my perception that silver wires a la Kimber


sound better- TO ME- than copper (even when I'm blinded). None that
would satisfy you and none, in truth- that would satisfy a critical
peer-review.
MORE- I don't believe that such "evidence" is possible outside of RAHE
wishful fantasies. I don't believe that there is experimental
evidence (see my answer to Nousaine) that a technique, such as the
audio version of DBT has been shown to be capable of invalidating
mine or anyone else's perceptions.


I said


I have to take issue with this claim. Any claims that suggest a physical
manifestation of any phenomenon is a testable claim. If you claim to hear
differences it is a testable claim.



Ludvic said


Mr.S888wheel. Did you just wake up?


No.

Ludvic said

Everything is testable - IF you
have a way, a test, a method of doing it. Just that tiny, unimportant
point.


There are available methods to test your claim.

Ludvic said


If I say that there must be life somewhere in the universe outside of
Earth it is testable claim if you have a test.


Bad analogy. That claim is not testable do to the lack of resources. your claim
of audibility is a specific claim that does not require an investigation beyond
human resources.

Ludvic said

And it is the existence
of such a
test for audio components that we've been debating here for the last
two years.


I believe you have been debating the merits of ABX testing. One could test your
claims scientifically without using ABX or doing anything to interupt the
conditions under which you claim to hear differences.

Ludvic said


If you have a test for personal difference/preferences in cables,
poetry, music, novels and wine out with it. You'll make billions
selling it to the profilers who'll be spamming you and me till the end
of our days.
Maybe thanks to you they'll find out that , sadly,
I'm past interest in their favourite topics and stop trying to
titillate me in vain.
Ludovic Mirabel
I know that you're a serious guy but, please, for once give up.
Believe me; frustration only lies this way.


I have proposed such tests but I don't expect to make money off them. What I
proposed is not easy to do and not practical for the garden variety of
audiophile. Just becuase evidence hasn't been obtained does not make it
unobtainable.
  #25   Report Post  
ludovic mirabel
 
Posts: n/a
Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

(KikeG) wrote in message ...

Since everything I have to say has been said by me and others at least
a dozen times already. Since, I myself, (let alone the readers), am
bored to tears with the whole thing I'll try a dodge to hold my and
their interest for the next 15 minutes. We'll ask you to paeticipate
in an easy multiple choice test.
Two such signs mean "I said it".. One stands for "Kike said it."

I have no knowledge, opinion, interest in the particulars of such
research because it does not research differences between real-life
audio components.


Why not? I'd say that some do. Probably not available to the general
public, but some of them do.


Explain: A) Does "general public" to whom it is "not available"
include a) you b) me and c) our readers?
1) If a) is not a fact, please give me and your public the benefit of
reference; author, date, page
2) If all 3 (a,b and c) are true is the alternative of staying
silent when one has nothing to say;
2a) prejudicial to your cause?? 2b) too cruel to bear?

What I do object to is the belief that to "prove" your opinions re
"difference" or "no difference"- a necessary preliminary to
preference- (more about difference/preference in my answer to
Audioguy.) one has to undergo a procedure known as ABX.
Please, don't one of you tell me that "nobody says that".


I believe many people say that, and I agree. Or at least the need of
some DBT controlled procedure that doesn't have to be just ABX, it
can be an alternative procedure such as ABC/HR or others.
A simple answer: In a WELL DESIGNED AND PERFORMED TEST, ( my

capitals L.M.) there will be
NO DIFFERENCE due to the test. The thing is to design a test that
duplicates the listening habits of the listener, if that is neccesary,
but is made double blind. Maybe the listener will feel uncomfortable
with the idea of being tested, or with the idea that he may do "bad".
That's a problem of the listener (unless he is not aware he is being
"tested"), because those can't be addressed with this or with any
other possible test or evaluation procedure.


A) Is a "well-designed" and "performed" test
1) available on this earth?
2) available only in paradise?

3) paired with the Holy Grail?
3) available only in the objectivist dry (this is a family forum!)
dreams?

If number one is the case , please quote joutrnal, author, date, page.
If you are only now setting out to design it, do tell;
Will the "well-designed" test follow the model of the medical drug
research DBT and list the number and the selection of test subjects
(aka "population") for statistical significance, relevance to the
test's objectives etc.? Or will it be
A) just any old number of the average Joes from the street ?
B) "trained" subjects only?
Ba) by whom? Bb) for how long? Bc) who grants the "pass mark"? Bd)
what's the tolerable % of untrainables before the "test" is no longer
a useful tool for the consumers at large?
C) selected populations only? ; 1) orchestra musicians 1a) before they
have been there for long enough to lose their hearing?
2) Rock musicians? 2b)- ditto?. 2c) only the rock musicians who have
ever heard a piano and a violin? or 2d) only those who have heard
nothing but electronically amplified instruments ?
3) Autosound lovers?
3a) Only the "My "bass" is louder than yours" category or 3b) those
who play chamber music in their car (if you can find them)?
4) Middle-aged chamber music lovers? 4a) with? or 4b) without a
hearing test?
4c) male? 4d) female? 4e) a mixture? What proportions?
(On the average middle aged women keep their hearing better than men)
Would you like to continue or should we take a rest... ?

An ABX/DBT test introduces no biases, just removes them. The only
other biases that can appear will be due to the listener but not due
to the procedure.


Exactly. We listed just a tiny portion of the biases introduced by the
lsteners . Do you want to continue?

For Nth time, I think nobody has said ABX results have to be the way you say.
But if nodoby in earth has been ABX to nominally competent cables,
that means a lot.


I assume you meant to say: ‘But if nobody in the whole world has been
able to distinguish nominally competent cables when ABXing that means
a lot."

It would. But we don't have to ABX *everybody* on earth. The one and
only detailed, proctored and statistically valid available to me
cable ABX test is Greenhill's in The Stereophile, Aug. ‘83.( Know any
others?)
This is what Greenhill had to say: " Final significant conclusion one
can draw is that at least one "golden ear exists".
Why? Because this participant reached and/or surpassed Greenhill's
statistical criterion for a "hit"( minimum 12 out of 15 "corrects") in
5 out of six different cable comparisons. (SCORE 83%)
HE ALSO DISTINGUISHED CORRECTLY MONSTER FROM ZIPCORD OF SIMILAR GAUGE
WHEN PINK NOISE WAS PLAYED.
His one and only failure was when Monster was compared with zipcord
and MUSIC was played. Sort of interesting -see below-isn't it?
One other participant scored 66,7%.
Three (3) scored below random chance-33% hits.
Immaculately objectivist Geenhill reviewed the majority performance
and concluded : "We can only conclude therefore, that there is little
advantage besides pride of ownership in using these thick expensive
wires.

Who do you think was "right"?
A) The "golden ear'?
B0 The majority?
C) were they all "right" within their abilities and their
limitations.?
D) Was Greenhill right when he allowed his "golden ear"? or
E) Was he right when he said it didn't matter anyway?.
Not good taste and discrimination but majority rules. The decisions
which is the better instrument are decided by a public opinion poll.
(Lloyd "integrated" wins and ABX proves it by showing "no difference"
majority vote)

You ask:
Where is the evidence that difference in performance with music as
opposed to pink noise has anything to do with using an ABX-DBT
procedure? Nowhere.


Convincing, controlled
experiment with random control subjects etc. is missing.


That's an oxymoron, since there's no way to prove that without a DBT.


Oxymoron sounds nice. Let's see. You put on wide band choral music,
and sit down. A friend operates your stepped volume control in steps
of one db. up or down out of your line of sight.
No problem hearing the up and down 1db changes unless you're somewhat
deaf.and NONE hearing the 1.75 db changes as in Greenhill test that
73% failed when ABXed.

You now switch to ABX and can't tell the difference just like those
unfortunate ABX rabbits.

A) Should you have a hearing test? or
B) should you blame your friend or your equipment? Or
C) music for "making the test difficult"
D) or ask the ABXer nearest to you for HIS evidence that music doesn't
bother ABX and/or ABX doesn't bother music

If he tells you that it is up to YOU to provide such evidence,
because he doesn't like oxymorons, will you tell him to:
A) .......!!! or
B)!!!!.......??!!! or
C) or you will set about pronto to set up a "well-designed test" ,
finding participants, hiring the venue and the equipment and so on.
After all you can't keep the scientists waiting all these years ,
holding their breath.

If you agree that they would differ how do you justify YOUR
challenges to all and sundry to prove their perceptions by ABX.


ABX/DBT removes false positives, just that. It doesn't imply that
everybody should perform equally using ABX. Stop repeating that, please.


Sorry, being dense. Don't get too irritatated by me. If "everybody"
does not "perform equally using ABX" should your challenges be to
"everybody" or to the selected good performers only?

I'm not proopunding any "test". You are. I have
no faith to stick to. You BELIEVE in ABX. It is MY right to ask YOU
for evidence. And it is your job to give it.


It is proved that non-DBT tests are unreliable when it comes to
detecting differences and deciding preferences just from the actual
sound, and can't be trusted. It happens every day. So DBT is the only
way to go. Period. Show me any evidence against that.

I'm not in the "evidence" game because I don't have any "test" worth
bothering with. In secret: just to you: I don't believe you have
either. When I point out areas of doubt and flaws you say they can
only be dispelled by a DBT. And you call this nonsense " others'
oxymoron",
Quote references to "well-designed" component comparison tests
performed according to your "good test" criteria, and published in
the form readable on this earth. A test has to be shown to WORK for
its purpose. Not because Enrique sees no reason why it shouldn't, not
because it is like other tests which work in other fields with other
controls but HERE, NOW, comparing compoents.

In the meantime ponder what the piano virtuosi, violinists,
cello,viol, trumpet, clarinet players would say to you if you told
them that they must " prove" their personal instrument choices by a
DBT. I shall not list the choices this time. Why should just us , poor
audiophiles (that includes easily suggestible newbies) be so plagued?
Ludovic Mirabel



  #26   Report Post  
S888Wheel
 
Posts: n/a
Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

Tom said


Actually if nominally competent components such as wires, parts, bits and
amplifiers have never been shown to materially affect the sound of

reproduced
music in normally reverberant conditions why would ANYONE need to conduct
more
experimentation, or any listening test, to choose between components?

Simply
choose the one with the other non-sonic characteristics (features, price,
terms, availability, cosmetics, style...) that suit your fancy.


I said


That is the 64,000 dollar if.


Tom said


Examination of the extant body of controlled listening tests available
contain
enough information to aid any enthusiast in making good decisions. Even IF
the
existing evidence shows that wire is wire (and it does) how does that
preclude
any person from making any purchase decision? In my way of thinking it just
might be useful for a given individual to know what has gone before (and

what
hasn't.)



I said


Well, so far I don't see it the way you do. I must at this point thanl you
for
the articles on this subject you sent me when I asked for the alleged body

of
empirical evidence that prooved your position on the audible differences of
amplifiers.


Tom said


I said that a body existed. I offered to send you Some of the existing
evidence
because you said that you hadn't seen "any."


And I thank you again for doing so. Maybe you missed the part where I said "so
far" which was meant to imply that I haven't seen all the evidence to be seen.

I said


The "body of evidence" you sent me that constituted actual
evidence, raw data, was not much of a body. Only two articles out of the six
you sent had raw data ( "Can you trust your ears" by Tom Nousiane and "Do

all
amplifiers sound the same" by David Clark) and only the test you conducted
had
it in a usful table which could allow for the examination of trends such as
learning curves or fatigue curves.



Tom said


Let's be clear here. I did not offer to send you "the" body of evidence.
You'll
see "The Great Debate; Is Anybody Winning" a list of over twenty controlled
listening tests on amplifiers conducted prior to 1990.


Sorry for the misunderstanding. I didn't mean to imply that you have sent me
all the evidence that exists on the subject.

Tom said


As to raw data "The Great Chicago Cable Caper" and "To Tweak or Not To Tweak"
both contained raw data.


The copy you sent me of "The great Chicago Cable Caper" doesn't really address
the issue of the audibility of amplifiers. I mistakenly identified "can you
trust your Ears" with "To tweak or not to Tweak". "Can you trust your ears
contains no raw data.

I said


First, this is not much of a body of
evidence. Second, if we are to draw conclusions from the results we would
have
to conclude that some people can hear differences between amps and some amps
sound idfferent than some other amps.


Tom said


None of the raw data suggests that.


Sure it does unless you consider a 94% probaility that a difference was heard
to to suggest that no difference was heard.

I said


Of course it would be a mistake to draw
conclusions from those tests by themselves because they simply are not that
conclusive. If what you sent me is the best evidence out there and if what
you
sent me is any significant portion of the much talked about "extant body of
controled listening tests available" then I don't see how anyone can draw

any
strong conclusions one way or another.



Tom said


What is so funny is that I offered to send you copies of some data because
you
claimed to have not seen ANY of the approximately 3 dozen controlled
listening
tests that had been published in popular journals over the years. I didn't
offer to send you all data that exists.


Why is that funny?

Tom said


If you were truly interested you should do some of your own homework.


I have been. You sending me articles on test and me reading them and analysing
them is doing homework.

Tom said

But it
certainly doesn't seem that you do have a true interest.


You are entitled to your opinions about me. but it seems that they hinge on
whether or not I agree with you. that appears to me to be quite unfair and
unreasonable.

Tom said


And you're missing an important point; no one has produced a single
repeatable
experiment in normal listening conditions where nominally amps, wires or
parts
have been shown to have an audible effect.


It is only important if it is taken out of context. That context being the body
of repeatable experiments that have produced definitive nulls that have been
thouroughly and properly investigated when some results suggest that some
people may have heard differences and that some equipment may have sounded
different. Further,one cannot ignore the lack of controls of test sensitivity
when drawing conclusions. Unless you have demonstrated that under the given
test conditionas the listener can distiguish known barely audible differences
you have not eliminated the possibility of insensitivity on the part of the
listener in the given test or the inability of the system used to reveal such
differences.

Tom said


The ONLY existing evidence on your side for amplifiers is pcabx which uses a
overly sensitive microscope-like technique that doesn't represent the typical
sighted conditions where 'amp differences' are often made.


My side? The moment one takes sides they are in deep water IMO. My side, as it
stands, is I haven't seen relaible scientifically valid proof either way. I
have now seen two documented tests that never were peer reviewed and failed to
establish test sensitivity and had mixed results upon which no definitive
conclusions could reasonably be drawn.Yes I claim to hear differences between
amps here at home but I don't claim those are scientifically valid claims and I
can be wrong.


Tom said


So IMO, a person truly interested in maximizing the sonic-quality

throughput
of
his system simply MUST examine the results of bias controlled listening

tests
OR fall prey to non-sonic biasing factors, even if they are inadvertent.


I said


I examined the results of contained in the articles you sent me and do not
find them conclusive. Unfortunately four of the six articles you sent me had
no
raw data to examine and only offered conclusions.



Tom said


Again, all of them contained raw data except for the summary piece which
listed
over twenty reports that you can track down if you have interest.


Nope. Only the two articles had raw data. Sorry that I misidentified one of
them.

I said


Given the fact that the two
articles that did offer raw data drew conclusions that I find questionable i
have trouble feeling condifent about the conclusions drawn in the other
articles missing the raw data. So I find the evidence to date that I have
seen
less than helpful in purchase decisions.


Tom said


So you will reject any data that doesn't support your prior held conclusions.


I haven't "rejected" any data so far. I do have issues with the lack of testing
for sensitivity which leaves any null results open to different interpretations
but I have not rejested any data because It didn't support any of my
preconceptions. I haven't rejected any data in those two tests.

Tom said

I
figured that would be your position.


You are sadly mistaken about my position.

Tom said

Why not try to find ANY credible data that
does? Happy hunting.


If you consider the data you sent me I would suggest that a listener was
hearing differences and a piece of equipment was being heard as different with
a 94% probablity as credible then look no further. But I think the reasonable
analysis of those two tests would be that one cannot draw any strong
conclusions one way or another without follow up tests with those listeners
that seemed to be hearing a difference or those pieces of equipment that seemed
to be sounding different fom each other.
  #27   Report Post  
Darryl Miyaguchi
 
Posts: n/a
Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

On 5 Jul 2003 20:25:01 GMT, (Nousaine) wrote:

Actually in the ABC/Hr protocol any listener reliably rating the hidden
reference worse than itself has demonstrated SOME form of test or subject bias.
Ther eis no other explanation; either the protocol has some form of non-sonic
confounding identifier OR the subject can truly hear the difference and is
purposefully responding in a backward manner.


Typically the listener doesn't always pull down the slider for the
hidden reference, but does it once or twice out of a total of 5 or 6
groups. If the listener were to pull the reference for every codec,
or if he were to pull the reference for the same codec every time he
repeated the entire comparison (i.e., if it was "reliable" in some
way), I would certainly become suspicious.

I'm all for rejecting biased data but any kind of significant "reverse" results
shoyld be followed by an examination of the experiment to find whether it's
specific to a given subject(s). If the latter cannot be shown then the entire
experiment can be ruled invalid.


In one particular experiment, a listener was reliably identifying two
particular codecs out of six (he was able to do this for every one of
the music samples being listened to). This was very strange because
these were among the best codecs being compared, and he never
identified the one which sounded just awful to everybody else!

It turned out that this listener was picking out the two codecs based
on a difference in time alignment of about 25 milliseconds. Needless
to say, such a result would invalidate an experiment.

What I'm saying here in a roundabout way is that certain results raise
red flags, and usually there's a sensible explanation for what's going
on. A listener downrating the reference doesn't happen too often, but
it does, and I can't say that I'm all too surprised that some people
will do this, especially if they're relative novices at performing
this type of comparison. Unless somebody can come up with a better
explanation, I chalk it up to people thinking they hear a difference
when they really don't.

As I said earlier if you cannot determine that results were limited to a given
subject(s) then the whole experiment must be considered suspect. At the very
least it should be repeated.


One option is to ask the individual in question to repeat his test,
and I suppose this could be done for future comparisons. However, I'm
a very practical person. Pointing out a specific bias is one thing;
pointing out vague concerns about a possible bias with no plausible
mechanism in mind is another. Yes, some people could be downrating
the reference because of some as of yet unguessed reason. But I think
it's far more likely that they're hearing a difference that just isn't
there.

Darryl Miyaguchi
  #28   Report Post  
Bob Marcus
 
Posts: n/a
Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

(S888Wheel) wrote in message news:WMLNa.16609$I8.10056@rwcrnsc53...

I said I have never seen any scientifically valid empirical evidence on the
matter.You sent six articles only two of which had the raw data I was asking
about.The two that had raw data had not been published in a peer reviewed
scientific journal so they do not qualify as scientifically valid.


Huh? You seem not to understand the purpose of peer review. It does
not determine and is not the arbiter of "scientific validity." For
that matter, neither are you, though you seem to be claiming that role
here.

snip

What I find interesting is the best *evidence* you sent me on the matter was
IMO inconclusive. Some of the evidence in the Clark article suggested that
perhaps some people can hear differences and that some amps tested sounded
different to other amps tested. So how do you deal with that? Do you
acknowledge the test was inconclusive which is what I see or do you claim the
test gives us scientifically valid empirical evidence upon which we can draw
definitive conclusions?


Let's remember that ALL negative ABX results are inconclusive. That
doesn't mean they can't tell us anything.

snip

Wrong.In the Dave Clark test listener #2 got 30/48 correct with a statistical
relaibility of hearing a difference of 94% Listener #6 got 26/48 with a
statistical probablity of 84% chance of hearing differences. Listener #15 got
15/21 correct with an 81% chance of hearing a difference. Given the fact that
no tests were done to measure listener's hearing acuity and no tests were done
to varify test sensitivty to known barely aduible differences one cannot
conclude anything other than those listeners may have heard differences. Bell
curves have no meaning without data on the listener's hearing acuity. The
logicqal thing would have ben to do follow up tests on those listeners to see
if it was just a fluctuation that fits within the predicted bell curve or if
they really could hear differences as the results suggest. Hence there is no
conclusive evidence from this test that as you say"no single listener was able
to reliably identify amps under blind conditions.


I don't recall this article, but this conclusion seems to be well
supported by the data you cite. If the best performance of the group
wasn't statistically significant at a 95% confidence level, then it's
perfectly reasonable to say that no listener was able to identify the
amps in the test. (Note: Saying they couldn't is not the same as
saying they can't. As I noted above, we can never say definitively
that they can't; we can only surmise from their--and everybody
else's--inability to do so.)

Further more many different
amps were used in this test. If some do sound the same and some do sound
different this will have an affect on everyone's score and the bell curve.For
example a Counterpoint amp was compared to an NAD amp and the results of 30/48
correct answers with a probablity of 94% that a difference was heard. Yet no
follow up was done on this comparison.


Yeah, that's close enough that it might be worth someone's while to
redo the test. But the original researcher is under no obligation to
second-guess his own work. People who doubt that result, however, have
been free to try to replicate it for a couple of decades, I think.

That's how science works, my friend. You can't just stamp your foot
and say, "I don't find this conclusive!" You have to come up with a
new result. That nobody--nobody!--has come up with the slightest bit
of real evidence to cast doubt on that conclusion in all this time is,
while not conclusive, certainly revealing.

bob
  #29   Report Post  
Arny Krueger
 
Posts: n/a
Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

"Mkuller" wrote in message
news:hEENa.14984$I8.6569@rwcrnsc53

(Stewart Pinkerton) wrote:


Ludovic Mirabel, for instance, has posted thousands of lines of text
in various attempts to discredit what evidence exists to support the
notion that 'wire is wire', and that, by and large, 'amps is amps',
yet he has offered absolutely *zero* evidence to support his own
beliefs.


Obviously, your "evidence" is NOT sufficient to convince anyone (who
does not already believe) that "amps is amps" and "wire is wire".


This is an incredibly global statement that disqualifies itself simply on
the grounds of how unqualified it is.

Many people who once believed that amps mostly sounded different, have come
over to the "amps is amps" viewpoint, myself included.

It can be argued that the midfi audio market wouldn't exist if everybody
believed that all amps sounded different and only the really high priced
amps sounded good.

I would suggest that any "evidence" LM and those on the other side of
this debate would show YOU (or have shown you) would be insufficient
to convince you, since you have long ago made up your mind.


This statement ignores the existence of people such as Marcus, Nousaine and
I who were formerly in the " amps mostly sound different" camp.

So what exactly do you hope to accomplish by continuing this endless
"debate"?


Ask the people who start threads like this. The google record shows that
this thread was started with the following post:

http://www.google.com/groups?selm=bc...s1.newsguy.com

The author is clearly identified to be someone who is clearly AGAINST the
"amps is amps" viewpoint. This simple fact demolishes any argument that
might be made along these lines. It appears to me that some people need to
do their homework before posting.

Isn't one definition of "insanity", 'continuing to repeat
the same behavior, but expecting a different result'?


Case in point, I do believe!

  #30   Report Post  
Dick Pierce
 
Posts: n/a
Default Why DBTs in audio do not deliver

(ludovic mirabel) wrote in message news:n7IKa.24750$Bg.13287@rwcrnsc54...
(Dick Pierce) wrote in message news:KalKa.16012$R73.2926@sccrnsc04...
Well, the answer is VERY simple: DBT does not deliver what
people like Ludovic want. It does not support THEIR agenda,
it does not validate THEIR preferences, indeed, it does not
elevate their preferences to the level of universal fact.
Science certainly works hard to give you answers, it just
doesn't give a sh*t whether you like the answer or not.

What delicate feelings! what restraint! Only 3 letters out of 4.
THAT'S why DBT doesn't work: because it does.

Here comes the heavy artillery:
"SCIENCE' gives the answers. Mr. Pierce knows them. And I'm supposed
not to like them.
Exactly which answers to what?
CDs are "better" than lps.?
Transistors are "better" than tubes.?
Yamaha transistor amp. is "better" than VTL.?


Mr. Ludovic shows us here that he is in the "enviable" position
of not being constrained by facts or information. No, unlike the
rest of us in this universe, he gets to make his "facts" up. Indeed,
he gets to make "facts" up about other people as well. We see here
a classic existance proof of this.

HIS claim, which he makes VERY evident above, is that I "know"
that "CD's are better than LPs."

That's very curious, because I have never said that.

His claim is that I "know" that "transistors are better than
tubes.

That's very curious, because I have never said that.

His claim is that I "know" that "Yamaha transistor amp. is
better than VT: [sic]."

That's very curious, because I have never said that.

From whence does Mr. Ludovic achieve the ability, the privilege
and, indeed, the mandate to simply make stuff up and claim I or
anyone else "knows?"

There are several possibilities:

1. Ludovic occupies a unique and privilieged place in the world,
where he is privvy to information that NO ON ELSE knows about.

2. Ludovic simply made this stuff up.

In either case, it would seem that Mr. Ludovic has exempted himself
from the normal conventions of connecting claims about what others
think and know to what they actually think and know.

I shan't suggest this is anti-scientific or anything high-falutin'
like that.

I'd posit, instead, that Ludovic simply engages in a continuous
stream of misrepresentation. Why?

1. It's inadvertant. He doesn't no better. Poor Ludovic. Poor us
for having to slog through his irrelevant misrepresentations.

2. It's deliberate. He has no sound foundation for whatever the
hell it is he's arguing about and simply to keep his side of
the conversation going, he just makes stuff up because he has
absolutely nothing to contrinute of any relevance or substance.

The evidence, especially in the form of the quoted text above,
would seem to have one lean in the direction of deliberate and
malicious misrepresentation.

Frankly, I don't care. He has been one of the most voluminous
posters to rec.audio.high-end, and if you subtract the mis-
representations and the irrelevancies and the excess verbiage
and the seemingly unending repeations thereof, he is at the
same time one of the least relevant contributors.

Science, as in the process of advancing knowledge, could care less
about Ludovics' preferences. It has no feeling, has no agenda.

That's why DBT's don't agree with what Ludovic wants. It's not
supposed to. It ain't about picking Yamaha amps over VTL amps,
tubes over transistors, CDs over LPs, Stradivarii over Roland
synthesizers, despite Ludovic's misguided and continuously
unsuccessful attempts to force it into that utterly innapropriate
arena.

If science had feeling, it'd probably be laug

Answers from "measurements"? I let the scientists like yourself (and
eg. Mr. Atkinson of The Stereophile) argue as to exactly whose
"measurements" prove what.I understand enough to glimpse that people
with degrees in electronic engineering differ on those issues. Who am
I to decide whose measurements are "better"?
The sciences I am familiar with rely on experiment.
I know of none that provide "scientific", experimental evidence about
my preferences or yours.
And, dear Mr. Pierce, for lack of anything better I'm happy with mine,
do not ask you or anyone else to share them with me,(in fact I might
not even like it if you did) and certainly, most definitely do not
want or expect "scientific" support for them.
What on earth gave you the idea that I do?
Ludovic Mirabel




  #32   Report Post  
Dick Pierce
 
Posts: n/a
Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

(S888Wheel) wrote in message ...

Huh? You seem not to understand the purpose of peer review. It does
not determine and is not the arbiter of "scientific validity."


Perhaps you don't understand it. It more or less is such an arbiter
of such things. Any scientific claims that have not been through
peer review and publishing is regarded as junk science without
merit. Well at least according to the research scientists I have
asked. Maybe you know more about it than they do. In the world
of science when one does research via experimentation that
value of that data hinges on peer review.


The mere fact that a published article made it through peer review
does NOT mean that the reviewers agree with the contents of that
article. It simply means that the reviewers assert that the methods
used are up to standard. One can publish an article that describes
a set of well conducted, well researeched, carefully controlled
experiments that reaches a conclusion that disagrees completely with
the currently accepted scientific views, even the view of the peer
review committee.

This, at least, is the stated purpose and obligation of scientific
and peer review committees that I have been a member of.

Now, that being said, there are two levels of such standards in
organizations such as the Audio Engineering Society. The first
level, acceptance of papers for presentation at conferences and
conventions, allows for a much wider latitude. You have to have
screwed up pretty obviously for a paper to get rejected for a
session presentation. This is for a couple of reasons:

1. You only need present a precis or outline of your work, so
there is no opportunity for the review process before the
work is presented.

2. You will be giving the presentation live to an audience of
your peers. They WILL scrutinize it at that time and, should
you not have achieved a level of scientific quality suitable,
quite simply, you will be ripped limb-from-limb if you are
unable to plausibly defend your position.

The second level is the publication process. The full article
must be presented in its final form and is submitted to at least
3 reviewers. These reviewers evaluate the paper given a number of
criteria: suitability to the topic, quality of research, quality
of data, yada, yada yada, and then there is a shopping list of
specific criteria that must be met: proper use of standard units
and abbreviations, is the work of primarily commercial propmotional
content (it is rejected if it is), and so on.

But NOWHERE in the reviewer's guidelines is the criteria that the
reviewer must agree with the position of the author. The work must
stand on its merits. Once published, it is then subject to a much
more lengthy, careful, skeptical review process by the community as
a whole, and the success of the author's position is NOT assured
simply because the article is published. MANY articles that were
published have subsequently been show to have reached a wrong
conclusion, through more extensive research.

But S888Wheels' claim that the peer review process, to paraphrase
from the two sets of quotes above, is

"the arbiter of scientific validity"

is simply NOT the case. It is an assurance to the reader that, in
the opinion of the reviewers, the author took appropriate care in
the PROCESS, but THE PEER REVIEW PROCESS IS NOT A SANCTION OF THE
RESULTS OF THE AUTHORS METHODS NOR OF HIS CONCLUSIONS DERIVED
THEREFROM. All due respect to S888Wheels' scientific researcher
friends, someone is not understanding the process if they claim
otherwise.

Dick Pierce

  #33   Report Post  
Bob Marcus
 
Posts: n/a
Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

(S888Wheel) wrote in message ...
I said


I said I have never seen any scientifically valid empirical evidence on the
matter.You sent six articles only two of which had the raw data I was

asking
about.The two that had raw data had not been published in a peer reviewed
scientific journal so they do not qualify as scientifically valid.


Bob said


Huh? You seem not to understand the purpose of peer review. It does
not determine and is not the arbiter of "scientific validity."


Perhaps you don't understand it. It more or less is such an arbiter of such
things. Any scientific claims that have not been through peer review and
publishing is regarded as junk science without merit.


This is oversimplistic. There is plenty of good scientific research
conducted every day which never makes it into peer reviewed journals
for all sorts of reasons. (And I've seen some real garbage pass peer
review, too.) The mere fact that something didn't appear in a
peer-reviewed journal may mean nothing more than that the
peer-reviewed journals in the field weren't interested in that
particular topic. Frankly, I'm not sure any peer-reviewed journal
would be interested in whether there were audible differences between
a couple of consumer-grade amps.

Well at least according
to the research scientists I have asked. Maybe you know more about it than they
do.In the world of science when one does research via experimentation that
value of that data hinges on peer review.


Actually, its value depends on its replicability. Data which hasn't
been peer-reviewed may be replicable, and peer-reviewed data may not
be.

snip

Bob said

Let's remember that ALL negative ABX results are inconclusive. That
doesn't mean they can't tell us anything.

I was refering to the positive results in that test.


I got the distinct impression that there were no positive results in
that test. Isn't that what you were complaining about?

I said

Wrong.In the Dave Clark test listener #2 got 30/48 correct with a

statistical
relaibility of hearing a difference of 94% Listener #6 got 26/48 with a
statistical probablity of 84% chance of hearing differences. Listener #15

got
15/21 correct with an 81% chance of hearing a difference. Given the fact

that
no tests were done to measure listener's hearing acuity and no tests were

done
to varify test sensitivty to known barely aduible differences one cannot
conclude anything other than those listeners may have heard differences.

Bell
curves have no meaning without data on the listener's hearing acuity. The
logicqal thing would have ben to do follow up tests on those listeners to

see

if it was just a fluctuation that fits within the predicted bell curve or

if
they really could hear differences as the results suggest. Hence there is

no
conclusive evidence from this test that as you say"no single listener was

able
to reliably identify amps under blind conditions.



Bob said


I don't recall this article, but this conclusion seems to be well
supported by the data you cite. If the best performance of the group
wasn't statistically significant at a 95% confidence level, then it's
perfectly reasonable to say that no listener was able to identify the
amps in the test. (Note: Saying they couldn't is not the same as
saying they can't. As I noted above, we can never say definitively
that they can't; we can only surmise from their--and everybody
else's--inability to do so.)


That is ridiculous. If all of them scored 94% it would be reasonable to say
this?


If all of them had scored 94%, then we would have had a statistically
significant aggregate result. The fact that one of a panel of at least
15 did so is rather unsurprising. It's called an outlier.

No. It all depends on how they fall into the bell curve. but even this is
problematic for two reasons. 1. the listeners were never tested for
sensitivty
to subtle diferences. The abilities of the participants will profoundly
affect
any bell curve.


Sure, but is there any reason to believe this was a particularly badly
chosen panel? If a difference is audible, somebody in a randomly
selected panel of young to middle-aged men will probably nail it. I
gather from your report (remember, I don't have this article) that
nobody did.

2. many different amps were used. We have no way of knowing
that we didn't have a mix of some amps sounding different and some sounding the
same.


Aggregating data across different comparisons is meaningless. That
goes for individuals as well as panels, by the way.

The Counterpoint amp not only was identified with a probablity of 94% .
Given there wre 8 idfferent combinations it fell out of the predicted bell
curve if my math is right. Bottom line is you cannot draw definitive
conclusions either way. If the one listener had made one more correct ID he
would have been well above 94%. I doubt that one can simply make 95%
probability a barrier of truth. It is ridiculous. Bell curves don't work that
way.


But statistics DOES work that way. You have to specify your confidence
interval before you do your analysis. You can't say, "Well, he got
94%, and that's close enough."

Besides no follow up on any scores that push or cross the predicted the
outcome of the bell curve is an incomplete study IMO. now lets not forget the
failure to even test the test for sensitivty to subtle differences.


What subtle differences would you have tested for? Since we don't know
what it is that would distinguish these amps, how could we have
screened the panel in advance?

snip

Bob said

Yeah, that's close enough that it might be worth someone's while to
redo the test. But the original researcher is under no obligation to
second-guess his own work.


It isn't second guessing it is reasonable follow up on inconclusive data. No he
is under no obligation to do more testing but as the test stands anyone who is
trying to be scientific about this or even reasonable would have to acknoledge
that the tests as they stand are quite inconclusive. That is my primary
position on the data in those tests.


To repeat: ANY result that falls below the confidence level is
inconclusive. If you think some result is wrong, you need only
replicate the test.

Bob said

People who doubt that result, however, have
been free to try to replicate it for a couple of decades, I think.


My only criticism of the test itself is the lack of testing for listener and
system sensitivity. It would be a mistake to repeat that mistake.


By replication, we usually include efforts to improve on the test and
correct for methodological weaknesses, to see if we get a different
result. And now you've tossed in a second red herring: system
sensitivity. Care to define that and explain just how you'd expect the
researchers to "test" for it?

Bob said

That's how science works, my friend. You can't just stamp your foot
and say, "I don't find this conclusive!"


No foot stamping is needed. The test was quite inconclusive. Had the test been
put infront of a scientific peer review with the same data and the same
conclusions that panel would have sent it back for corrections. The analysis
was wrong scientifically speaking.


I thought we'd already agreed that you were unqualified to determine
what would and would not pass scientific muster.

Bob said

You have to come up with a
new result.


No. One does not have to do the test over to argue that the *conclusions* drawn
from that test are in eror.


Um, yes you do. At the very least, you need some conflicting data on
your side. Otherwise, you are merely talking through your hat.

One does not have to do a test over to point out
errors in protocol.


Errors in protocol do not automatically invalidate findings. They
merely suggest reasons why the findings MIGHT not be replicable. To
know whether they are indeed not replicable, somebody must do another
experiment, or at least find other, conflicting data.

The lack of testing for sensitivty lead the results open to
multiple interpretations. That is a fact.


That is a baseless opinion. You have offered no plausible reason to
doubt that either the panel or the equipment used was sufficiently
sensitive to produce reliable results. You haven't even defined in
measurable, technical terms what you mean by "sensitivity," let alone
offered a scientifically sound basis for claiming that any particular
level of "sensitivity" is necessary.

Bob said

That nobody--nobody!--has come up with the slightest bit
of real evidence to cast doubt on that conclusion in all this time is,
while not conclusive, certainly revealing.


Given that there seems to be an issue of interpretation of data, You are
welcome to yours as is Tom. Since I haven't agreed with such interpretations so
far I am only interested in the data. The data I have seen thus far on the
audibility of amps is inconclusive. Very inconclusive.


If so, then why is it that no one, in any university psychology or
electrical engineering department in the world, has published anything
on this subject in the last decade? Inconclusive science tends to
invite feverish research. And yet the leading experts in the field
appear to have no curiosity about this matter at all. Could it be that
they--who are a bit more expert in these matters than you or
I--interpret this data differently than you do? Could it be that
they're right?

bob

BTW: Would you be willing to return Tom's favor to you by forwarding a
copy of this research to me?
  #34   Report Post  
Nousaine
 
Posts: n/a
Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

Darryl Miyaguchi
wrote:

On 5 Jul 2003 20:25:01 GMT,
(Nousaine) wrote:

Actually in the ABC/Hr protocol any listener reliably rating the hidden
reference worse than itself has demonstrated SOME form of test or subject

bias.
Ther eis no other explanation; either the protocol has some form of

non-sonic
confounding identifier OR the subject can truly hear the difference and is
purposefully responding in a backward manner.


Typically the listener doesn't always pull down the slider for the
hidden reference, but does it once or twice out of a total of 5 or 6
groups. If the listener were to pull the reference for every codec,
or if he were to pull the reference for the same codec every time he
repeated the entire comparison (i.e., if it was "reliable" in some
way), I would certainly become suspicious.

I'm all for rejecting biased data but any kind of significant "reverse"

results
shoyld be followed by an examination of the experiment to find whether it's
specific to a given subject(s). If the latter cannot be shown then the

entire
experiment can be ruled invalid.


In one particular experiment, a listener was reliably identifying two
particular codecs out of six (he was able to do this for every one of
the music samples being listened to). This was very strange because
these were among the best codecs being compared, and he never
identified the one which sounded just awful to everybody else!

It turned out that this listener was picking out the two codecs based
on a difference in time alignment of about 25 milliseconds. Needless
to say, such a result would invalidate an experiment.


Well that was my point and it's gratifying that you take the time to examine
this form of bias.


What I'm saying here in a roundabout way is that certain results raise
red flags, and usually there's a sensible explanation for what's going
on. A listener downrating the reference doesn't happen too often, but
it does, and I can't say that I'm all too surprised that some people
will do this, especially if they're relative novices at performing
this type of comparison. Unless somebody can come up with a better
explanation, I chalk it up to people thinking they hear a difference
when they really don't.


Sure, that's a common human trait. But if they do this reliably then you need
to examine further for some form of bias.


As I said earlier if you cannot determine that results were limited to a

given
subject(s) then the whole experiment must be considered suspect. At the very
least it should be repeated.



One option is to ask the individual in question to repeat his test,
and I suppose this could be done for future comparisons. However, I'm
a very practical person. Pointing out a specific bias is one thing;
pointing out vague concerns about a possible bias with no plausible
mechanism in mind is another. Yes, some people could be downrating
the reference because of some as of yet unguessed reason. But I think
it's far more likely that they're hearing a difference that just isn't
there.


Darryl Miyaguchi


People hear non-extant differences of human nature. That's one of the ideas
behind statistical analysis. However, if they are reliably making these choices
then some form of non-sonic bias has to exist.
  #35   Report Post  
S888Wheel
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

I said


The copy you sent me of "The great Chicago Cable Caper" doesn't really
address
the issue of the audibility of amplifiers. I mistakenly identified "can you
trust your Ears" with "To tweak or not to Tweak". "Can you trust your ears
contains no raw data.


Tom said


Sure it does. You seem to want a subject by subject table. Why? It's all
enumerative data about Prefer A, Prefer B or No or Preference. I understand
your need to reject the data that subjects will gladly express a Preference
for
one of two identical sound alternatives 3/4 of the time. Live with that.


I just reviewed it again and found absolutely no raw data. in fact I found no
data at all. It does say the following "There wereno records kept" which looks
like the truth. Is my copy incomplete?

Tom said


None of the raw data suggests that.


I said


Sure it does unless you consider a 94% probaility that a difference was

heard
to to suggest that no difference was heard.



Tom said


That's the typical amp-difference response. Sift through the data and select
individual parts that seem to support one's position EVEN when they don't.


Funny, it wasn't my response in general it was simply my response if you insist
that the data be considered conclusive. I don't consider it conclusive and I
don't think it proved that soem or one individual could hear a difference. I
certainly don't think it proved the opposite.

Tom said


How about the below 50% data? You gonna overlook that? You can't have it both
ways.


No I didn't overlook that. I don't want to have it both ways. that is why i
find the results inconclusive along with a few other reasons that i have
already stated.

Tom said

At most, such examination (I do it too) might suggest further
experimentation but it doesn't 'suggest' that some amplifiers were heard.





Which is pretty much what I said. But, as I said, if you are to insist that the
data is conclusive one would have to conclude the Counterpoint and the NAD
sounded different and that there is a reasonable possibilty that one of the
listeners was reliably hearing differences. The data certainly suggests that
the Counterpoint and the NAD sounded different with 94% confidence. While the
evidence suggests this it certainly doesn't prove it. But you said that no
tests *suggest* this. Given one of the two articles that had raw data did
suggest the very thing you say it does not I would be more curious to see the
raw data on the 3 dozen or so other tests you have mentioned rather than see
anyone's analysis of them. Aside from the statistical analysis which saves me a
lot of work that I find difficult.



  #36   Report Post  
S888Wheel
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

It can be argued that the midfi audio market wouldn't exist if everybody
believed that all amps sounded different and only the really high priced
amps sounded good.


I think it would be a weak argument. there is no debate that speakers sound the
same yet, many midfi inexpensive speakers are chosen over more expensive
speakers that sound better to most listeners. Many people who believe that amps
sound idfferent opt for less expensive amps. Economics are a factor even in a
world where everyone believes everything sounds different and the more
expensive stuff is believed to be intrinsically superior.
  #37   Report Post  
Mkuller
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

(Nousaine) wrote:
Well that's the idea behind double blind testing; keep the subject and
experimentor from contaminating the results. But you're being unresponsive.
Why
hasn't some manufacturer, seller, enthusiast produced a single relicable
experiment verifying amp or wire sound?

You can reject my opinion, data and experiments and you're still left with no
positive data from the producer side of the fence. Why is that?


Ok, I'll bite. Here's why I think there is very little positive 'scientific
evidence' showing components sound different.

1. No one cares about 'proof' except the few who personally believe and want
to 'prove' there are NO audible differences.

2. Those who believe there are audible differences are happy to trust their
personal perceptions, regardless of the loud protestations of the few (mostly
here on RAHE) that their perceptions are misguided.

3. DBTs are the preferred method of the 'debunkers' and they usually show
null results because of the way the tests are conducted and the fact that all
of the results are averaged. DBTs do not duplicate the way audiophiles
ordinarily listen to music and compare components. (Please spare me the
arguements that DBTs only change the use of sight - they are also unnatural
because they require the listener to make a blind guess.)

4. Failing a DBT has not convinced very many people that "there are no
differences", just that they were not able to identify the differences they
normally hear under those specific DBT conditions.

So why haven't those folks suggested or designed a test that would show the
differences? I refer you back to No.1. above.

It's an endless loop just like the DBT debates here on RAHE!
Regards,
Mike

  #38   Report Post  
Nousaine
 
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Default Why DBTs in audio do not deliver (was: Finally ... The Furutech CD-do-something)

(S888Wheel) wrote:

I said

By certain persons I suspect you are including me. That is an interesting
question. Does such a body of evidence even exist? When Tom Nousiane made

his
offer of such evidence the body of evidence he offered was hardly

conclusive
about the audibility of amplifiers.


Tom said


Please don't make up things that I didn't offer.


Well here is what the record shows

"Tom said

Yes, of course. I have spent the time and money to acquire all I can about
listening tests and what they show. My copy of the Proceedings wasn't free;
so
are you expecting me to send you or Scott a free copy? I've done the same
formany. Just ask.

I said

Consider it asked.

Tom said

snail mail address please."

Maybe I am missing something but that looks like such an offer to me.


It looks like and was an offer to send you a copy of the individual article in
the Proceedings that was referent "The Great Debate: Is Anyone Winning".
Nowhere did it include anything else. But I did include 5 other pieces all of
which you simply ignore .... even though you (or anyone else) can produce a
single contrary experiment.

Tom said

You said you had never seen
ANY evidence about the audibility of amps, wires and parts. I offered to

send
you one such report. Indeed one of the ones I did send you lists a couple
dozen
amp experiments.


I said I have never seen any scientifically valid empirical evidence on the
matter.You sent six articles only two of which had the raw data I was asking
about.The two that had raw data had not been published in a peer reviewed
scientific journal so they do not qualify as scientifically valid. It was
nice
of you to send the six articles. Thank you. In light of the fact that I was
asking about *any scientifically valid empirical evidence that supported your
position on the audibility of amps*. My comments on the two articles that
actually had raw data stands. I don't recall any limmits of only one report.

Tom said


What I find interesting is that not ONE credible, replicable bias controlled
report verifying the audibility of nominally competent amps, wires or
capacitors in normally reverberant conditions exists. Not one.


What I find interesting is the best *evidence* you sent me on the matter was
IMO inconclusive. Some of the evidence in the Clark article suggested that
perhaps some people can hear differences and that some amps tested sounded
different to other amps tested. So how do you deal with that? Do you
acknowledge the test was inconclusive which is what I see or do you claim the
test gives us scientifically valid empirical evidence upon which we can draw
definitive conclusions?


Oh please. You said that no evidence was extant either way. Now you will
dismiss anything that seems contrary. WHy not just produce the body? I know why
.... because it doesn't exist. And yet you will continue to buy the Legend
without evidence. That's generally called Faith.

Have a good time harboring your beliefs. I hope you won't make decisions that
only make you feel better snd do not improve the sound quality throughput of
your playback system.

I said

This begs the question are some people
drawing definitive conclusions with less than adequate evidence to draw

such
conclusions? Do you think the two cited articles supply sufficient evience

to
draw any definitive conclusions about the audibility of amplifiers?


Tom said


Find a credible one that suggests otherwise, why don't you?


The article on the Clark tests certainly did suggest that some people can
hear
differences and that some amps sound different than others.


Actually only IF you already believe they don't and will accept only the
partial data that MAY support that conclusion. But why don't you acquire some
of the other reports I suggested?


I said

Do you
think the evidence in those articles qualify as scientifically valid bodies
of
empirical evidence? Do you think the issue of test sensitivity was
sufficiently
addressed in those tests based on the content of those articles?


Tom said


Yes. Definitely.


How? There was no scientific peer review. Are you going to ignore the
protocols
of the scientific world? I think issue of test sensitivity in both cited
articles were quite poorly addressed.


In what ways? What differences other than frequency response, distortion and
level do you reference? How were those verified?

So much so that one can draw multiple
conclusions from the results such as the listeners may have not been
sensitive
enough.


Oh sure that's the standard high-end response to reports of "they sound the
same to me" ...... YOU aren't sensitive enough and/or Your System Isn't Good
Enough. I'm guessing that your system isn't good enough either.

The setup may not have been releavling enough etc. A bad mistake IMO.

OK IS your system Good Enough?

I said


Unfortunately four of the six articles
you sent me had no raw data to examine and only offered conclusions.



Arny said


Would this have made a difference?


I said


It does to me when I am asking for empirical evidence. conclusions and
analysis
is not data. analysis and conclusions without the raw data is just opinions
IMO.


Tom said


The statemrnt about lack of data is simply not true.


Yes it is. Only two of the articles had the raw data.

Tom said

All the reports sent to
him contained raw data.


Straw man. I said "the raw data" which implies all of it. Only two of the six
did this. Heck some of the articles had no raw data.

Tom said

The other was a compilation of results from a couple
dozen previously conducted amplifier tests.


Right. They were an analyisis of data that was not presented in the raw. That
was exactly what I did not want as I already explained.


You made no "requirements" about Raw Data in the beginning did you? But if you
read all of them carefully everyone except "Great Debate" and "Can you
Trust...?" had individual subject responses depicted.

But why would you care? You aren't interested in what the evidence shows, are
you? If you were you'd already have gathered some of the evidence and/or
conducted a modest experiment or two yourself.


Tom said

All Mr Wheel has to do is look them
up.


As if this is an easy and cost free task. We've been down this road before. I
have been on too many fruitless Easter egg hunts on this subject. If those
claiming the existance of evidence cannot provide it than it is unreasonable
for them to expect me to go find it IMO.


Why not? I've been interested and 'found them.' Why do you get a reprieve?

Tom said


But again he originally suggested that no evidence on the matter, one way or
another, actually existed.


Baloney! Never suggested it. Cite your proof or withdraw the claim please. It
is a misrepresentation of anything I said or believe.


So you never said that "you" had never seen any data either way?


Tom said

At the very least one should recognize that plenty of it exists, that
interested parties have had public access to same over the past 30 years and
that you can't find a single experiment that supports the claimed audibility
of
amps and wires.


All I have done is ask to see it. To date not much has been shown to me and
what has been shown is hardly something one could base any definitive
conclusions upon. What you sent me did not prove your position at all.


It certainly didn't support that none of it was extant or wasn't available to
interested parties. But, even so, why do you continue to insist that 'amps
ain't amps' when the only data you have to examine strongly shows otherwise?

It just leaves you to shout 'no' with no evidence to the contrary.

Tom said



What's funny is that Mr Wheel examines the raw data and rejects the
conclusion
"no single listener was able to reliably identify amps under blind
consitions"
that the data clearly depicted.


Wrong.In the Dave Clark test listener #2 got 30/48 correct with a statistical
relaibility of hearing a difference of 94% Listener #6 got 26/48 with a
statistical probablity of 84% chance of hearing differences. Listener #15 got
15/21 correct with an 81% chance of hearing a difference. Given the fact that
no tests were done to measure listener's hearing acuity and no tests were
done
to varify test sensitivty to known barely aduible differences one cannot
conclude anything other than those listeners may have heard differences. Bell
curves have no meaning without data on the listener's hearing acuity. The
logicqal thing would have ben to do follow up tests on those listeners to see
if it was just a fluctuation that fits within the predicted bell curve or if
they really could hear differences as the results suggest. Hence there is no
conclusive evidence from this test that as you say"no single listener was
able
to reliably identify amps under blind conditions. Further more many different
amps were used in this test. If some do sound the same and some do sound
different this will have an affect on everyone's score and the bell curve.For
example a Counterpoint amp was compared to an NAD amp and the results of
30/48
correct answers with a probablity of 94% that a difference was heard. Yet no
follow up was done on this comparison.


Let's sort through the only evidence that Mr Wheel has ever seen and try to
find isolated stuff that supports his prior-held beliefs. Have a good time Mr
Wheel. Why not continue with the other 20+ experiments summarized in "The Great
Debate: Is Anybody Winning?"

Arny said

Bottom line, there are plenty of opportunities now to do your own
experiments, gather and analyze your own data, etc.


I said


1. That is irrelevant. Tom was claiming one could use the extant body of
evidence to make purchasing decisions. I was addressing that claim. 2. That
is
not neccessarily true. Unless if we are trying to limmit this to
scientifically
valid tests.


Tom said


I've been making high quality decisions based on this evidence for a quarter
century.


I believe you believe that.


Sure; and why would you think otherwise? Because I make my decisions based on
sound quality why would you decry them?

I said


So I find the evidence to date that I have seen less than
helpful in purchase decisions.



Tom said


Those who will not see and won'y examine historyt are doomed to repeat
historical mistakes


Something politicians should pay attention to. We are not talking history
here
we are talking evidence. If you can find fault with my analysis of the
evidence
that we have discussed please cite it and prove it.


Sure; ALL the Extant Evidence shows that nominally competent amplifiers are
completely tranparent in normally reverberant conditions to non-biased
listeners. Show me ONE experiment that even suggests otherwise.

  #39   Report Post  
Mkuller
 
Posts: n/a
Default Why DBTs in audio do not deliver

(ludovic mirabel) wrote
The topic is: "Does ABX work for comparing high-end components?"


(Bob Marcus)

wrote:
Yes.

It works because it's a test of *hearing*, and anyone who understands
how our hearing works (which ought to include any medical
professional, but perhaps I'm being presumptuous here) knows that our
hearing works independent of the *kind* of device making the sound we
are hearing.

If you know different, please tell us.


It never ceases to amaze me how obviously intelligent people (perhaps I'm being
presumptious here) can take such a simplistic position on this topic. If you
think a well-designed DBT comparing audio components using music is just a
"hearing test", then it's no wonder these debates go on and on the way they do.

Regards,
Mike

  #40   Report Post  
ludovic mirabel
 
Posts: n/a
Default Why DBTs in audio do not deliver

(Bob Marcus) wrote in message ...
(ludovic mirabel) wrote in message news:C7kOa.128448$R73.15582@sccrnsc04...
(Dick Pierce) wrote in message et...
(ludovic mirabel) wrote in message news:n7IKa.24750$Bg.13287@rwcrnsc54...

The topic is: "Does ABX work for comparing high-end components?"


Yes.

It works because it's a test of *hearing*, and anyone who understands
how our hearing works (which ought to include any medical
professional, but perhaps I'm being presumptuous here) knows that our
hearing works independent of the *kind* of device making the sound we
are hearing.

If you know different, please tell us.

bob


"WE" have made an important contribution to psychometrics,
understanding of philosophy, acoustics etc. "WE" are not
"presumptuous" one little bit. It just is not in our nature. Either
"we" make sense or "we" don't.
"ABX is a test of "hearing" and "Hearing works independent(ly) of the
"kind" of device making the sound..."
A few carping ABXers may object that a "test of hearing" has been
known and practiced for years under the humble name of "hearing test"
and that their beloved ABX involves also BRAIN functions we know
little about; like for instance a cortical centre for MUSIC
processing.
Others might say that a defence lawyer produces "sounds" and is
followed by a prosecutor doing the same. The juries and the judge then
compare the respective sounds for difference/preference and if they
find none the defendant walks
Language- what's that?
Ludovic Mirabel

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