[Audio_Empire[_2_]]

On Tuesday, December 11, 2012 9:43:23 AM UTC-8, Doug McDonald wrote:
On 12/10/2012 9:34 PM, Audio_Empire wrote:





Agreed. I don't know if this is true or not, but I have read that phase-shift at

or near the Nyquist cutoff frequency can have an effect in the audible range,

although no one has ever been able to explain to me WHY this might be so.







Sure they have ... I have, right here, and you agreed!



The answer is intermodulation distortion in tweeters.



Changing ringing characteristics can change this distortion.



I've been able to hear it, without a double blind test, very easily,

using several crappy tweeters at high levels. But in really good tweeters,

no, I didn't. This was many years ago ... I could redo the tests, but

I'd have to run the brick wall down to say 11 or 12 kHz.



Doug McDonald

I agree that phase shifts can cause distortion in tweeters, but I still don't see how 180 degree+ phase shifts up around 20 KHz (or higher) can cause AUDIBLE IM distortion in the passband,

[Audio_Empire[_2_]]

On Tuesday, December 11, 2012 3:56:43 AM UTC-8, Dick Pierce wrote:
Audio_Empire wrote:

On Monday, December 10, 2012 3:13:23 PM UTC-8, Sebastian Kaliszewski wrote:

You're ignoring the fact that part of that power is beyond the reach of

human ears. Squara wavee will produce more heat than same frequency sine

wave -- but that does automatically mean that additi0nal power would be

audible.



Yeah, but that's more due to the duty-cycle of the output devices than it is

power. wouldn't you say?



Two points: the "duty cycle" of a square wave, by any reasonable

definition of duty cycle, is the same for a square wave as a sine

wave.



Second, by definition, a square wave of a given RMS value will

produce EXACTLY the same heat as a sine wave (or ANY waveform of

ANY kind) of the same RMS value.



We're throwing a lot of pseudofacts around without apparently

understanding what we're saying.



What adds nice squareness for 7kHz wave on an osciloscope is well beyond

human hearing range. Hence that curvy thing at 7Khz which contains only

3rd harmonics (at 21KHz) will sound the same as something squarelike,

containng umpteen harmonics. Those higher harmonics won't be audible to

any human.



Agreed. I don't know if this is true or not, but I have read that phase-shift at

or near the Nyquist cutoff frequency can have an effect in the audible range,

although no one has ever been able to explain to me WHY this might be so.



What phase shift? I routinely look at complete A/D and D/A

systems (and by routinely, I mean several times a day) whose

phase shift across the entire audio band is within a VERY small

range. For example, I'm currently measuring one that's within

10 degrees to 20 kHz, and the only reason it's not that good

at low frequencies is because of the relatively small coupling

caps that result in it being 3 dB down at 12 Hz.

In the early days of CD (as I understand it), the analog filter
on the output was multi-poled. It had to be in order for
the signal to be 40 dB down (or whatever. I don't remember
exactly what the roll-off rate had to be to satisfy Nyquist -
Shannon) at the sampling frequency. Analog filters that
steep have more than 180 degrees of phase shift. Today
these filters are digital and can do 40dB/octave without
the phase shift of multi-pole analog filters (at least, so I've
read. I have no experience with digital filtering).



Look, people keep claiming this phase shift myth. It's not a

question as to whether large phase shifts near the Nyquist

frequency might be audible: you get to have that discussion

complete apart from reality, because the reality is these phase

shifts you're so worried about simple DO NOT EXIST.

Would it not exist in the vintage, first generation CD players
we've been discussing? I'm not saying that such phase shift
would be audible, just that such a phase shift would have to
be the result of using very steep sloped compound analog
filters. After all a gentle 6 dB/octave from a single-pole filter
wouldn't be sufficient, right?

[Audio_Empire[_2_]]

On Tuesday, December 11, 2012 8:02:57 AM UTC-8, Dick Pierce wrote:
Audio_Empire wrote:

On Sunday, December 9, 2012 7:58:24 PM UTC-8, ScottW wrote:

The point is that

square waves will show characteristics of an op-amp. That's why

most op-amp data sheets have lots of pictures (usually not photos)

depicting square-wave performance.



One further point, it should be noted that when I went and

loked up the slew rate performance of the various op amps in

my earlier post, not a single one of these figures was derived

from any pistcure or photos of square waves. Every one of the

slew rate figures was cleverly and carefully derived through

a special, proprietary algorithm I've developed that I call,

"looking at the slew rate specification." The data is

disguised in a very subtle fashion by the manufacturers, and

you have to know exactly where to look. For example, in the

spec sheet that Signetics published for the 5534, you'll see

it hidden in the line that says:



Slew rate: 13 V/us

Funny man! I don't remember specifically saying that square waves
are used in op-amp data sheets to show slew rate. As you say, it's
usually in the data sheet specification table. But square waves are
used on op-amp data sheets to show other things such as rise and
fall times.

[Dick Pierce[_2_]]

I just said:
Now, run a simple frequency response ("fr" to the uninitiated):
It will measure like crap: every 500 Hz, there will be a deep
null in the frequency response. Listen to this system with some
unusual signal like, oh, say, music: it will sound wierd beyond
description.

Sorry, I meant to type that there would be a deep null at every odd
multiple of 500 Hz, e.g., 500, 1500, 2500, ...

--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+

[Dick Pierce[_2_]]

Audio_Empire wrote:
On Tuesday, December 11, 2012 8:02:57 AM UTC-8, Dick Pierce wrote:

Slew rate: 13 V/us
Funny man! I don't remember specifically saying that square waves
are used in op-amp data sheets to show slew rate. As you say, it's
usually in the data sheet specification table. But square waves are
used on op-amp data sheets to show other things such as rise and
fall times.

Ah, that's because the rise time specs are similarily
disguised! For example, from the very same 5534 spec
sheet from Signetics, we have the very mysterious and
cryptic statement:

Rise time: 20 ns
Overshoot: 20%

WHatever could they mean by that, one wonders.

The point of my ironic sarcasm is that, in fact,
pictures of square waves in spec sheets ARE NOT there
to inform us of slew rate, rise time, overshoot or other
elements of performance. Such pictures are useless as
quantitiative informers of such performance specs.

The PRINCIPLE reason square waves have taken on such
significance in audio "performance" measurements is
because it's easy to generate, easy to see, but pretty
useless quantitatively. It tells you ABSOLUTELY nothing
that a properly done Bode plot will tell you and, in fact,
potentially tells you MUCH less. And, as a stimulus, it
if wholely unrelated to the actual conditions of operation
relevant to audio performance.

In another thread years ago on this very same topic, I
concocted an interesting gedanken to prove these points.
Consider a completely linear system consisting of two signal
paths through a system: one direct, one delayed by exactly 1
1 ms. The gains of both paths are identical and their outputs
are summed with an amplifier that itself has zero distortion
in both the amplitude and time domain.

Now, take a 1 kHz square wave, put it through such a system,
and observe its output: the result will be, within the limits
of the measurement device and the human's ability to assess
the picture on t6he scope, PERFECT square wave performance.

Now, run a simple frequency response ("fr" to the uninitiated):
It will measure like crap: every 500 Hz, there will be a deep
null in the frequency response. Listen to this system with some
unusual signal like, oh, say, music: it will sound wierd beyond
description.

Yet, it will have perfect square wave response under a number
of conditions.

So what?

Well, what it tells you is that square waves have extremely
limited utility AT BEST for characterizing a system. There are
plenty of reasons beyond what we discussed here, some of them
obvious, some of them subtely complicated and technical.

But those engineers who actually are engaged in designing real
high-quality, wide bandwidth equipment either do not rely on
square wave testing very much or simply do not use it at all.
There's MUCH more informative stuff around.

But, in a consumer add or to an "engineer" designing some
overpriced gold-plated piece of audio jeweelry that's more black
magic than science, they sure do look cool.

--
+--------------------------------+
+ Dick Pierce |
+ Professional Audio Development |
+--------------------------------+

[Andrew Haley]

Audio_Empire wrote:
On Monday, December 10, 2012 3:15:33 PM UTC-8, Arny Krueger wrote:
I was part of a DBT where two Hafler preamps were built as kits. One was
built totally stock. The other was built (by me) replacing every Mylar
capacitor in the signal chain with "Wonder Caps" and the two were
compared.

Documentation?

Why would there be documentation? This was an informal test between
a bunch of audiophile buddies.

I think that this points to language as one of the reasons why there
is so much misunderstanding here. When you talk about DBTs, people
think about a fairly formal kind of test with bias controls,
statistical analysis, and so on.

A friend of mine and I both bought Hafler DH-101 preamp kits at the
same time. He built his stock, I substituted the coupling and bypass
caps in the kit with Wonder Caps of the same value. At a meeting of
our little informal group of audio nuts, it was decided that we
would do a DBT of the two being fed the same signal (from a CD
player) and then feeding the same power amp (a MOSCode 600, IIRC)
through one of those Switchcraft surface-mount switches with the
three pairs of stereo inputs and one output. The speakers were a
pair of Magnaplanar Tympani-3C (all eight panels). Levels were
matched using an audio generator at 400 Hz and a Radio Shack digital
SPL meter and a VTVM. After a dozen of so tries everyone agreed that
there was definitely a difference and that unit #1 sounded
significantly less transparent than #2. No one knew which preamp was
which (you could only tell by taking the covers off the units).

But how could you stop them from knowing when Unit 1 was playing and
when Unit 2 was playing? And how did you prevent collusion?

Andrew.

[Scott[_6_]]

On Dec 11, 2:22*pm, "Arny Krueger" wrote:
"Scott" wrote in message

...
On Dec 10, 3:14 pm, "Arny Krueger" wrote:









"Scott" wrote in message

...
On Dec 8, 7:30 am, "Arny Krueger" wrote:

Given your stated position in this very thread on the lack of need to
control for same sound biases in ABX DBTs

Quotes?
"The above ignores a well known aspect of human nature
which is to strive for
a positive result from any activity that requires substantial effort.
An ABX test requires substantial effort on the part of listeners so the
listeners will *follow their human nature and strive for a positive result
simply because they are expending the effort and don't want the
outcome tobe futile."

Your conclusion does not follow from the quote.

Sure it does. We've already been over this. Not only is the above
quote factually wrong it was used as an excuse for the failure to use
bias controls in ABX tests against same sound bias.

*I simply pointed out The
existence of a bias to strive for positive results that I have observed in
real life. *Perhaps you would prefer that I not make an honest and complete
report?

Your report is quite anecdotal and filled with your own biases on the
subject. What you "pointed out" is in fact erroneous information on
the nature of human bias. And why did you "point it out?" was it an
arbitrary thought unrelated to the issue of same sound biases? It was
either that or an inference that same sound biases were defeated by
this erroneous claim about human nature. Anyway, it's already been
covered.


and given the well known biases of some of the folks who were involved
in
those tests

*Quotes?

You need quotes for that? Tell you what, you are the one with all the
back issues of Stereo Review.

I have no such thing. I don't believe that I have even one paper copy of SR
in my posession, nor do I know a priori where I might find such a thing.

1. So you don't have a copy of the article in question on the ABX DBTs
that Stereo Review did? The article you cited as evidence in regards
to the sund of those old CDPs?
2.Looks like we will have to go from memory. And as my memory serves
me, Stereo Review never used ABX DBTs in any of their product reviews
and yet always made the claim that CDPs and amplifiers and
preamplifiers all sounded the same. Their listening tests were all
done under sighted conditions for their product reviews. It's pretty
obvious that their biases were towards same sound.


Cite one review of any amp or CDP where
they do not make the claim that they all sound the same.

Where is the reliable evidence that the CDPs being discussed in SR at that
time actually sound different?

Why ask such an irrelevant question? Clearly people with a bias
towards different sound will detect non existent differences. Given
that Stereo Review did their auditions for their product reviews and
always claimed same sound for CDPs it is pretty clear they did not
have a bias toward different sound. We also know from the mountain of
evidence in psychoacoustic research that there is no such thing as a
person who has no biases. So the logical deduction is that they had a
bias towards same sound. I mean really, they didn't even do level
matched comparisons and we know the output levels of different CDPs
are, if nothing else, not exactly the same from player to player.
Still under sighted conditions they never ever thought they heard a
difference. The bias is pretty clear in this case.

And of course we have their own testimony as to what they
believed...Maybe JH secretly disagreed with everything he wrote in
Stereo Review? I don't think so.

[Arny Krueger[_5_]]

"Scott" wrote in message
...
On Dec 11, 2:22 pm, "Arny Krueger" wrote:
"Scott" wrote in message

...
On Dec 10, 3:14 pm, "Arny Krueger" wrote:

"Scott" wrote in message

...
On Dec 8, 7:30 am, "Arny Krueger" wrote:

Given your stated position in this very thread on the lack of need to
control for same sound biases in ABX DBTs

Quotes?
"The above ignores a well known aspect of human nature
which is to strive for
a positive result from any activity that requires substantial effort.
An ABX test requires substantial effort on the part of listeners so the
listeners will follow their human nature and strive for a positive
result
simply because they are expending the effort and don't want the
outcome tobe futile."

Your conclusion does not follow from the quote.

Sure it does. We've already been over this.

We disagreed then, we disagree now!

Not only is the above quote factually wrong

How can it be wrong? It relates something that actually happened. It relates
a well-known property of humans.

it was used as an excuse for the failure to use bias controls in ABX
tests against same sound bias.

No it wasn't. It was used to address a specific statement that I disagreed
with.

You seem to be forgetting my very strong accomplishments in the area of bias
controls relating to ABX tests.

Just to jog your memory, it has long been my position that there should be a
listener training program for each ABX test that is specific to that
particualar test. My recommended program is a series of tests involving the
same basic technical difference as the final test, but with the technical
difference augmented so that in the initial form, it is so easy to detect
that a person would have to be disqualified as a listener if they couldn't
hear it. The technical difference is then reduced in logical steps down to
the final level that is really the one that is most important.

If any listener is somehow biased against hearing the technical difference
in question, it will become obvious during the analysis of the various test
runs. His sensitivity will be far less than the majority of the listeners.

[Audio_Empire[_2_]]

On Wednesday, December 12, 2012 6:17:58 AM UTC-8, Andrew Haley wrote:
Audio_Empire wrote:

On Monday, December 10, 2012 3:15:33 PM UTC-8, Arny Krueger wrote:


But how could you stop them from knowing when Unit 1 was playing and

when Unit 2 was playing? And how did you prevent collusion?



Andrew.

That was fairly easy. At the time, the speakers were in my "listening room"
and the stereo components were in another room. The person doing the
switching was out of sight, and even she didn't know which preamp was
connected to which switch input. The listeners couldn't see the two
preamps or the person doing the switching, but they did know that one
of the two preamps had stock capacitors and the other had Wonder Caps.
So it was, I believe, truly double-blind.

[Audio_Empire[_2_]]

On Wednesday, December 12, 2012 6:21:47 AM UTC-8, Scott wrote:
On Dec 11, 2:22=A0pm, "Arny Krueger" wrote:
=20
"Scott" wrote in message
=20

=20
...
=20
On Dec 10, 3:14 pm, "Arny Krueger" wrote:

And of course we have their own testimony as to what they
=20
believed...Maybe JH secretly disagreed with everything he wrote in
=20
Stereo Review? I don't think so.

Actually, Julian Hirsch was of the "Yes, we have no opinion" school. His
reviews tended to consist of a physical description of the unit in question=
..
A discussion of the unit's feature set, and finally a series of measurement=
s
aimed at making sure the unit under test met its published specs. That's=20
generally all. If he listened to the unit, it was merely to confirm functio=
nality.
His conclusion was ALWAYS the same for every review and became famous:
"This (whatever piece of electronics he was testing), like all modern XXXXX=
Xs,=20
has no sound of it's own." The only time that he strayed from that non-opin=
ion
was when he was testing speakers, then he would give listening "opinions", =
but
even they were predictable: "The (speaker in question) had little bass belo=
w
about 60 Hz as it's frequency response test indicated."

[kronosav]

Originally Posted by Audio_Empire

In article ,
Trevor Wilson wrote:

On 11/28/2012 9:24 AM, Arny Krueger wrote:
"Trevor Wilson" wrote in message
...
On 11/24/2012 2:57 AM, Arny Krueger wrote:
"Trevor Wilson" wrote in message
...

I had a chance recently to audition, in my own system, the original
Sony
CDP-101 CD player. Boy is it god-awful sounding! Screachy highs, no
soundstage, in other words, downright fatiguing to listen to. It is,
however, built like a tank.

**I keep a CDP101 for people who imagine that all CD players sound the
same. It was, indeed, a shocker.

Absolute proof some people don't know how to maintain legacy equipment so
that it works and sounds as good as new.

**Fortunately, my business is service to audio equipment. I have the
service data, the techniques and test equipment to keep old CD players
(and most other audio equipment) meeting their original specs for many
years. Over the years, I've repaired several dozen CDP101 players. As a
consequence, I have built up a reasonable stock of the odd-ball parts
required for this model.


I have a CDP 101 that meets original spec and sounds great!

**I have a CDP101 that meets it's original specs (I use Sony test discs
and Pierre Verany test discs to verify Red Book performance) and it does
not approach the sound of a quality player like the Marantz CD80.

Since every sound quality problem has a measurable flaw at the bottom of it,
and since you claim that you have done thorough measurements of both
players, please explain your subjective opinons with the objective data that
you have.

**I cannot. The CDP101 meets (exceeds, actually) Red Book standards. It
meets it's own specs, as per the service manual. The Marantz CD80 does
likewise. I can't explain the audible differences that I (and 3 others)
heard during blind tests.

Have you acquired a Marantz CD80 to perform your own listening tests?


Since I have my own data, we'll see exactly how well you restored the CDP
101!

**Like I said: Refer to the published specs.

Since my opinion of the CDP-101 is essentially the same as yours, and
since someone else also made a similar observation about the CDP-101's
sound and add to that the fact that it was reviewed by several magazines
at the time as being of an audio quality that did not bode well for the
future of CD as an audiophile format, I'd say that the preponderance of
evidence suggests that the Sony CDP-101 was not a very good-sounding
player. I'm not sure what it says about the two posters to this NG who
insist that the CDP-101 sounds fine.

Hello Audio Empire,

I think the 16 bit DAC feature of this model may not be a good feature for SONY while designing the product. What do you think, if this will be a 14 bit encoding then it may sounds well?