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Audio Empire Audio Empire is offline
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Default Pure Music to DAC - again

On Sun, 4 Sep 2011 09:30:45 -0700, Arny Krueger wrote
(in article ):

"Dick Pierce" wrote in message
...
Audio Empire wrote:

24 KHz is possible with DAT (48KHz sampling rate)


No, it is not. First, the Nyquist criteria requires
the bandwidth to be limited to less than half the
sample rate, not less than or equal to half. Second,
the transition bandwidth is not infinitesimal.


practically speaking, most DAT recorders had bandwidth
similar to CD players.


Except that CD players have a maximum sampling frequency of 44.1 KHz which
is set by the Red Book standard.

Let's not split hairs. while it is true that a 48 KHz digital signal can't
reproduce 24.000 KHz, it can reproduce 23 Khz, 23.5 kHZ, and in many cases
23.9 KHz. It depends, but many DACs don't have low pass filters that even
come close to totally obliterating the signal at 0.95 Nyquist, or at even
at the Nyquist frequency.

For example, the well-known Analog devices AD 1853 DAC

http://www.analog.com/static/importe...ets/AD1853.pdf

spec sheet says that its stop band is 26.23-358.28 KHz. 26 KHz is Nyquist +
2 KHz! According to Figure 14, its digital filter is only about 10 dB
down at 50 KHz with a 96 KHz clock. This is equivalent to being 10 dB down
at 24 KHz with a 48 KHz clock.



All of this is splitting hairs because I suspect that less than one person in
a thousand can hear those frequencies (that's a wild guess, it might be even
fewer than that). But my point stands. This falderall about high sampling
rates and wide digital pass-bands is mostly nonsense and puffery. The vast
majority of people don't hear frequencies above 20 KHz and what's up there
in the form of musical content is irrelevant. There is no real evidence (that
I have ever seen, anyway) that info above 20 khz has any effect on
frequencies below 20 KHz or even that the high frequency phase shift
introduced by some multi-pole filters is audible. Also, even though high
sampling frequencies such as 88.2KHz and above do push the quantization noise
high above the limits of human hearing, I have never seen any compelling
evidence that this is, in any way, audible either (of course, that doesn't
mean that it isn't, it just means that evidence isn't abundant enough to be
generally agreed upon in audio circles as being fact).

Now, having said that I have heard a particular analog master transferred to
so-called hi-rez digital that does, definitely, sound much better than this
same material on either vinyl or any of the CD releases of the same material
either on its native label CD transfer (done in the late 80's), a Mobile
Fidelity CD transfer (done in the 90's) or even on a JVC XRCD transfer (done
in the middle 2000's)!

In a blind test, everyone involved could always pick-out the HDTracks 24/96
version from the three CDs as sounding much better than any of the CDs. Not
particularly scientific, I agree, but it was so blatantly obvious whenever
the 24/96 file was played, that I don't think it would have made any
difference in the results had the test been double-blind. I.E, the listeners
couldn't tell which version was playing through the speakers at any one time
from any criteria other than how the playback sounded. All three were level
matched to the resolution of the HP 427A rms audio voltmeter, so, loudness
wasn't the issue. What I don't know is why the computer file sounded better
((lack of read errors, maybe?). There are simply too many steps involved in
transferring an analog master tape to digital (especially in three separate
CD releases done over almost 20 years) to say that the "hi-rez" file
(transferred in 2010, AFAICS) sounded best due to the fact that its 24/96.
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Audio Empire Audio Empire is offline
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On Sun, 4 Sep 2011 20:52:02 -0700, Harry Lavo wrote
(in article ):

"Robert Peirce" wrote in message
...
In article ,
Audio Empire wrote:

What I have noticed is less fatigue. This is totally subjective and
probably can't be measured. It is the difference between wanting to
listen to music all day and feeling forced to turn it off after a
couple
of hours. Some people may not even notice it.

But do you know for sure that's due to extended supersonic frequency
response?


Nope. I don't know what causes it. I just know that I notice it, and
it is very subjective.


Second that. Audible from the first day of SACD playback, and continues to
this day ten years later. CD's have become excellent, but I still can only
take a few hours of listening before becoming restless. SACDs can be
playing all day without this effect (and, BTW, so can analogue tapes).


Well, I "third" it, but I can only guess why. I certainly don't think it's
the increased bandwidth (at least I know of no phenomenon that would explain
such a thing). I also don't see how it could be the increased bit-depth (at
least in the case of 24-bit LPCM). It might be that audiophile-quality
recordings such as SACD and 24-bit, high-sampling rate downloads from the
likes of HDTracks, etc. don't undergo the heavy signal processing apparently
common in more commercial releases, and indeed, that was alluded to in the
Meyer/Moran paper on SACD vs 16/44.1. But they didn't go any further than to
mention that, generally, the SACD recordings that they used as a basis for
their study were better produced and did sound better than Redbook CDs. Other
than that, they did not elaborate.
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Andrew Haley Andrew Haley is offline
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Audio Empire wrote:

Now, having said that I have heard a particular analog master
transferred to so-called hi-rez digital that does, definitely, sound
much better than this same material on either vinyl or any of the CD
releases of the same material either on its native label CD transfer
(done in the late 80's), a Mobile Fidelity CD transfer (done in the
90's) or even on a JVC XRCD transfer (done in the middle 2000's)!

In a blind test, everyone involved could always pick-out the
HDTracks 24/96 version from the three CDs as sounding much better
than any of the CDs. Not particularly scientific, I agree, but it
was so blatantly obvious whenever the 24/96 file was played, that I
don't think it would have made any difference in the results had the
test been double-blind. I.E, the listeners couldn't tell which
version was playing through the speakers at any one time from any
criteria other than how the playback sounded. All three were level
matched to the resolution of the HP 427A rms audio voltmeter, so,
loudness wasn't the issue. What I don't know is why the computer
file sounded better ((lack of read errors, maybe?). There are simply
too many steps involved in transferring an analog master tape to
digital (especially in three separate CD releases done over almost
20 years) to say that the "hi-rez" file (transferred in 2010,
AFAICS) sounded best due to the fact that its 24/96.


It's easy enough to find out. Do a near-perfect downsample of that
24/96 file to 44.2 (easy enough these days in a digital audio editor),
resample it back up to 24/96, and see if anyone can tell the
difference. I'm sure PC/ABX would make it easy.

Andrew.

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Arny Krueger[_4_] Arny Krueger[_4_] is offline
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"Harry Lavo" wrote in message
...
"Robert Peirce" wrote in message
...
In article ,
Audio Empire wrote:

What I have noticed is less fatigue. This is totally subjective and
probably can't be measured. It is the difference between wanting to
listen to music all day and feeling forced to turn it off after a
couple
of hours. Some people may not even notice it.

But do you know for sure that's due to extended supersonic frequency
response?


Nope. I don't know what causes it. I just know that I notice it, and
it is very subjective.


Second that. Audible from the first day of SACD playback, and continues
to
this day ten years later. CD's have become excellent, but I still can
only
take a few hours of listening before becoming restless. SACDs can be
playing all day without this effect (and, BTW, so can analogue tapes).


Given that something like half of all SACD releases were just upsampled
and/or remastered transcriptions of analog and digital masters with bandpass
of 24 KHz or less...

In the absence of blind tests supporting these claims, it is there is a
finite probability that the restlessness observed is due to anxiety over not
keeping up with the latest in the emporer's new sample rates.

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Arny Krueger[_4_] Arny Krueger[_4_] is offline
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Default Pure Music to DAC - again

"Andrew Haley" wrote in message
...

Audio Empire wrote:


In a blind test, everyone involved could always pick-out the
HDTracks 24/96 version from the three CDs as sounding much better
than any of the CDs. Not particularly scientific, I agree, but it
was so blatantly obvious whenever the 24/96 file was played, that I
don't think it would have made any difference in the results had the
test been double-blind. I.E, the listeners couldn't tell which
version was playing through the speakers at any one time from any
criteria other than how the playback sounded. All three were level
matched to the resolution of the HP 427A rms audio voltmeter, so,
loudness wasn't the issue. What I don't know is why the computer
file sounded better ((lack of read errors, maybe?). There are simply
too many steps involved in transferring an analog master tape to
digital (especially in three separate CD releases done over almost
20 years) to say that the "hi-rez" file (transferred in 2010,
AFAICS) sounded best due to the fact that its 24/96.


It's easy enough to find out. Do a near-perfect downsample of that
24/96 file to 44.2 (easy enough these days in a digital audio editor),
resample it back up to 24/96, and see if anyone can tell the
difference. I'm sure PC/ABX would make it easy.


Not only is it easy, its been done by a number of folks, particularly
advocates for high resoluation recordings. The Hydrogen Audio Forum has been
a common venue for this sort of activity. Positive results are rare and when
they exist, they are generally traced to procedural errors.

One common procedural error is that people don't properly synchornize the
two recordings being compared. It needs to be done within a few
milliseconds. This can be tough, depending on the details of the experiment.
Another problem has been the use of an audio chain with excessive high
frequency nonlinear distortion. Another common problem is audible switching
transients that depend on the actual alternatives being switched between at
that instant.




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Robert Peirce Robert Peirce is offline
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Default Pure Music to DAC - again

In article ,
"Arny Krueger" wrote:

In the absence of blind tests supporting these claims, there is a
finite probability that the restlessness observed is due to anxiety over not
keeping up with the latest in the emporer's new sample rates.


I can't speak for others, but that isn't the case with me. At present,
my listening argument is limited to 44.1/16 and my observation is, on
the same equipment, recent releases are easier to listen to for long
periods than early releases. I don't want to drag SACD, HD downloads,
vinyl or tape into this because that opens a whole other can of worms

I am sure there were some great early releases as well as some terrible
recent releases. I am also sure the kind of music I am listening to at
any time is a factor. That is why I stressed that it is completely
subjective and may not affect anybody else but me. Apparently it does
affect other people but I can't say if the same thing is going on or not.

I would venture, without any evidence to support it, that whatever was
done to improve CDs probably has carried over to other media.
Consequently, if 96/24 sounds better or is just more comfortable to
listen to for long periods it could well be because of technological
advances involving digital mastering. In other words, I don't think a
96/24 recording of crummy material is going to sound any better because
it was done at 96/24.
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Arny Krueger[_4_] Arny Krueger[_4_] is offline
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"Robert Peirce" wrote in message
...
In article ,
"Arny Krueger" wrote:

In the absence of blind tests supporting these claims, there is a
finite probability that the restlessness observed is due to anxiety over
not
keeping up with the latest in the emporer's new sample rates.


I can't speak for others, but that isn't the case with me.


How do you know that for sure?

At present,
my listening argument is limited to 44.1/16 and my observation is, on
the same equipment, recent releases are easier to listen to for long
periods than early releases.


So far, I see no procedural controls that would make me believe that the
observed results surely have the stated cause.

You are still talking sighted evaluations, which have their strongest
supporters in the world of true-believer high end audiophiles. Remember,
sighted evaluations are the primary and generally only evidence for every
new and old example of audio snake oil.

I don't want to drag SACD, HD downloads,
vinyl or tape into this because that opens a whole other can of worms.


IME it is all the same can of worms - people are very likely to be acting
out their anxieties and beliefs if nothing is done to manage their effects.

I am sure there were some great early releases as well as some terrible
recent releases. I am also sure the kind of music I am listening to at
any time is a factor. That is why I stressed that it is completely
subjective and may not affect anybody else but me. Apparently it does
affect other people but I can't say if the same thing is going on or not.


I agree that it is impossible to find a relaible link between experience and
perceptions with the evidence presented so far.

I would venture, without any evidence to support it, that whatever was
done to improve CDs probably has carried over to other media.


I know of no signiifcant changes to how first tier audio production has been
done since the early 1980s that would seem to be an improvement in fidelity.
The major change since then has been decreasing costs for obtaining a given
level of quality and vastly increased use of digital at lower budgetary
levels.

Consequently, if 96/24 sounds better or is just more comfortable to
listen to for long periods it could well be because of technological
advances involving digital mastering.


Same story. I am also aware of large numbers of audiophiles who will say
that the aerage fidelity of recordings has only gone downhill since the late
1990s.

In other words, I don't think a 96/24 recording of crummy material is
going to sound any better because
it was done at 96/24.


Now, that is a known fact! No audible difference means no audible
advantage.


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Robert Peirce Robert Peirce is offline
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In article ,
"Arny Krueger" wrote:

"Robert Peirce" wrote in message
...
In article ,
"Arny Krueger" wrote:

In the absence of blind tests supporting these claims, there is a
finite probability that the restlessness observed is due to anxiety over
not
keeping up with the latest in the emporer's new sample rates.


I can't speak for others, but that isn't the case with me.


How do you know that for sure?


Because 44.1 is 44.1, or at least I believe it is. Are you suggesting
people doing CD mastering are slipping in higher bit rates and longer
word lengths than advertised and my observation is based on that? I
guess, if they are then I am, but I have no way to know that. As far as
I know, everything I am listening to was recorded at 44.1/16.


At present,
my listening argument is limited to 44.1/16 and my observation is, on
the same equipment, recent releases are easier to listen to for long
periods than early releases.


So far, I see no procedural controls that would make me believe that the
observed results surely have the stated cause.


And you aren't likely to. I would have to subject myself to several
hours of listening to bad CDs and several hours of listening to good CDs
without knowing which I was listening to or when they were recorded and
determine how long it takes before I want to turn them off. I'm not
sure that is a doable test.


You are still talking sighted evaluations, which have their strongest
supporters in the world of true-believer high end audiophiles. Remember,
sighted evaluations are the primary and generally only evidence for every
new and old example of audio snake oil.


As I said, without knowing. I don't formally keep a list of when a CD
was mastered. I have just noticed when I am listening to music I like
and I am not enjoying it, it is usually an older CD. That is not always
the case.

I am not disagreeing with the idea that bits are bits. My problem is
with what sometimes happens to the music before it becomes bits. Years
ago I had a preamp which allowed complete control of the playback curve
for an LP. This was from the pre-RIAA days. It was amazing how
different an LP could sound with different playback curves. I think
something like that (improper equalization) may have occurred in the
early days of CD, but of course, I don't know that.

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ligel ligel is offline
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Quote:
Originally Posted by Robert Peirce View Post
I run Pure Music on my Mac. Presently, I use Airfoil to send the signal
over ethernet to my AppleTV. The AppleTV has an optical output to my
DAC. Pure Music and my DAC both support 96/24, but the Apple TV only
does 44.1/16 (or, maybe, 48/16 - hard to find specs).

I have been trying to find a substitute for the AppleTV, but so far all
I have got is the Squeezebox Touch. I say "but" because it has its own
software that resides on the Mac and I have not been able to find out if
it can receive input from Pure Music or not. Does anybody know?

The web site suggests the Squeezebox can read any file on the computer,
which is great, except Pure Music already does that and allows many
useful manipulations. For example, it will accept up to 384/32 and
downsample it to 96/24. It will also upsample 44.1/16 to 96/24. Or any
other standard sample rate and 16, 24 or 32 bit words.

As far as I have been able to determine, the Squeezebox only passes
through what it receives, and that is great IF it can receive the output
from Pure Music. So, does anybody actually know if it can do that?

A related issue, but not critical, is that the software I am actually
running is Pure Vinyl. It is primarily designed for digitizing vinyl
recordings but it included Pure Music which I have grown to like a lot.
At present, I feed it directly from my pre-amp to the mic input on the
MAC, which works OK, but a two-way solution would be even better than
just using the player. Pure Vinyl can handle up to 384/32 if there is a
way to feed that to the Mac.
I have been using Pure music for a couple of months now. They and Amarra have free trials, so you can check out any differences yourself. I don't know of others that play like this through iTunes.

I can make a lot of comments. they may come slowly while I am at work.

1. Definitely both make a positive difference. Astounding really, but you don't realize how poor iTunes is until you try one of these programs. Amarra may be a little better sounding, but I didn't try that long because Pure music has a ton of features that Amarra doesn't, unless you perhaps get the $695 version. The "junior" and "mini" versions are so limited, you may as well buy Pure Music for $165 or so.

2. There are definitely bugs in the interface. you have lots of set up options and sometimes a small mistake will make something happen like not moving to the next track or something. I have multiple instances where there is a glitch in how the itunes interface works and I gets pulsating bursts of incomplete music. Always fixed with a reboot.

3. The sound improvement is definitely worth minor inconveniences like that above and the learning curve. There are many, many featurse and options and you can add modules or use the supplied ones to digitally modify, equalize or even cross overs. you can upsample, down sample and play native high sample rates. All good, if a little confusing. I am a fan of front end digital room treatment/equalization and this does that well. It has a limitation/oversight in saving equalization files, so you can lose data, but it sounds great and is very flexible. Audio hijack Pro has a better interface for this, but doesn't have the sound quality. It distorts a lot, this doesn't.

Overall, I highly recommend it! Amarra if you are a pro, but it is too expensive for me. Pure Music makes about the same difference as going from a lousy cheap DAC to an excellent high end DAC and you should do both.

For me, money well spent, but I hope there are user interface improvements, stability improvements and more options in the future.
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