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Topic: Audibility of "typical" Digital Filters in a Hi-Fi Playback  (Read 367733 times) previous topic - next topic
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Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #200
This one found differences in the system they tested.  The outcome says nothing one way or the other about lesser systems.

Less expensive is not "lesser" system. It's less expensive. If it does not generate the artifacts of the DR beryllium domes speaker driven >105db without band limiting, it's far from "lesser" of a system, unless you mean "lesser" artifacts. Some of us who actually value fidelity prefer that. Less artifacts.

FYI, I passed all of my double blind ABX tests using my laptop and headphones.

Unsupervised, pointed out multiples times as useless and unrelated to the BS tests under examination, which were supervised and submitted to AES for review.

These points aside, if a very expensive speaker managed to do something everyday speakers cannot do with respect to bring out small differences in how the content was encoded, that by itself is quite significant.  That high-end hardware brings with it better resolution of audio and with it, potentially lend claim that if someone hears a difference on a high-end system and you cannot, it could very well be due to the system cost/performance.

A "high end" system that generates artifacts is not "better resolution". Be that speakers, amps or cables. Artifacts and distortions are not "better resolution".

So the cost difference is orthogonal to the discussion.

You just stated it wasn't for system costs. Now it is for content?

The other benefit is that you can download the high resolution master, but you cannot with the CD.

Benefit because the label offers downloads in every format but 16/44 WAV? They offer it in 16/44 FLAC, which is the equivalent of CD.
There is not a whit of evidence that any audiophile, anywhere, can hear any "benefit" with bigger files, in their system, in their room. Unless you mean "artifacts" like oil can resonances without band limiting. I certainly concede that possibility of "more resolution".

cheers,

AJ
Loudspeaker manufacturer

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #201
Benefit because the label offers downloads in every format but 16/44 WAV? They offer it in 16/44 FLAC, which is the equivalent of CD.

To the extent a high resolution file does exist, yes they do offer the downgraded versions.  Those versions however are not the CD master.  At least I don't think they are .

Quote
There is not a whit of evidence that any audiophile, anywhere, can hear any "benefit" with bigger files, in their system, in their room.

There is no evidence that they are not either.  So?

Quote
Unless you mean "artifacts" like oil can resonances without band limiting. I certainly concede that possibility of "more resolution".

You are talking about this in the stereophile review?

Although the tweeter's "oil-can" dome resonance results in a narrow spike 12dB above the reference level at 1kHz, this can be seen to occur at a high 26kHz.

So your contention is that people heard the 26 Khz resonance in the formal listening test?  What data do you have on audibility of 26 Khz AJ?
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #202
What type of dither did Meyer and Moran use?  Whatever was in the A/D and D/A converters of the CD-ROM recorder, right?  Here is Stuart on his latest test:

This [playback] level was
chosen for comfort, and because it was high enough
for details to be audible but also low enough that 16-
bit RPDF dither would be inaudible at the listening
position [30].


And

We chose to use undithered quantization as
a probe and | although we would normally rec-
ommend TPDF dither for best practice -- we con-
sidered rectangular dither to be more representative
of the non-ideal dither or error-feedback processing
found in some commercial A/D and D/A filters.


Seems reasonable to me.  After all, who knows what dither if any was used in the music that people are shipping to us in 16/44.1?  It is not like they know what you and I know about dither types.


So they calibrate the test for a particular system parameter but change that parameter during the actual test? And they give no citation to justify the change, but instead say "we consider"? This section should not have passed peer review (if it really did).

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #203
Quote
There is not a whit of evidence that any audiophile, anywhere, can hear any "benefit" with bigger files, in their system, in their room.

There is no evidence that they are not either.  So?

Seriously? Doh!
"I hear it when I see it."

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #204
So they calibrate the test for a particular system parameter but change that parameter during the actual test? And they give no citation to justify the change, but instead say "we consider"? This section should not have passed peer review (if it really did).

I don't follow you.  There is no system calibration.  There is no parameter change during the test.  The type of dither or not were independent tests.  The peers read the whole paper and not just that snippet. 
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

 

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #205
To the extent a high resolution file does exist, yes they do offer the downgraded versions.  Those versions however are not the CD master.

Downsampled, not "downgraded", which implies otherwise. This is end user product, so all that (should) matter, is the sound, not the "performance" or other weasel words that have nothing to do with end user sound that they hear.
I'll remind you amir, there is not a whit of evidence to suggest 16/44 playback is non-transparent in home audio end use.
Dubious dither doctored tests and unsupervised online games are not evidence against this.

There is no evidence that they are not either.  So?

Argument from ignorance. The onus falls on your "side" to present evidence of proof.

So your contention is that people heard the 26 Khz resonance in the formal listening test?  What data do you have on audibility of 26 Khz AJ?

Nope. My contention is that purported "experts" better look at all factors that may generate artifacts in the (human) audible range (<20k) when driving DR metal dome speakers near their limits without the benefit of 22K band limiting.
It would be a very amateur hobbyist type mistake, to overlook factors that create false positive results in any test. It's bad enough that one was deliberately introduced (RPDF) to induce positives. Overlooked ones might cause unnecessary embarrassment.

cheers,

AJ
Loudspeaker manufacturer

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #206
So they calibrate the test for a particular system parameter but change that parameter during the actual test? And they give no citation to justify the change, but instead say "we consider"? This section should not have passed peer review (if it really did).

I don't follow you.  There is no system calibration.  There is no parameter change during the test.  The type of dither or not were independent tests.  The peers read the whole paper and not just that snippet.


They said that the playback level was selected so that TPDF dither would not be audible (calibration) but then used dither known to be more audible (a change). There is no way to determine if the audibility difference is due to the known more audible dither, the higher resolution sampling, or a combination of both.

Doing something because it sounds reasonable to do so is not sufficient in a scientific test. Any test choice must be rigorously justified to insure that the stated hypothesis is actually being tested. The dither choice was not adequately justified. (I notice that they said "some" commercial filters in the text but in the abstract they say the filters were "representative" of filters used. Does "some" mean "representative"?)

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #207
We still have no idea whether any differences, supposing that they were detected reliably, were the result of the content or the hardware.

If it was the content (in the case of the Meridian test), we do not know what would have happened if the files had not been intentionally compromised with rectangular dither.

The only response that directly addressed the gist of my post was, "we don't know."

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #208
You are talking about this in the stereophile review?

No, as a speaker designer who deals with band limiting/suppressing breakup resonances with many rigid drivers.
But now that you mention it, I see there was a SP test of the 8000, the 7200SE obviously being a downgraded, lesser system version.


Quote
Although the tweeter's "oil-can" dome resonance results in a narrow spike 12dB above the reference level at 1kHz, this can be seen to occur at a high 26kHz. With CD material, this resonance will have no audible consequences, as it will not be excited by the band-limited source, even when upsampled by the Meridian 800. The resonance will be excited by wide-bandwidth SACD and DVD-Audio material, but I heard nothing untoward when using these sources.
-JA

The question is, if JA repeated the test in an iso-ward, with cherry picked and dithered material, then driven the speakers to near their maximum limits of 112db......would he still have heard nothing "untoward"? In a controlled, blind fashion of course.
Lot's of unanswered questions about this BS test. Including the transparency of the switching software, given the recent online fiascoes.

cheers,

AJ
Loudspeaker manufacturer

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #209
...
"We analysed the percent-correct scores for each of sections 1-17 across all conditions, and found that some sections yielded a higher ratio of correct results than others. For example, sections 2, 6 and 17 gave correct-to-total ratios of 0.714, 0.710 and 0.769 respectively, whereas sections 1, 7 and 10 gave correct-to-total ratios of 0.541, 0.455 and 0.509 respectively..."


Do I detect a faint aroma of fresh-picked cherries?
Or is it that... 
mmmm, fresh cherries.
Regards,
   Don Hills
"People hear what they see." - Doris Day

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #210
...
"We analysed the percent-correct scores for each of sections 1-17 across all conditions, and found that some sections yielded a higher ratio of correct results than others. For example, sections 2, 6 and 17 gave correct-to-total ratios of 0.714, 0.710 and 0.769 respectively, whereas sections 1, 7 and 10 gave correct-to-total ratios of 0.541, 0.455 and 0.509 respectively..."


Do I detect a faint aroma of fresh-picked cherries?
Or is it that... 
mmmm, fresh cherries.


Do they give the p-values for the data in each section?

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #211
I'll remind you amir, there is not a whit of evidence to suggest 16/44 playback is non-transparent in home audio end use.

AJ, you are typing in a thread where we are discussing an award winning, peer-review paper showing such differences can be audible.  The time for making that statement has come and gone.  You should look for other talking points, battles to fight.  This one is done.

Quote
Dubious dither doctored tests and unsupervised online games are not evidence against this.

I hear you.  You are wrong.  But I  hear you.  Buy the paper, read it and try again.

Quote
So your contention is that people heard the 26 Khz resonance in the formal listening test?  What data do you have on audibility of 26 Khz AJ?

Nope. My contention is that purported "experts" better look at all factors that may generate artifacts in the (human) audible range (<20k) when driving DR metal dome speakers near their limits without the benefit of 22K band limiting.

Demonstrate your point with measurements and data please.

Quote
It would be a very amateur hobbyist type mistake, to overlook factors that create false positive results in any test. It's bad enough that one was deliberately introduced (RPDF) to induce positives. Overlooked ones might cause unnecessary embarrassment.

Well, the odds are against a hobbyist like you knowing about these points than the luminaries in the industry and the peer review experts who awarded them the award.  But not impossible.  So make your case in detail without just claiming it AJ.

Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #212
We still have no idea whether any differences, supposing that they were detected reliably, were the result of the content or the hardware.

The thesis of the paper is neither.  Those were preconditions for the test.  The test hypothesizes that filtering from 192 khz down and conversion with or without dither may be audible.  And their listening test showed that to better than 95% confidence, they are.

Quote
If it was the content (in the case of the Meridian test), we do not know what would have happened if the files had not been intentionally compromised with rectangular dither.

Please demonstrate who the files were compromised with rectangular dither.

Quote
The only response that directly addressed the gist of my post was, "we don't know."

You asked a number of questions whose answer was that.  You were hypothesizing this and that and the answer is we don't know to all of that.  The core thesis of the paper we do know and I stated it again above.
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #213
Yes, and obvious flaws exist which were touched upon, which you have not been able to dismiss successfully.

If dither wasn't a problem, which hasn't been shown to my satisfaction*, then you're still left to contend with differences caused by artifacts in hardware/software; to which you also don't have a satisfactory answer.

So, sure, the thesis *may* have been supported by the results, but with severe caveats.

This isn't particularly earth-shattering when it has already been conceded that 16 bits is not audibly transparent under all circumstances.  I'm pretty sure most here will also accept that not all SRCs will guarantee transparency, either.

However, this topic is more about what people will attempt to make of the results and the predictable posturing they will take.

Did I get that right, krab?

(*) which will likely require independent verification with more complete transparency regarding the test conditions, which you are unable to provide at this point in time, so don't bother with this dead horse.


Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #215
Yes, and obvious flaws exist which were touched upon, which you have not been able to dismiss successfully.

Both statements are without foundation.  Anyone can declare anything like you are.  You need to make an attempt at a technical argument.  And as a minimum read the technical paper.  Not keep writing these information-free posts, passing judgement.

I know this topic.  I am in objectivity camp.  And I am telling that your case, our case, doesn't hold water.  There are no obvious flaws.  How would a paper with obvious flaws get the best paper award by peer review board of AES?

But sure, so that we actually discuss something technical, please in your own words state what you think is an obvious flaw.
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #216
This isn't particularly earth-shattering when it has already been conceded that 16 bits is not audibly transparent under all circumstances.  I'm pretty sure most here will also accept that not all SRCs will guarantee transparency, either.

I don't understand this tendency to use third party ghosts in such references.  Who are you speaking on behalf?  Let's have that list of people that agree with what you said.

And what do you think the lack of transparency will sound like?

And how do you know that is what was heard in Stuart's paper?  You have some back technical details to add to that or is that a generic assumption?

Finally, how come such understood problems did not get uncovered in Meyer and Moran?
Amir
Retired Technology Insider
Founder, AudioScienceReview.com

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #217
Ok, the paper is flawless and on solid ground.

So...

Rectangular dither doesn't matter because the noise floor on the 16-bit version was far enough below that of the listening environment over all frequencies.  This rules out quantization noise. So we're left with differences elsewhere.

Is this correct so far?

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #218
There is not a whit of evidence that any audiophile, anywhere, can hear any "benefit" with bigger files, in their system, in their room.

There is no evidence that they are not either.  So?
Talk about shooting yourself in the foot with a rocket launcher. Your failing to understand how to formulate a valid null-hypothesis puts any analysis of the paper in question in serious doubt. I didn't read the paper, yet, but if the authors use the same "scientific" approach we're done here.

To make it clear, the only meaningful, valid null-hypothesis is that all systems sound the same until proven otherwise.
It's only audiophile if it's inconvenient.

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #219
I think we have slammed the door shut on any statement regarding standing of this paper in the eyes of professional AES community.  It is excellent work.  It is the most careful double blind test of small differences due to coding of audio that has been published.  It is an inconvenient truth to be sure for many, but hopefully the search for knowledge and learning trumps that negative emotion.


It is tragic that such high accolades are being heaped on a document that libels and/or ignores well known previous technology (ABX testing, BS1116 recommendations, etc.)

The fact that the published document on the AES web site is apparently mislabeled speaks to excess haste and rush to judgement.

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #220
I am advocating getting the bits prior to remastering for CD.  Whatever was produced before conformance with the CD format and commercialization of music to teenage girls is what I want. 

I have said nothing about wanting higher frequencies than 20 Khz. 

And what I want is already happening.  What AJ wants, multi-channel music, is not.  I stated the market dynamics.  I know the business and technology side of the audio market.  You want to ignore the former, sure, go ahead but don't ask me to participate.
If I'm asking for anything, it's for reflection on this "why not" attitude. "Why not" get the "original bits" from the recording studio? If it were only that, who could object? Yet you allude to one problem already: because it drives the market towards a small or non-existent improvement, away from a real and easily audible one.

In the short term, that near-imagined improvement might be profitable for a small niche of the audio market. In the longer term, and for the rest of the market, it's a distraction at best, and a joke (making audio itself a joke) at worst.


It wouldn't matter so much if it was marketed and believed to be "just in case" as you claim here for the sake of argument on this forum. But we both know that's not the case: Some people are selling (and some people are buying) hi-res as the next big thing.


Quote
P.S. * = exaggerated for effect, but I think think you can still see the serious point here.

I did.  Disappointing to see word arguments rather that substantive discussion.
You ignored 12 sentences from me and kept 3 (even removing the most important one from the middle of them!). You can't be that disappointed at a lack of "substanetive discussion" otherwise you would have replied to it.

Cheers,
David.

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #221
Much of psychoacoustics/acoustics research is done with sighted analysis Arny.
If you really think that, get someone to buy you a subscription to JASA for Christmas.
http://scitation.aip.org/content/asa/journal/jasa

I don't know about all acoustic experiments, because some are hard or impossible to blind, but most psychoacoustic experiments have been routinely blind for nearly a century, and routinely double-blind since mechanised, and then computer controlled, and then fully computerised experiments became the norm.

Cheers,
David.

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #222
There are no obvious flaws.
http://robertwannamaker.com/writings/ieee.pdf
Page 31 figure 5 (b) shows the noise modulation due to rectangular dither.
Page 34 figure 7 shows the lack of noise modulation with triangular dither.

Wannamaker, Lipshitz, and Vanderkooy have spread this information, with varying levels of detail, across the world of audio since the 1980s. I am sure that the authors of the BS paper know and understand this information.

The BS paper accurately reports what they did, and tells you (at least partly) why they intentionally introduced this flaw into the test.

Saying "there are no obvious flaws" is just silly.

Cheers,
David.

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #223
AJ, you are typing in a thread where we are discussing an award winning, peer-review paper showing such differences can be audible.

Amir, save the "award winning" crap for your upside down DAC crowd, it's irrelevant here, where only the content of the BS paper is relevant. No one with a functional brain (my "side") has or would ever claim that 16/44 can't be made to be audible, any more than wires, caps or amps. That's the whole foundation of the your "side" of the industry, pathological audio, where everything that should be inaudible, is made specifically not to be, including digital.

Quote
Dubious dither doctored tests and unsupervised online games are not evidence against this.

I hear you.  You are wrong.  But I  hear you.  Buy the paper, read it and try again.

That is the entire basis of my analysis...and anyone else who can read. The BS paper deliberately doctored the test with RPDF to ensure positives. But there are other factors which may have created that result, none addressed in the paper - system transparency, switching software transparency etc, etc.
So there's no guarantee the deliberate dither doctoring was the actual cause of the positives.

Demonstrate your point with measurements and data please.

Demonstrate some logic please. Burden of proof is on the BS paper creators. It is they who must show (beyond the pathological dither) proof of validity.

cheers,

AJ

Loudspeaker manufacturer

Audibility of "typical" Digital Filters in a Hi-Fi Playback

Reply #224
It is tragic that such high accolades are being heaped on a document that libels and/or ignores well known previous technology (ABX testing, BS1116 recommendations, etc.)
Come on Arny, it's a good paper. It accurately reports the lengths they went to in order to get some barely significant results.

You can't blame the AES, or the paper's authors, for the frankly embarrassing way that amirm is lauding it about, or the way he's combining the results with some other seriously flawed tests to imply that hi-res audio is now easily and routinely ABXed.

Cheers,
David.