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Topic: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluation (Read 98296 times) previous topic - next topic
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Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #275 –
The more important question would be whether anyone could replicate the actual hodge podge of tests.

Too much is being made of this "well done" undergraduate-level industry insider AES book report which does little more than continue to show that the push into hi-re$ ultimately rests on deceptive marketing ploys.

Quote from: Dr. Reiss's press release
Our study finds high-resolution audio has a small but important advantage in its quality of reproduction over standard audio content.

...and now some irony for our viewers:
Quote from: Jakob1863 on
[Meyer and Moran] didn´t issue a press release; instead they used sort of guerilla marketing in forums promoting their publication.

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #276 –
Must watch:


--> Is Most Published Research Wrong?
"I hear it when I see it."

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #277 –
Why must I know that the toothbrush I bought is "gluten free!"???

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #278 –
I'm sorry to bother you, omniscient highness. I will send a hundred PMs to all the other people next time instead.
"I hear it when I see it."

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #279 –
You must not have seen any similarity between your post, my last post and the general topic.  I suppose mine may also only be regional.

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #280 –
Ok, looks like AES is finally done with the website update, can now access papers selected by Reiss.
Started with the most recent non-BS-Under Review paper, by Mizumachi in 2015 Subjective Evaluation of In-vehicle High Resolution Audio.
Focusing on "trained" listeners (to hear what exactly?): 24/192 vs downsampled 16/48, 120 seconds music, 60 seconds silence, 120 sec music again. Order unclear (randomized???). In car system with woofer crossed to tweeter at 1k, supertweeters "added". At what frequency? Zero data there, or any form of distortion testing indicated. ::)
Looks like a whopping 76% "correct".
Same test, but now 24/192 vs 16/48 LAME converted to 320 MP3.
58% "correct".
WTF??
The trained listeners had a harder time with 320 MP3 vs 'Hi Rez" ?
Loudspeaker manufacturer

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #281 –
Quote from: greynol on
Why must I know that the toothbrush I bought is "gluten free!"???

There may be a similarity between gluten and the CD Audio format. Both are being indicted by unscientific and anti-scientific self-appointed authorities as being generally harmful. Yet, as a practical matter, both seem to be capable of  working  well, and both give most people a lot of enjoyment.

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #282 –
I am not so sure that the number of CD-rez-intolerant earpairs who need the extra mbits/s to hear the light of day, is comparable to the number of gluten-intolerant consumers. But if you put an infinite number of monkey scientists on a deserted island with a population to test each, then sure as hell there will be nonzero correlation in at least one of the studies.

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #283 –
Quote from: ajinfla on
Subjective Evaluation of In-vehicle High Resolution Audio.
I'm waiting for the paper showing a statistical analysis that supports the theory that in-vehicle hi-re$ audio affects a person's ability to drive safely.


...and the press release baldly claiming that hi-re$ audio provides small but important advantage in lessening your chances of getting into an automobile accident.

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #284 –
Swing the balance control wildly remotely and that will distract most drivers more than something they can't even hear in the first place.

For added fun: Put out frequencies that attract all the bats in town to attack the car and that might just cause an accident assuming you find a way to reproduce it loud enough and speakers that handle them frequencies correctly and some kind of ultrasonic bat call that pisses them all off.

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #285 –
Quote from: greynol on
...and the press release baldly claiming that hi-re$ audio provides small but important advantage in lessening your chances of getting into an automobile accident.
Something like this?
"Though the causes are still unknown and the effect is perhaps small and difficult to detect, the perceived fidelity of an audio recording and automobile playback chain is affected by taking a hypersonic bath while driving, leading to lower rates of accidents. Further, it has been found that training for these unknown causes has been shown to improve driving."

Any idea how to add a supertweeter to my car stereo like they had to, or why that would bring it closer to 320 mp3 SQ??

cheers,

AJ
Loudspeaker manufacturer
 

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #286 –
Quote from: greynol on
Did you make sure to include various degrees of artifacts from the "unknown" category to serve as positive controls like what was done in the BS "typcial" filter study?

As I've been studying their training strategy, additional concerns about its relevance have arisen:

Just to review, the actual transition bands used during the "...Typical Audio Filters..." paper were:

"The frequencies of the transition bands were 23500-
24000 Hz and 21591-{22050 Hz, corresponding to the
standard sample rates of 48 kHz and 44.1 kHz re-
spectively.4 Fig. 2 shows the amplitude and energy
of the impulse response for the 48-kHz filter.

Doing the arithmetic, the experiment used transition bands that were 500 Hz wide, when actual typical audio filters used transition bands that are more like 2-3Kz.  The consequence of a narrower transition bands is the generation of excessive and unnatural artifacts including variations in the far more audible bandpass (LF) region, and ringing at or near the Nyquist frequency (22 Kz).

However, things were even more asymmetrical with their listener training signals:

"
Listeners were able to
listen to as many labelled pairs of extracts as they
liked before progressing to the test. The filter used
here was an FIR filter with a frequency transition
band spanning 8-10 Hz. This filter was chosen as it
would have been straightforward for most listeners
to identify differences introduced by its application.
"

My early expectation was that the primary artifact due this very, very narrow transition band would be ringing, which relates to the experiment at hand. While I am continuing to study this problem (which includes teaching myself how to use Octave) my preliminary tests show that digital filters get really squirrely with transition bands this excessively narrow.   The primary artifacts turn out to be surprisingly broad  peaks and dips on the order of 2-5 dB in the bandpass region, which is to say the normal audio band going down to 1 KHz and below. 

I agree that these differences wold be "...straightforward for most listeners to identify..."  but these are not in the frequencies anywhere near the high frequency extensions that are provided by the usual so-called high resolution formats.  They are in a mid band frequency region where even mediocre DACs are flat +/- 0.1 dB or better.  They are not artifacts of the kind we usually relate to digital filters. 

While the article says:

"The second phase of training was intended to fa-
miliarise listeners with the fi ltering used and with
using the GUI."

Thus, the training that the listeners received was not relevant to the artifacts that were being studied.  There was no training that related to the filtering that the article purported to study.

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #287 –
Sounds like AES is just curating cash through membership fees.
EZ CD Audio Converter / FLAC or WavPack

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #288 –
Quote from: Arnold B. Krueger on
Doing the arithmetic, the experiment used transition bands that were 500 Hz wide, when actual typical audio filters used transition bands that are more like 2-3Kz.
One of the most common criticisms of the "...Typical Audio Filters..." paper, including one of yours, is that the filters are not really typical. This is a powerful criticism if one can validate it. But you also just throw out the word "typical" in the quote above. Can you state how you know this? Where does one find info on typical filters that are really used in the production of CDs?

I'm not so much interested in speculation about what they might use, but a true validation of the word "typical".

Thanks.

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #289 –
Quote from: bobbaker on
Quote from: Arnold B. Krueger on
Doing the arithmetic, the experiment used transition bands that were 500 Hz wide, when actual typical audio filters used transition bands that are more like 2-3Kz.
One of the most common criticisms of the "...Typical Audio Filters..." paper, including one of yours, is that the filters are not really typical. This is a powerful criticism if one can validate it. But you also just throw out the word "typical" in the quote above. Can you state how you know this? Where does one find info on typical filters that are really used in the production of CDs?

I'm not so much interested in speculation about what they might use, but a true validation of the word "typical"

The transition band of a typical DAC can be found in its spec sheet, either directly or by strong implication,  and can be measured using a number of different techniques that are commonly used to do frequency response measurements.  

I checked a number of Realtek PC audio chips  sepc sheets and found none, so I've had to measure some chips that I had on hand.  

The test method is simple - play a wideband frequency response test signal, such as an impulse, a swept sine (chirp), a multitone, or a swish, record it with known good ADC operating at a higher sample rate so that the ADC's filters don't interfere, and analyze.

Most other ADC and DAC chips spec sheets give a number for transition band or the companion specs for passband and stop band. The transition band is always between the two.

For example: http://www.akm.com/akm/en/file/datasheet/AK4430ET.pdf is a $0.50 chip with modest specs, and have the stop band and pass band specs on page 6. They are passband ending at 20-22 KHz, and stopband starting at 24 KHz for a transition band  of from 2-4 KHz.

This same info is presented for many competitive devices made by many other sources. Google is your friend.

At the end of the price spectrum we have:http://www.akm.com/akm/en/file/datasheet/AK4414EQ.pdf a high performance part running about $12.00, with very similar specs.

The pass, transition, and stop band are implements by digital filters  that are well-understood from the standpoint of implementation, and are just collections of well-known, inexpensive,  digital logic components (gates, etc).

The design parameters seem like common sense to me - run the pass band up to 20 KHz to do a good job of covering the audible range, and get the stop band fully blown  just above 22 KHz  to reduce spurious responses.   These same parts run at higher rates and some competitive parts have other optional pass and top band characteristics, to meet perceived needs.

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #290 –
The relevance of the “typical filters” paper in this thread relates to the ADC process, not the DAC, which is what you focus on in your last post. Once I have a CD or Hi-Res source, I can choose whatever DAC I want (50¢ up to ridiculous).

From the paper:
2.3 Signal processing and test conditions

([snip] filter parameters as you quoted [snip])

“These parameters were chosen to offer a reasonable match to the downsampling filters used in good-quality A/D converters or in the mastering process; we wanted to minimise the ripple depth and maximise the stop band attenuation in order to reduce audible ringing artefacts, as described by Lagadec [31].“

Do you have any relevant info on typical filters used in the production of CDs (as I originally asked)?
(Note: this sounds like a back-and-forth with Arny, but I hope anyone who might know would answer)

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #291 –
Quote from: Arnold B. Krueger on


I checked a number of Realtek PC audio chips  sepc sheets and found none, so I've had to measure some chips that I had on hand.  



Realtek DAC have their specs e.g here http://www.hardwaresecrets.com/datasheets/ALC898_DataSheet_0.60.pdf

and typical filter is - page 70 point 9.1.3 - for DAC 0,441*sample rate start and 0,6*sample rate stopband and for ADC 0,45*SR start 0,56*SR stopband (page 70). So yes those filters at the device (sound card) level are approx. 3-4 kHz "long".

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #292 –
These are the default settings used by a resampler (izotope rx) that is popular with mastering engineers:

(link to source page).

However, many mastering engineers like to tweak resampler settings to what sounds seems best to them.

For a working figure though, I'd go with the above.

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #293 –
Quote from: bobbaker on
Quote from: Arnold B. Krueger on
Doing the arithmetic, the experiment used transition bands that were 500 Hz wide, when actual typical audio filters used transition bands that are more like 2-3Kz.
One of the most common criticisms of the "...Typical Audio Filters..." paper, including one of yours, is that the filters are not really typical. This is a powerful criticism if one can validate it. But you also just throw out the word "typical" in the quote above. Can you state how you know this? Where does one find info on typical filters that are really used in the production of CDs?

I'm not so much interested in speculation about what they might use, but a true validation of the word "typical".

Thanks.
When you play back your cd you will listen to the DAC filter in interaction with the filter used for resampling. Your DAC may filter lower and may make the resampling filter less important.
For the legendary paper as i read it they went 192->44.1->192 for playback. You now have the sum of 2x ringing that gets thru full power. I'd also call that non typical.
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #294 –
Quote from: bandpass on
These are the default settings used by a resampler (izotope rx) that is popular with mastering engineers:

(link to source page).

However, many mastering engineers like to tweak resampler settings to what sounds seems best to them.

For a working figure though, I'd go with the above.
And this website as well. A lot of products to choose from.
http://src.infinitewave.ca/

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #295 –
Quote from: bobbaker on
The relevance of the “typical filters” paper in this thread relates to the ADC process, not the DAC,

Please let me review the title of the paper I quoted for your enlightenment:

"The audibility of typical digital audio filters in a high-fidelity playback system"

What is unclear about the word playback?

Are you not aware that playback involves DACs, not ADC's?

However, it is a moot point because the digital filters used in ADCs and DACs (it may surprise you) can be the same. 

The ADCs used in recording are many and varied. It would take a audited market survey to get data that was appreciably more assured than the information I have already provided.

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #296 –
Quote from: bobbaker on

Do you have any relevant info on typical filters used in the production of CDs (as I originally asked)?
(Note: this sounds like a back-and-forth with Arny, but I hope anyone who might know would answer)

For ADC's (like DAC's), you can just go to the chipmaker's sites and look at the datasheets yourself to see what typical is.

For instance, AKM ADC product info can be found here:
http://www.akm.com/akm/en/product/detail/0019/

Ti here:
http://www.ti.com/lsds/ti/audio-ic/audio-adc-technical-documents.page?viewType=mostuseful&rootFamilyId=376&familyId=581&docCategoryId=2

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #297 –
Quote from: bennetng on
Quote from: bandpass on
These are the default settings used by a resampler (izotope rx) that is popular with mastering engineers:

(link to source page).

However, many mastering engineers like to tweak resampler settings to what sounds seems best to them.

For a working figure though, I'd go with the above.
And this website as well. A lot of products to choose from.
http://src.infinitewave.ca/


Furthermore, a lot of recording production people use hardware-based  resamplers.  IME resampling hardware tend to use the same or similar filters as ADCs and DACs.

Absent an army of data-takers who skulk about a statistically significant number of recording sessions and production studios over the past 10 years and next however many years  doing detailed inspections of equipment digital filter designs, a question this complex will probably never be responded to by anything but informed speculation.

It seems like a simple reasonable question, but not so much.

It does beg the question of why a paper titled "The audibility of typical digital audio filters in a high-fidelity playback system" raised questions about ADC filter design in the first place, if not to create unnecessary ambiguity to help cover the tracks.

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #298 –
Quote from: Arnold B. Krueger on
Please let me review the title of the paper I quoted for your enlightenment:

"The audibility of typical digital audio filters in a high-fidelity playback system"

What is unclear about the word playback?

Are you not aware that playback involves DACs, not ADC's?
Amazing! To understand the paper, you must read more than the title. It is ambiguous… until you read the paper. You should! They are saying that:
“firstly, there exist audible signals that cannot be encoded transparently by a standard CD; and secondly, an audio chain used for such experiments must be capable of high-fidelity reproduction.” They clumsily combined these in the title, but reading the paper makes clear that the “typical” filters to which they refer are A/D filters.

Note, from the paper:
“Filter responses tested were representative of anti-alias filters used in A/D (analogue-to-digital) converters or mastering processes.“
“Experimental data are presented showing that listeners are sensitive to signal alterations introduced by two CD-like A/D filters and to 16-bit quantization with or without rectangular dither when the reproduction chain is of sufficient quality.”
“These parameters were chosen to offer a reasonable match to the downsampling filters used in good- quality A/D converters or in the mastering process;”
Quote from: Arnold B. Krueger on
However, it is a moot point because the digital filters used in ADCs and DACs (it may surprise you) can be the same.
It doesn’t surprise me at all. I understand anti-aliasing and reconstruction (anti-imaging) filters quite well. …unlike you… remember you confusion a year ago? I’ll avoid your “lessons” on filter use in sampling.
Quote from: Arnold B. Krueger on
The ADCs used in recording are many and varied. It would take a audited market survey to get data that was appreciably more assured than the information I have already provided.
Exactly! That is why I don’t trust the use of the word “typical” in the paper. But I also don’t trust your use of it. I can (and have) read many datasheets and understand that many options are available and therefore possible. But I don’t know what is “typical” and as you say, neither do you. It would be better if both you and Stuart’s group would avoid that term without better justification.
I do appreciate bandpass' answer though. He says izotope is popular, and that helps, but I'm still not comfortable with "typical".
Quote from: Arnold B. Krueger on
a question this complex will probably never be responded to by anything but informed speculation.

It seems like a simple reasonable question, but not so much.
I'm not asking a naively complex question without believing that your use of "typical" should mean you have more than speculation.

Re: Next page in the hi-rez media scam: A Meta-Analysis of High Resolution Audio Perceptual Evaluati

Reply #299 –
Quote from: bobbaker on
Quote from: Arnold B. Krueger on
Please let me review the title of the paper I quoted for your enlightenment:

"The audibility of typical digital audio filters in a high-fidelity playback system"

What is unclear about the word playback?

Are you not aware that playback involves DACs, not ADC's?
Amazing! To understand the paper, you must read more than the title. It is ambiguous… until you read the paper. You should! They are saying that:
“firstly, there exist audible signals that cannot be encoded transparently by a standard CD; and secondly, an audio chain used for such experiments must be capable of high-fidelity reproduction.” They clumsily combined these in the title, but reading the paper makes clear that the “typical” filters to which they refer are A/D filters.

Note, from the paper:
“Filter responses tested were representative of anti-alias filters used in A/D (analogue-to-digital) converters or mastering processes.“
“Experimental data are presented showing that listeners are sensitive to signal alterations introduced by two CD-like A/D filters and to 16-bit quantization with or without rectangular dither when the reproduction chain is of sufficient quality.”

It is a matter of not being confused by a lame attempt at proof by authority, as opposed to proof by means of reasoning, facts, and logic.

It has looked all long to many people for over a year that that the paper lost its way.

This was pointed out over a year ago in this discussion, which the authors were surely aware of and beholden to respond to:

https://secure.aes.org/forum/pubs/conventions/?ID=416

It's clear that the authors look at the title of this paper as window dressing:

"We do not agree with the comments relating to the introduction. The central question in this paper was to determine whether the addition of certain low-pass filters could be detected in an audio chain."

IOW Stuart finds nothing wrong with contradicting the title and introduction of any paper he writes.

So, when the Paper's abstract says: "This paper describes listening tests investigating the audibility of various filters applied in a high-resolution wideband digital playback system." the obvious face value of the English words are apparently not what is meant.

This reminds me of an old saying: "The British and the Americans are two peoples separated by a common language".

This ignores an obvious fact which is that recording and playback are very different operations. For one thing the consequences of recording is as it are one thing that is as it were, cast in cement.  If you redo or change it, you have a different recording.

This contrasts with playback, which is done a little differently each and every time it is done, a little differently for each listener even if for all practical purposes collocated and contemporaneous because listeners can't be colocated closely enough to be contemporaneous or in the identical acoustical location, within tolerances that are easily heard by ear. 

More significantly, it is possible and not infrequently that the identical converters and all other production equipment are identical are used for all published instances of a recording that exist, particularly shortly after the recording is made. However, it is generally accepted that every listener has his own choice of playback equipment which he generally can choose for himself.

Therefore focusing on choices of playback equipment that are made makes a lot of sense because many people do it of their own free will, and educating that free can change the quality of reproduction.

In contrast, the recording equipment and production equipment is what it was when the recording is made, and it is far less likely that the quality of the reproduction of recording can escape the limits that were set when it was recorded and produced at later time.

Thus the paper was interesting because of the contents of its title and abstract which were about playbad., Since the authors now say that they feel feel free to make their paper irrelevant and in some ways contradictory to their title and abstract, many go away after reading it feeling like they were cheated.