Analysis of Paper on Measurements of RCA Cables by Kunchur (Video)

[Audiofire]

Funniest is the summary of the paper in the very first sentence
"Humans are uncomfortable with uncertainty and the unknown..."

 

[JSmith]

lol some of the arguments in that paper sound like those of a butt hurt individual!

Absolutely... a form for Kunchur & Jay to complete;

JSmith

 

[Palladium]

Funniest is the summary of the paper in the very first sentence
"Humans are uncomfortable with uncertainty and the unknown..."

Ah yes, the classic "tell me you don't understand basic science without telling me you don't understand basic science."

 

[René - Acculution.com]

If this is true you wonder about the quality of the peer reviewers invited by the AES: how can a publication like this pass the scrutiny of real experts?

For some journals, you are asked to suggest reviewers yourself, which of course can be good or bad. They may choose other reviewers than those you have suggested, but still, if you suggest reviewers that you have somehow made a deal with, it is obviously problematic, while on the other hand, if you are working in a particular narrow field, you likely know the, sometimes very few, people capable of fully reviewing your paper. I have sometimes gotten feedback from reviewers that clearly demonstrated that they did not fully understand the topic. I think that some reviewers give the articles a quick read-through, and if they are not experts in the field, they will not delve into much detail, if nothing immediately stands out, and just let it get out in the wild for the masses to judge. It can be very time-consuming to review, and it really should be. If you don't feel confident reviewing a paper, you should let the editor know, and just turn down the request to review.

For Kunchur, some signal processing issues are immediately evident, for example where he in the video shows some truncated sinusoidals, and presents them as signals of 440 Hz and 880 Hz, respectively, seemingly not realizing that there are infinitely many frequency components associated with finite-duration sinusoidals (see for example Communication Systems by Carlson). He also states in some paper that in general the frequency response is not capable of showing effects shown in the time domain, and demonstrates it by showing that the magnitude responses for a piece of music played forwards and backwards are the same, seemingly without realizing that the phase responses are different for the two situations, and since frequency response includes both magnitude and phase, it does indeed capture the time-reversal effect (look up Fourier Transform Pair of Time Reversal). His analogies also seem very constructed towards supporting his claims, without any real rigor to them. Finally, he seems fond of arguing ad hominem ("I have published, and you haven't, therefor I am correct, and you are wrong".), which typically makes for very muddy discussions that nobody really wants to engage in. Some actual okay points is his papers are entangled with no so correct points, and it takes a lot of time and energy to try and clear all of this up, since the problems span signal processing, acoustics, and hearing, and especially so when the author is not really receptive, and so it is easier to just give up.

When making single author papers, you have to be extremely self-critical, and not just let the official short-term peer-review determine whether or not what you are postulating actually makes sense, especially when going against well-established science. He should get a bunch of students to help him, and have some more collaboration going, such that the papers are vetted before the peer-review, instead of being questioned so much afterwards.

 

[SIY]

for example where he in the video shows some truncated sinusoidals, and presents them as signals of 440 Hz and 880 Hz, respectively, seemingly not realizing that there are infinitely many frequency components associated with finite-duration sinusoidals

Here's my problem- I'm not an expert but have a fair grasp of his main work in solid state physics. Fourier analysis is fundamental (literally, on Day 1 of any intro course in solid state, you cover representations in k space) and he clearly understands it on a professional level.

Which leads me to conclude that he absolutely realizes this and is deliberately misleading his audience. It's not ignorance, it's dishonesty. I find this absolutely reprehensible.

 

[René - Acculution.com]

It could be, I am not sure, but I get the feeling that he believes what he writes. Granted, it is a video, and not a journal paper, but he uses this example in a recent audioXpress article http://boson.physics.sc.edu/~kunchur//papers/Hearing-and-Audio-Part1--Freq-phase-and-time.pdf, without any more clarification.

 

[SIY]

It could be, I am not sure, but I get the feeling that he believes what he writes. Granted, it is a video, and not a journal paper, but he uses this example in a recent audioXpress article http://boson.physics.sc.edu/~kunchur//papers/Hearing-and-Audio-Part1--Freq-phase-and-time.pdf, without any more clarification.

I hadn't seen it and I wish I'd had a chance to review it before publication. Since his basic errors have already been pointed out and he is clearly aware of them, continuing in that vein while deliberately ignoring the criticisms makes the dishonesty particularly egregious.

 

[René - Acculution.com]

I hadn't seen it and I wish I'd had a chance to review it before publication. Since his basic errors have already been pointed out and he is clearly aware of them, continuing in that vein while deliberately ignoring the criticisms makes the dishonesty particularly egregious.

Yes, I agree; you cannot just continue down the same road with this amount of negative 'reviews'. I write a lot for audioXpress, and I may contact them regarding this. It is too late now, though, as it is out, but perhaps more articles are planned with him. I don't think my aXp articles are reviewed as such, but the peer-reviewed ones that he has out now are also of poor quality.

 

[DLS79]

Here's my problem- I'm not an expert but have a fair grasp of his main work in solid state physics. Fourier analysis is fundamental (literally, on Day 1 of any intro course in solid state, you cover representations in k space) and he clearly understands it on a professional level.

Physics majors (I was one), are taught how to write their own FFT algorithms! The side effect of having to write your own is gaining a strong understanding of the underlying concepts.

 

[ctrl]

Since his basic errors have already been pointed out and he is clearly aware of them, continuing in that vein while deliberately ignoring the criticisms makes the dishonesty particularly egregious.

@René - Acculution.com , thank you for the link.

After reading the Audioexpress magazine article, I tend to the same conclusion as @SIY .
Individual phenomena are correctly listed, only to be amalgamated into a sort of "secret esoteric audio doctrine" through knowingly false conclusions.

A few examples:

1. Two short sinusoidal tones/pules (440Hz and 880Hz) summed without time delay sound different than with time delay. Problematically, there is no indication (neither in the video nor in the Audioexpress article) of how large this time delay must be to be perceived.

In his example (C), mentioned in the article and played in the video, it was about 15ms, equivalent to over 5m (200in) difference in travel time - see details in post#514.

Now comes the esoteric part, where he links the above phenomena with the depth offset of drivers in non high-end audio (HEA) speakers and says:

"Indeed, many loudspeaker designs try to ensure that the acoustical centers of the drivers are equidistant from the listener, to correctly reproduce the timings between frequency components...
Thus, a time delay between onsets is more serious than phase mismatches, and as mentioned earlier, many HEA loudspeaker designs pay careful attention to this."

Unfortunately, the time difference between two drivers in a speaker rarely exceeds 0.1m at the listening position (even when the speaker is aligned to the tweeter axis).
His example uses a time delay at least 50 times larger than what occurs in speakers, which renders his entire argument absurd.


2. Listing facts that have nothing to do with HEA speakers (or audio) at all:

"The auditory binaural timing acuity is 10µs at 700Hz, which is a hundredth of the period T=1.43ms; also the acuity is 10 times worse (>100µs) at the higher frequency of 1400Hz!"

Some completely misunderstand this and then relate it to depth offset or phase shift between speaker drivers on a baffle.

For this to be relevant, one would have to lay the speaker on its side and remove one driver so that the left ear primarily hears the left driver and the right ear primarily hears the right driver (normally headphones are used), then the time difference in flight time would be relevant with specific signals and binaural timing acuity comes into play (if I got this right) - something completely different and not relevant for a single speaker inter driver off-set.

If this had any relevance when listening to music, one would have to listen with a fixed head, as the distance from ear to speaker and the distance ratio L to R constantly change


At the beginning of the article, Professor Kunchur writes:

To what extent the claimed improvements can be heard is questioned because their audibility has often not been confirmed by controlled blind tests. For these collective reasons, HEA is surrounded by considerable controversy and skepticism. However, some of this skepticism is based on misconceptions about the link between time and frequency domains, and a lack of understanding of how hearing works.

The problem is not that people do not understand or doubt the listed psycho-acoustic phenomena, but rather the lack of evidence of their relevance in HEA (high-end audio) products as correctly stated by Professor Kunchur and his article doesn't change that (at least the part related to speaker, where I'm a little familiar with).

 

[olieb]

It could be, I am not sure, but I get the feeling that he believes what he writes. Granted, it is a video, and not a journal paper, but he uses this example in a recent audioXpress article http://boson.physics.sc.edu/~kunchur//papers/Hearing-and-Audio-Part1--Freq-phase-and-time.pdf, without any more clarification.

I don't think he actually can believe what he writes.
Kunshur's paper you link hinges totally on the classic "result" of Leshowitz about the differentiation of two 10µs-pulses 10µs apart versus a 20µs-pulse.
Kunshur readily claims that this is due to the time resolution of hearing.
But if you look into Leshowitz' paper that is not only a false conclusion but Leshowitz analyses and investigates in great length that this discrimination is by all means is a result of the different spectral energy content of the signals.

You cannot cite Leshowitz and ignore that result, that is dishonesty in the crudest form.
And of course without this false conclusion the whole point of Kunshur's paper is moot. No surprise here.

Leshowitz paper can be read here: https://vdocuments.mx/measurement-of-the-two-click-threshold.html?page=1
For convenience two snippets that make the thing quite clear.

 

[ctrl]

You cannot cite Leshowitz and ignore that result, that is dishonesty in the crudest form.
And of course without this false conclusion the whole point of Kunshur's paper is moot. No surprise here.

Thanks for the link to the Leshowitz paper.
Full agreement!

It is downright ironic that Professor Kunchur emphasizes in the article how important the consideration of the time domain is for high-end audio (HEA), citing the "Two-Pluse threshold" as an example, where the time offset of the pulses due to phase shift ultimately leads to a change in the amplitude frequency response, making the effect audible. So, one does not hear the time delay itself, but its impact on the amplitude.

This also clarifies that the phenomenon of the "Two-Pluse threshold" mentioned by him cannot occur in speakers with drivers offset in the z-direction, aka not time-alignment speaker.

Because theoretically, this can only occur in the region of the crossover frequency. Only there can an identical impulse be played by both woofer and tweeter.

For this time delay to be audible, there must be cancellation in the amplitude frequency response (Leshowitz's hypothesis from the paper, why 10µs impulse delay was audible), which precisely is avoided at the crossover frequency with the commonly used all-pass filter which result in a flat frequency response. The filter compensates for the z-axis offset of the two drivers relative to each other.
At the listening position the driver off-set has no audible impact on the frequency response, so the off-set is not audible.

 

[Endibol]

For some journals, you are asked to suggest reviewers yourself, which of course can be good or bad. They may choose other reviewers than those you have suggested, but still, if you suggest reviewers that you have somehow made a deal with, it is obviously problematic, while on the other hand, if you are working in a particular narrow field, you likely know the, sometimes very few, people capable of fully reviewing your paper. I have sometimes gotten feedback from reviewers that clearly demonstrated that they did not fully understand the topic. I think that some reviewers give the articles a quick read-through, and if they are not experts in the field, they will not delve into much detail, if nothing immediately stands out, and just let it get out in the wild for the masses to judge. It can be very time-consuming to review, and it really should be. If you don't feel confident reviewing a paper, you should let the editor know, and just turn down the request to review.

For Kunchur, some signal processing issues are immediately evident, for example where he in the video shows some truncated sinusoidals, and presents them as signals of 440 Hz and 880 Hz, respectively, seemingly not realizing that there are infinitely many frequency components associated with finite-duration sinusoidals (see for example Communication Systems by Carlson). He also states in some paper that in general the frequency response is not capable of showing effects shown in the time domain, and demonstrates it by showing that the magnitude responses for a piece of music played forwards and backwards are the same, seemingly without realizing that the phase responses are different for the two situations, and since frequency response includes both magnitude and phase, it does indeed capture the time-reversal effect (look up Fourier Transform Pair of Time Reversal). His analogies also seem very constructed towards supporting his claims, without any real rigor to them. Finally, he seems fond of arguing ad hominem ("I have published, and you haven't, therefor I am correct, and you are wrong".), which typically makes for very muddy discussions that nobody really wants to engage in. Some actual okay points is his papers are entangled with no so correct points, and it takes a lot of time and energy to try and clear all of this up, since the problems span signal processing, acoustics, and hearing, and especially so when the author is not really receptive, and so it is easier to just give up.

When making single author papers, you have to be extremely self-critical, and not just let the official short-term peer-review determine whether or not what you are postulating actually makes sense, especially when going against well-established science. He should get a bunch of students to help him, and have some more collaboration going, such that the papers are vetted before the peer-review, instead of being questioned so much afterwards.

Thanks for your detailed answer.

 

[amirm]

Some of my PhD engineers in my signal processing team at Microsoft were on the peer review board of IEEE. I asked them once how they are able to determine if the content of a research paper is correct. The answer? That was not part of their job. They would read the paper to make sure the work is professionally done, and that it would not miss something taught to you in first or second year of college. Otherwise, it was not their responsibility, nor a function of their role to approve of disprove the findings of a paper. That was solely on the shoulders of the authors.

 

[René - Acculution.com]

There also seems to be magnitude differences in the different signals he compares, as they are seemingly not the same duration in time (although the figures are so gritty that it is difficult to really see what is going on). Everything is weird mish mash of half-truths, analogies, and conjecture. Like linking interaural time difference to the frequency range needed when evaluating cable performance. What? It should not be up to the reader to decipher all of this, it should be the author's responsibility to lay it out clearly.

 

[Somafunk]

@amirm It’s surfaced again, including your “infamous“ face palm ,your rebuttal/debunking video of Kunchar‘s paper is quoted in a puff piece titled “Scientific study claims to prove that expensive cables matter” on Headphonesty website.

 

[Jim Taylor]

@amirm It’s surfaced again, including your “infamous“ face palm ,your rebuttal/debunking video of Kunchar‘s paper is quoted in a puff piece titled “Scientific study claims to prove that expensive cables matter” on Headphonesty website.

So much for the "-honesty" in "Headphonesty".

Jim

 

[Chrispy]

So much for the "-honesty" in "Headphonesty".

Jim

Was thinking more of headphonedishonesty....

 

[EJ3]

Popcorn, anyone?

Yes please, with double whatever it is that they call butter. So that I might be able to emphasize with the "snake oil" one. (But, on second though, even double butter stuff won't get me to that state of mind. I may [probably] be CRAZY but I am not stupid).

 

[voodooless]

@amirm It’s surfaced again, including your “infamous“ face palm ,your rebuttal/debunking video of Kunchar‘s paper is quoted in a puff piece titled “Scientific study claims to prove that expensive cables matter” on Headphonesty website.

Yeah:

Of course, the ultimate test will always be our own ears.

They could have led with that and saved themselves a whole article...