Interesting Papers re temporal resolution Options

[ncdrawl]

http://www.physics.sc.edu/kunchur/Acoustics-papers.htm

http://www.physics.sc.edu/kunchur/papers/FAQs.pdf

[John_Siau]

From the summary paragraph in "Audibility of temporal smearing and time misalignment of acoustic signals" by Dr. Kunchur

These qualitative and anecdotal observations point to the possibility that human hearing may be sensitive to temporal errors, τ , that are shorter than the reciprocal of the limiting angular frequency [2πfmax]^−1 ≈ 9 μs, thus necessitating bandwidths in audio equipment that are much higher than fmax in order to preserve fidelity.

Again, the same glaring error:

The Nyquist frequency does NOT determine the temporal resolution of a PCM system. The entire premise of the paper is fundamentally flawed. The experiment proves the need for moderately controlled jitter but does not establish the need for higher sample rates.

[Axon]

From the summary paragraph in "Audibility of temporal smearing and time misalignment of acoustic signals" by Dr. Kunchur

These qualitative and anecdotal observations point to the possibility that human hearing may be sensitive to temporal errors, τ , that are shorter than the reciprocal of the limiting angular frequency [2πfmax]^−1 ≈ 9 μs, thus necessitating bandwidths in audio equipment that are much higher than fmax in order to preserve fidelity.

Again, the same glaring error:

The Nyquist frequency does NOT determine the temporal resolution of a PCM system. The entire premise of the paper is fundamentally flawed. The experiment proves the need for moderately controlled jitter but does not establish the need for higher sample rates.

That seems too harsh to me - I agree that Dr. Kunchur is making huge conceptual mistakes with his treatment of digital audio, and in a lot of other things for that matter, but the experiment itself can't be dismissed so easily. Despite all the issues I have with the paper that I mentioned earlier, isn't it at least plausible on some sort of a priori level that, if one can guarantee a distortion of fairly reasonable consistency (internal to the ear), that testing of ultrasonics on that basis may be reasonable?

[2Bdecided]

That seems too harsh to me - I agree that Dr. Kunchur is making huge conceptual mistakes with his treatment of digital audio, and in a lot of other things for that matter, but the experiment itself can't be dismissed so easily. Despite all the issues I have with the paper that I mentioned earlier, isn't it at least plausible on some sort of a priori level that, if one can guarantee a distortion of fairly reasonable consistency (internal to the ear), that testing of ultrasonics on that basis may be reasonable?

Well, that's the whole point - but this flawed experiment didn't probe this properly - and all previous proper experiments show that, apart from via bone conduction, ultrasonics don't distort to create audible frequencies in the ear.

In equipment, yes, but not in the ear.

If someone proves otherwise (quite possible), it'll be interesting.

IIRC there was someone here who did (playing ultrasonic from a separate audio system(!) and ABXing presence / absence in the presence of an audible sound), but I didn't see how the thread ended.

Cheers,
David.

[rpp3po]

I'm just coming back from vacation. Thanks for the many insightful posts, I have just learned a lot! Until now I always thought that PCM being bandwidth limited and requiring low pass filtering is just about frequencies that no human ear would care about anyway and no big deal else.

Comprehending that the plot of a properly encoded PCM bitstream of a square wave is not square, why low passing before ADC is so important, and why perfect square waves don't fit into PCM in theory took me a big leap forward.

I had already checked DVD-A prices for my favorite records online... But until I see Kunchur refuting some of this thread's objections I'll stay as happy with Redbook as I always have been.

This post has been edited by rpp3po: Aug 2 2009, 19:09

[Arnold B. Kruege...]

But until I see Kunchur refuting some of this thread's objections I'll stay as happy with Redbook as I always have been.

As you seem to be saying, there's a lot of interesting twists along the way, but getting back to basics is very often a good thing.

Setting up a proper listening test that shows that high sample rates do make a difference with music is simpler and less costly than ever.

There is now a ton of high sample rate audio kicking around for free or not much money. Actually setting up the experiment can be accomplished with not only reasonably-priced buyware, but even with freeware.

There seems to be only one minor thing lacking - a pair of ears that produce results that are positive for high sample rates.

Whenever we see a paper like Kunchur's, we need to get back to basics. The basics are that just about anybody who wants to can set up a reliable listening test involving readily-available musical program material that has the potential to produce a positive outcome. Nobody seems to be able to do it. Instead, all we get are these abstract tests like Kunchur's, involving some most definately non-musical waveforms with questionable relevance and inconclusive results.