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48 KHz vs 96 KHz - Page 2

post #31 of 50
Quote:
Originally Posted by sk20 View Post

I'm actually kind of shocked that the consumer-electronics industry didn't embrace the original study (with or without corroboration) and use it as a way to sell a whole new line of Ultrasonic Capable[tm] equipment and media ("I'll have to buy the 'White Album' again"). They could have made a fortune.

I thought that was the idea of the original study (funded by an electronics company selling, among other things, speakers with super-tweeters going above 20kHz). Perhaps that was the reason nobody was interested in replicating the results.
post #32 of 50
Quote:
Originally Posted by rock_bottom View Post

I thought that was the idea of the original study (funded by an electronics company selling, among other things, speakers with super-tweeters going above 20kHz). Perhaps that was the reason nobody was interested in replicating the results.

If that's the case, that would be sad, because that's no way to conduct science.

Just because a study is funded by Company A that desperately wishes to have Result B come out of the study doesn't mean they'll get Result B. And if they get Result B, that doesn't mean the study is wrong.

The trouble arises when Company A spikes a study that disproves (or fails to prove) Result B. In that case, the funding agent is interfering with science. I have no evidence that the company in question (I assume it's Murata) spiked any studies.

By the way, despite that discussion over on Stereophile being a snakepit, they do refer to another scientist who has found evidence that frequencies above 20 kHz matter:

http://www.physics.sc.edu/kunchur/Acoustics-papers.htm
post #33 of 50
Yes, that Stereophile forum discussion was indeed a snake pit. There's a more thorough and civilized discussion of the Kunchur papers here.
post #34 of 50
Quote:


I would expect in that case are some links to the other studies that shot down the original study, or at least some abstracts. I don't see such links.

Now you do. Essentially, this study replicated the earlier one, then showed that what the earlier researchers ascribed to ultrasonic content might actually be attributable to IM distortion below 20kHz.

Quote:


I'm actually kind of shocked that the consumer-electronics industry didn't embrace the original study (with or without corroboration) and use it as a way to sell a whole new line of Ultrasonic Capable[tm] equipment and media ("I'll have to buy the 'White Album' again"). They could have made a fortune.

A few people over the years have tried to hype that study in defense of higher sampling rates (SACD, DVD-A). That the manufacturers of those technologies did not do so suggests that the study wasn't as important to them as you might imagine. It takes more than one study to make a scientific case, especially when the researchers can't explain their results.
post #35 of 50
Quote:
Originally Posted by sk20 View Post

The range of human hearing is higher than commonly reported, at least in terms of seeing a change in the brains of people hearing ultrasonics:

http://www.ocf.berkeley.edu/~ashon/a...ltrasonics.htm

This link appears to be broken.

The correct link appears to be:

http://www.ocf.berkeley.edu/~ashon/a...ltrasonics.htm

It appears to be a homework paper from the year 2000. It contains a number of errors of fact and logic.

It references the Ooashi paper, about which there is more information about it here:

http://en.wikipedia.org/wiki/Hypersonic_effect

Note that this is a widely-disputed paper and thus hardly reliable evidence, at least until the disputes are resolved.
post #36 of 50
Quote:
Originally Posted by rock_bottom View Post

Yes, that Stereophile forum discussion was indeed a snake pit. There's a more thorough and civilized discussion of the Kunchur papers here.

Speaking of snake pits, a thead with similar topic and technical content to this one has gone missing in the past few days...
post #37 of 50
Quote:
Originally Posted by mcnarus View Post

Now you do. Essentially, this study replicated the earlier one, then showed that what the earlier researchers ascribed to ultrasonic content might actually be attributable to IM distortion below 20kHz.

Hm. The study you point to says the difference is due to using a single speaker, yet:

http://www.sciencedirect.com/science...222c2a065c25aa

says the ultrasonic effect disappears with headphones but not with a single speaker. Yet headphones also have a single speaker (per ear).

Or does the study you point to claim the problem is due to intermodulation distortion between the two speakers (which wouldn't happen with headphones)?

This would seem to be something meriting further study.
post #38 of 50
Quote:
Originally Posted by sk20 View Post

Hm. The study you point to says the difference is due to using a single speaker, yet:

http://www.sciencedirect.com/science...222c2a065c25aa

says the ultrasonic effect disappears with headphones but not with a single speaker. Yet headphones also have a single speaker (per ear).

There are massive operational differences between headphones and speakers.


Quote:


Or does the study you point to claim the problem is due to intermodulation distortion between the two speakers (which wouldn't happen with headphones)?

Here's the conclusions from the end of the paper:

Quote:


There has been a controversy about audibility of ultrasounds. In
1981, Muraoka et al.[8] used musical sounds and reported that only a
few out of 176 subjects distinguished the sounds with and without
components above 20 kHz. Several recent studies, on the other hand,
revealed that the ultrasonic components would significantly affect the
sound impression of the normal listeners. In the present study,
audibility of the components above 22 kHz was investigated under
monaural and stereophonic listening conditions.

The subjects could discriminate the stimuli with and without
ultrasounds only when all components were mixed and presented
through the same loudspeaker. When as many as 6 loudspeakers
were used in order to prevent intermodulation, no one could
discriminate the stimuli. No significant difference was found
between monaural and stereophonic conditions. It was indicated from
the results that the non-linear interaction of ultrasounds in the air or
in the auditory system was, if any, not so much as that in the average
loudspeakers as far as the level of the signal did not exceed 80 dB
SPL.

It was shown that under conditions in which experimental artifacts
had been adequately eliminated, ultrasounds would be extremely
difficult to be perceived. They may have little influence on the sound
image and its localization. Different sound impression perceived by
the subjects in the single-loudspeaker condition(Exp. 1) and in the
dual-loudspeaker condition(Exp. 2) was because of different
acoustical characteristics in the audible area due to experimental
artifacts.

In the present study, only a synthesized complex tone was used and
no data have been available for musical sounds and natural sounds

This would seem to be something meriting further study.[/quote]

I cited greisinger's further study, above:

http://www.davidgriesinger.com/intermod.ppt

That's a direct link to the study as presented. Have you studied it?

Quote:


The loudspeakers tested have intermodulation distortion lower than the threshold of detection for complex tones.

The author found audible IM elsewhere in the reproduction chain.
post #39 of 50
Quote:
Originally Posted by arnyk View Post

Speaking of snake pits, a thead with similar topic and technical content to this one has gone missing in the past few days...

Now that you mention it, I see what you're saying.
post #40 of 50
Quote:
Originally Posted by RWetmore View Post

Huh??? You most certainly do not need to separately mic the whole orchestra to capture components above 22khz.

First off, what does "above 22 KHz" mean. Does it mean capturing from 22 KHz to 23 KHz? No, it can't be just from 22 to 23 KHz because that would be like 1/20 of an octave which is perceptually insignificant even at 5 KHz.

How about from 22 KHz to 44 KHz with negligable losses? That's a full octave and would be signficiant other than the (disputed) ultrasonic means can't hear, thing. So for the purpose of discussion, we want reasaonbly flat response up to 44 KHz, right?

But we're back at the point where the losses at 44 KHz over concert hall distances are pretty impressive. I mean like 10s and 10s of dB being lost. You'd be very unhappy if this was going on at say 10 KHz, and isn't the idea being proposed that losses at 20KHz are something like as signfigicant as losses at 10 KHz? Maybe less, but still like 1/4 or 1/3 as important?

First off, the dimensions of a seated full orchestra may surprise you. I previously mentioned > 100:1 loss of HF information over a 20 meter or 60 foot distance.

So how large is the onstage seating area in a good sized concert hall? The answer may surprise you - 60 feet wide (proscineum opening) and 50 feet deep (proscineum to back of shell) with maybe a 10-15 foot distance from the proscinium to the lip of the stage and another 6-10 feet to the first row of seats. BTW, did you notice that the percussion instruments tend to be parked towards the back?

Oh so you don't want to sit in the front row? Well add maybe 3 feet or more for every row back.

Now check out how people minimally mic orchestras. The first row of mics are probably in the area between the proscinium and the lip of the stage. There are probably some ambience mics suspended above the seating area, maybe 1/3 or 1/2 of the way back. All the mics are at least 10-15' above the floor.

So, that 60 foot number is pretty much ballpark for minimal micing of the orchestra. And, its more like 100 feet to a good seat in the house.

Again, presuming that ultrasonic overtones are audible, if you close mic with a good wideband mic (very rare and expensive BTW) then the mic is going to get an abundance, as in 10s of dB more ultrasonics than a person would get when seated in a good seat in the house. If the recording is a DACD or high sample rate DVD-A, then the medium is going to reproduce this gross excess of ultrasonics quite well. Finally, you've seated yourself 3-6 feet from your speakers and exactly on-axis so again the losses for ultrasonics are going to be minimal.

But didn't we just figure out that our close-miced recording is going to have 10s of dBs more ultrasonics than a really good seat in the house?

Why isn't it that people with really good speakers aren't running out of their listening rooms screaming having been deafened by this probable gross excess of ultrasonics on their close-miced SACDs and DVD-As?

The reason is quite simple. The ultrasonics are truely inaudible and we can't hear whether there is 10 times too much, or 10 times too little or that they are just right.

Hey, we're still having way too much trouble getting things right *below* 20 KHz. Let's not make this Hi Fi thing even more complex than it already is!
post #41 of 50
Good points.

Mike
post #42 of 50
Quote:
Originally Posted by mcnarus View Post

Essentially, this study replicated the earlier one, then showed that what the earlier researchers ascribed to ultrasonic content might actually be attributable to IM distortion below 20kHz.

I'm no Kal Rubinson, but that sure make sense to me. If the upper frequency limit of hearing is mechanical and physical, I can't see how higher frequencies could get into the brain to be "perceived" in the first place. However, I am very well aware that IM products are created inside the ears, often at loud levels, so that seems a far more likely explanation.

In more practical terms, even if some people could perceive > 20 KHz in some situations, who cares? I can enjoy a good piece of music even if it's band-limited at 15 KHz, or 10 KHz. How is it sensible to double the needed bandwidth and storage for a curiosity that has no real affect on enjoyment, and affects only a tiny proportion of the public?

--Ethan
post #43 of 50
Just some observations.

Part of the issue in the research (and in lay response) is the inconsistent use of the terms "audible" and "perceivable". The fact that vibrations in air may, or may not, be perceived by a human should not imply they are audible nor qualify as sound. Once the "can be perceived" issue is settled, then the debate can begin with respect to the affect of that perception. (Along with the study with respect to exactly what the perception mechanisms may be.)

The two other rather fundamental issues (getting to the snake pit scenario) is that often those reading the research don't have the underlying knowledge to correctly judge the viability of either the thesis, the procedural research, nor the conclusion. Secondly, lay persons can have a tendency to focus only on those citations, or original work, which support their own views whilst failing to review, and research, the work resulting in a contrary or opposite conclusion.

While the topic warrants discussion and could prove to be an excellent topic for a Ph.D. candidate, the name calling and personal attacks belong in the back alley between high school drop outs ... not in a meaningful academic discussion. The truly knowledgeable in these observed threads have behaved as real gentlemen and exhibited a patience well beyond my limits.

Poor citations, citing non-relevant work, and failing to take a 360 degree approach to reviewing the topical research is, sadly, a failing I've found even with Juniors and Seniors in a Physics major.
post #44 of 50
Quote:
Originally Posted by arnyk View Post

First off, what does "above 22 KHz" mean. Does it mean capturing from 22 KHz to 23 KHz? No, it can't be just from 22 to 23 KHz because that would be like 1/20 of an octave which is perceptually insignificant even at 5 KHz.

How about from 22 KHz to 44 KHz with negligable losses? That's a full octave and would be signficiant other than the (disputed) ultrasonic means can't hear, thing. So for the purpose of discussion, we want reasaonbly flat response up to 44 KHz, right?

But we're back at the point where the losses at 44 KHz over concert hall distances are pretty impressive. I mean like 10s and 10s of dB being lost. You'd be very unhappy if this was going on at say 10 KHz, and isn't the idea being proposed that losses at 20KHz are something like as signfigicant as losses at 10 KHz? Maybe less, but still like 1/4 or 1/3 as important?

First off, the dimensions of a seated full orchestra may surprise you. I previously mentioned > 100:1 loss of HF information over a 20 meter or 60 foot distance.

So how large is the onstage seating area in a good sized concert hall? The answer may surprise you - 60 feet wide (proscineum opening) and 50 feet deep (proscineum to back of shell) with maybe a 10-15 foot distance from the proscinium to the lip of the stage and another 6-10 feet to the first row of seats. BTW, did you notice that the percussion instruments tend to be parked towards the back?

Oh so you don't want to sit in the front row? Well add maybe 3 feet or more for every row back.

Now check out how people minimally mic orchestras. The first row of mics are probably in the area between the proscinium and the lip of the stage. There are probably some ambience mics suspended above the seating area, maybe 1/3 or 1/2 of the way back. All the mics are at least 10-15' above the floor.

So, that 60 foot number is pretty much ballpark for minimal micing of the orchestra. And, its more like 100 feet to a good seat in the house.

Again, presuming that ultrasonic overtones are audible, if you close mic with a good wideband mic (very rare and expensive BTW) then the mic is going to get an abundance, as in 10s of dB more ultrasonics than a person would get when seated in a good seat in the house. If the recording is a DACD or high sample rate DVD-A, then the medium is going to reproduce this gross excess of ultrasonics quite well. Finally, you've seated yourself 3-6 feet from your speakers and exactly on-axis so again the losses for ultrasonics are going to be minimal.

But didn't we just figure out that our close-miced recording is going to have 10s of dBs more ultrasonics than a really good seat in the house?

Why isn't it that people with really good speakers aren't running out of their listening rooms screaming having been deafened by this probable gross excess of ultrasonics on their close-miced SACDs and DVD-As?

The reason is quite simple. The ultrasonics are truely inaudible and we can't hear whether there is 10 times too much, or 10 times too little or that they are just right.

Hey, we're still having way too much trouble getting things right *below* 20 KHz. Let's not make this Hi Fi thing even more complex than it already is!

Arny, you are missing the point entirely. First of all the perspective of a particular recording may not be intended to emulate what a seat in a concert hall would sound like. The intended perspective might be one closer to the conductor or the musicians themselves, for example - depending on the music, the choice of the artists or engineer, Etc.. But that's really beside the point. I don't doubt that in many instances little or no ultrasonics make it to the microphones. However, in some instances they most definitely would. Also there are ultrasonics that routinely come off analog tape and vinyl records.

Now your own experimentation and the experimentation of others has turned up negative on anyone being able to hear or perceive those ultrasonics. I understand; however, given my own listening experiences and the many reported experiences of others, I am not yet convinced that ultrasonics are completely inaudible to everyone in existence, with any and all recorded content, in every environment. You are - that's wonderful. I'm happy for you.

No, hi-rez is not a means to end. I think of it as insurance. Insurance that the full sound is recorded and then passed through our systems during playback. My philosophy is record the full sound and send out the full sound during playback. This way we can be certain that any sonic shortcoming must lie somewhere outside the recording format itself. It would not take more than 176.4khz/20bit PCM to achieve this - as this takes us a little beyond what even the best equipment can actually do.

IMO, you've taken this beyond the realm of science into some kind of pseudo-scientific religious belief system. Do I think it is likely that I can hear or perceive components at 50khz? No, I think it is highly unlikely; however the human body is not immune to ultrasonic frequencies, and the process of listening to music is a combination of absorbing sound through the body and the ear.

In short, I want the "full sound." To a purist who wants to ensure he's getting the best sound possible, trying to figure out where the thresholds of audibility or perceivability lie isn't a game worth playing - especially since most the industry records in at least 96khz/24bit.
post #45 of 50
My experience in taking direct to digital at 50kHz sampling and "moving" that to vinyl, would strongly suggest none of the ultrasonics coming from the vinyl playback system were a part of the digital master. (Regardless of mic technique used.)

I would also suggest there is a population fretting ( snicker) over the possibility either a recording or their playback system is not delivering the full original musical experience. Having spent time on both sides of the microphone, I agree with them ... they are missing something. My own experience is that part which is missing (forever) has absolutely nothing to do with the presence, or lack of, ultrasonic content.
post #46 of 50
Quote:
Originally Posted by Dennis Erskine View Post

My experience in taking direct to digital at 50kHz sampling and "moving" that to vinyl, would strongly suggest none of the ultrasonics coming from the vinyl playback system were a part of the digital master. (Regardless of mic technique used.)

I know.

Quote:
Originally Posted by Dennis Erskine View Post

I would also suggest there is a population fretting ( snicker) over the possibility either a recording or their playback system is not delivering the full original musical experience. Having spent time on both sides of the microphone, I agree with them ... they are missing something. My own experience is that part which is missing (forever) has absolutely nothing to do with the presence, or lack of, ultrasonic content.

We know.
post #47 of 50
Quote:
Originally Posted by RWetmore View Post

Arny, you are missing the point entirely.

The above is not an unusual response after I score a direct hit on some sacred cow someplace. ;-)

Quote:


First of all the perspective of a particular recording may not be intended to emulate what a seat in a concert hall would sound like.

The obvious pedantic point is that you are denying your own claim, RW. You didn't say that I may be missing the point some of the time or a little bit of the time or even most of the time, you said that I am "missing the point entirely". *Entirely* means that I am *always* missing the point. I never, nine, nichts, nada hit the point or come anyplace near it. That is what you said, RW.

RW, a claim that I am "missing the point entirely" in this context requires you to prove that there is nobody, no place, no time who wants a recording that emulates what a seat in a concert hall would sound like or even comes close.

That is obviously completely rediculous not to mention being a negative claim that is always difficult or impossible to prove.

So right up front RW you must prove that there is nobody, no place, no time who wants a recording that emulates what a seat in a concert hall would ever sound like or even vaguely approximate it, or you are simply engaging in hyperbole.

The ball is in your court RW, either prove that there is nobody, no place, no time who ever wants a recording that emulates what a seat in a concert hall would sound like or even vaguely approximate it, or humbly admit you are simply engaging in hyperbole and your claim deserves no further serious consideration from anybody.

I await your answer on this critical issue, RW!
post #48 of 50
Quote:
Originally Posted by arnyk View Post

The above is not an unusual response after I score a direct hit on some sacred cow someplace. ;-)

Are you sure about that?

Quote:
Originally Posted by arnyk View Post

The obvious pedantic point is that you are denying your own claim, RW. You didn't say that I may be missing the point some of the time or a little bit of the time or even most of the time, you said that I am "missing the point entirely". *Entirely* means that I am *always* missing the point. I never, nine, nichts, nada hit the point or come anyplace near it. That is what you said, RW.

RW, a claim that I am "missing the point entirely" in this context requires you to prove that there is nobody, no place, no time who wants a recording that emulates what a seat in a concert hall would sound like or even comes close.

That is obviously completely rediculous not to mention being a negative claim that is always difficult or impossible to prove.

So right up front RW you must prove that there is nobody, no place, no time who wants a recording that emulates what a seat in a concert hall would ever sound like or even vaguely approximate it, or you are simply engaging in hyperbole.

The ball is in your court RW, either prove that there is nobody, no place, no time who ever wants a recording that emulates what a seat in a concert hall would sound like or even vaguely approximate it, or humbly admit you are simply engaging in hyperbole and your claim deserves no further serious consideration from anybody.

I await your answer on this critical issue, RW!

Do you?
post #49 of 50
If the goal of recording and playback technology is to reproduce, as closely as possible, the experience of live music, then how about an experiment that would be pretty easy to do, and would at least establish how well current technology does at achieving that goal?

Put both a band and a high-end audio system behind a screen. Have the band play. Then play the high-end audio system. Then have the band play again. Then high-end audio. Now start mixing them up randomly. Sometimes the band. Sometimes a recording of the band. Have an audience listen to this and indicate on a notepad when they think they're listening to live music vs. listening to a recording.

If the audience can tell when they're listening to a recording, then there is a problem *somewhere* in the technology. At that point, the burden shifts away from proving or disproving that ultrasonics are the culprit. Instead, the burden is now on the technologists figuring out what the problem is.

Anyone care to predict what the result of this simple test would be? Or do you already know the audience could tell the difference?
post #50 of 50
Quote:
Originally Posted by sk20 View Post

If the goal of recording and playback technology is to reproduce, as closely as possible, the experience of live music, then how about an experiment that would be pretty easy to do, and would at least establish how well current technology does at achieving that goal?

Put both a band and a high-end audio system behind a screen. Have the band play. Then play the high-end audio system. Then have the band play again. Then high-end audio. Now start mixing them up randomly. Sometimes the band. Sometimes a recording of the band. Have an audience listen to this and indicate on a notepad when they think they're listening to live music vs. listening to a recording.

If the audience can tell when they're listening to a recording, then there is a problem *somewhere* in the technology. At that point, the burden shifts away from proving or disproving that ultrasonics are the culprit. Instead, the burden is now on the technologists figuring out what the problem is.

Anyone care to predict what the result of this simple test would be? Or do you already know the audience could tell the difference?

This is the classic "Live versus Recorded" demonstration that has been repeated over and over again across the history of the recording art. Use my search string and you'll come up with almost 40,000 hits, the first of which is a PowerPoint presentation that is as good as any:

http://faculty.ed.uiuc.edu/burbules/...ials/music.ppt

By the standards of high resolution listening tests that we've been doing with audio equipment, the proposed test is pretty easy to ace even if the live and recorded music were quite identical by audiophile standards.

I seriously doubt if the musicans would be able to stay within 10 milliseconds and 0.1 dB of the timing and level of the recording, or vice-versa. Failing that, reliable detection of the difference by the sorts of trained listeners we use for ABX testing is pretty well guaranteed.

Besides there's always the question of which high end equipment, or whether the equipment has to be high end at all.

You seem to have been drinking heavily of the high end audio Kool Aid that says that only high end audio gear can even come close to realism or that high end gear is required to come closest.

If we could come as close if not closer with good mid-fi or professional-grade equipment, and I think we could, then you'd probably not be a very happy camper.

If you were willing to do your demo with SETs, LPs, and "Fast Subwoofers", I think some well chosen gear from the mid fi or professional side of audio would do a number on you.
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