48 KHz vs 96 KHz - Page 2

Originally Posted by sk20

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.

Originally Posted by rock_bottom

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.

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.

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.

Originally Posted by sk20

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

Originally Posted by rock_bottom

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

Originally Posted by mcnarus

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.

Originally Posted by sk20

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)?

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

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

Originally Posted by arnyk

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

Originally Posted by RWetmore

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

Originally Posted by mcnarus

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.

Originally Posted by arnyk

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!

Originally Posted by Dennis Erskine

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.)

Originally Posted by Dennis Erskine

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.

Originally Posted by RWetmore

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.

Originally Posted by arnyk

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

Originally Posted by arnyk

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!

Originally Posted by sk20

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?