Anderton
The plot thickens...
 
Actually, both Bitflpper and I might be wrong about 96 making a difference only with signals inside the computer. No less an authority than James A. Moorer wrote a paper that proposed, among other things, that hearing involves not just frequency and amplitude, but time and how it relates to localization when listening with both ears. He claims that most people can distinguish a time delay of 15 microseconds or more when a pulse is put into each ear, and that some people can differentiate delays as low as 3 to 5 microseconds. Given that a sample at 48kHz is about 21 microseconds and 10.5 microseconds at 96kHz, that means the minimum time delay most people can differentiate is actually less than one sample at 48kHz, but more than one sample at 96kHz. 

Sorry, but I must call BS on this.  According to the sound/time caculator HERE, 15 microseconds is the equivalent of moving you head half a cm (5 mm).  5 microseconds is more like 2 mm.  There would be more than a 2mm variation between the driver and you eardrums each time you put your headphones on.  It is highly unlikely that at any time, the drivers of your headphones are at an exact distance from each eardrum, I would say the variation would exceed 2 mm every time you put them on.
 
Now, take that argument to speakers and you are talking about one drop of water in the pacific ocean.  Absolute BS.  Yes, I know this guy's credentials, but come on...

This has nothing to do with frequency. Moorer's paper was about binaural hearing and the perception of delays between events, not listening to continuous frequencies. I would guess this is a refinement of the precedence effect "the first wavefront law"). He maintains people with average acuity can recognize a time differential between impulses hitting each ear of as little as 15 microseconds, and some could discriminate down to 5-8 microseconds.

Interesting hypothesis.
 
It's true that our spatial perception depends on very small phase shifts between left and right ears. However, the time difference for any given angle of incidence is constant and based on the speed of sound and how long it takes sound to traverse the width of your head.
 
That's going to be hundreds of microseconds, not tens of microseconds. Unless you're a rodent, anyway.
 
Now, if you're talking about discrete events that occur 15 microseconds apart, you've got to ask yourself what that means in a musical context. When you strum a guitar, what is the time difference between each string being plucked? 20 microseconds, perhaps? I can't think of any musical event that happens faster than that.
 
You also have to question whether or not conventional electromagnetic speakers can even reproduce events that close together. Certainly not for low frequencies. But even the best tweeters still have mass that limits to how quickly they can respond and reset.

Silicon Audio
According to the sound/time caculator HERE, 15 microseconds is the equivalent of moving you head half a cm (5 mm).  5 microseconds is more like 2 mm.  There would be more than a 2mm variation between the driver and you eardrums each time you put your headphones on.
 

Well, he's not alone by any means, and experiments done with ferrets, cats, owls, and other predatory animals seem to indicate binaural localization discrimination on the same level as humans. 
 
There's a really interesting paper, "Behavioral Sensitivity to Broadband Binaural Localization Cues in the Ferret." It was written up by the Journal of the Association for Research in Otolaryngology. Here's an excerpt:

Binaural cue sensitivity

In some cases, ferrets exhibited ITD thresholds of <20 μs, with the mean threshold across animals and sessions equal to 23 μs for 200-ms broadband stimuli. Despite some differences in methodology between studies, these data are broadly comparable with ITD discrimination thresholds in humans, which are typically 10–20 μs (Zwislocki and Feldman 1956; Klumpp and Eady 1957; Yost 1974), as well as those reported for macaques (Scott et al. 2007), cats (Wakeford and Robinson 1974), and owls (Moiseff and Konishi 1981). The ITD thresholds obtained from ferrets are slightly better than those found in rabbits (Ebert et al. 2008), which is consistent with the notion that predatory species may have more developed sound localization abilities. Ferrets are also very sensitive to changes in ILDs, with some animals having thresholds of <1 dB, while the mean value for 200 ms of flat-envelope stimuli was 1.3 dB. Again, these thresholds are broadly comparable with those observed in humans, which typically vary from 0.5 to 1 dB over a wide range of frequencies (Mills 1960), as well as those obtained from macaque monkeys (Scott et al. 2007) and cats (Wakeford and Robinson 1974).
 
It's one thing to sit here on a forum and offer conclusions based on what seems logical, but this kind of research is well-documented, repeatable, written by people who are authorities in their field, and have initial research precedents dating back over half a century. If you check out the paper, the authors give complete details on the methodology used, and there are enough references and links that if you follow them all, you won't be back to this forum for weeks.
 
I haven't verified the results myself, so I can't say from personal experience whether I accept their findings or not. But I would find it very hard to dismiss arbitrarily the amount of hours invested in these studies by a vast number of scientists who are interested solely in pure research.
 
 

bitflipper
Unless you're a rodent, anyway.

 
Are you psychic?!? Check out the previous post, which I was writing while you were writing yours...
 

Now, if you're talking about discrete events that occur 15 microseconds apart, you've got to ask yourself what that means in a musical context. When you strum a guitar, what is the time difference between each string being plucked? 20 microseconds, perhaps? I can't think of any musical event that happens faster than that.

 
"Events" can be the crest of a waveform hitting your ear. Flanging can cause separate events that are separated by 0 seconds. Don't know what the resolution is for electronic flanging, but an airplane going overhead while you're standing in front of a wall goes through zero and goes through sub-microsecond variations on the way there.
 

You also have to question whether or not conventional electromagnetic speakers can even reproduce events that close together. Certainly not for low frequencies. But even the best tweeters still have mass that limits to how quickly they can respond and reset.

 
True, and a very good point. But we don't just hear point source material. We hear this amazing number of reflections, cancellations, and additive peaks because we have to listen in an environment. That's what provides the spatial and localization cues. Think about bats and how they navigate, but if you've known any blind people, for many their ability to localize sounds is off the hook.
 
Again, I'm not saying anyone's right or wrong. I'm just saying that it's important to keep an open mind and not dismiss anything just because a preconceived notion of what's logically correct doesn't agree with tens of thousands of man-hours of research. The conclusions the researchers derive could be wrong, and extrapolation to musical reproduction could be wrong. But it could also be right. I don't think anyone here on the forum has sufficient knowledge to confirm or dispute these claims at the same level of depth with which they're made.
 
I'm here to learn, and being sure of one's knowledge impedes that process. I assume that everything I know is not right or wrong, but potentially right or potentially wrong. 
 

drewfx1
And you know that Fourier says that any complex waveform is just a combination of sine waves at various frequencies, amplitudes and phases.

I know that, but I also know that applies only to a situation involving a single audio stream. Anyone with two ears hears two audio streams. There is no way (other than offline encoding processes) for a single audio stream to represent two independent audio streams. Even playing back a mono sound source over stereo speakers generates two independent audio streams due to room acoustics. I don't see how it would even be possible to obtain localization information from a single audio stream. 

bitflipper
It's true that our spatial perception depends on very small phase shifts between left and right ears. However, the time difference for any given angle of incidence is constant and based on the speed of sound and how long it takes sound to traverse the width of your head.
 
That's going to be hundreds of microseconds, not tens of microseconds. Unless you're a rodent, anyway.
 

If the sound source is slightly to one side and some distance away it can have a very small ITD between your ears.
 
Or am I mis-Pythagorizing it? 

.

Anderton

Binaural cue sensitivity

In some cases, ferrets exhibited ITD thresholds of <20 μs, with the mean threshold across animals and sessions equal to 23 μs for 200-ms broadband stimuli. Despite some differences in methodology between studies, these data are broadly comparable with ITD discrimination thresholds in humans, which are typically 10–20 μs (Zwislocki and Feldman 1956; Klumpp and Eady 1957; Yost 1974), as well as those reported for macaques (Scott et al. 2007), cats (Wakeford and Robinson 1974), and owls (Moiseff and Konishi 1981). The ITD thresholds obtained from ferrets are slightly better than those found in rabbits (Ebert et al. 2008)...

Cakewalk obviously needs more ferrets in its Beta testing group

I would think at timescales like this simply moving your head into a different angle would have a more significant effect (and thus negate any difference between the output of the two speakers). I haven't read Moorer's article yet but generally speaking this seems a pretty wild conclusion to draw from a carefully done experiment in very controlled conditions. That's not really how science works (although the media would like it to).

64 bit precision mice? hmmmmm....