wrote:

I didn't know about the differences in high/low pitch localization like
you described. I knew bass was more omni-directional, but the stuff
you described is definitely a new one for me.

Bass _production_ and _reproduction_ is more omnidirectional, only because
the wavelength is longer. You can make a bass horn that is just as
directional as a PA horn at 1 KC, it just has to be a few hundred times
larger. The bass directionality issue is only due to size of the sources
and microphones.

But imaging is a different matter altogether. Now, remember that most
recordings today are just panpotted stereo and have only amplitude
differences between channels, no phase differences. This isn't real
stereo at all, and the low end imaging suffers very badly.

Some systems out there, like Q-Sound have tried to add real phase
differences between channels without stereo miking, but they tended to
get overused and got a bad name.

Is there a ballpark frequency range above where it becomes mostly
amplitude?

I think by 1 KHz or so, interchannel phase differences aren't much of
an issue any more. At 1 KHz, your head is about half a wavelength wide
and that's about the point at which the differences start to become
useless. The actual point, of course, varies with your exact head size
and shape.

But down at 50 Hz, there is _no_ perceived amplitude difference at all
because the distance between your ears is so much shorter than a wavelength.

There is a nice discussion of some of this stuff on
http://www-engr.sjsu.edu/~duda/Duda.Research.html somewhere, I think.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."