On Tue, 29 Oct 2002, Tim Walters wrote:
> If the human ear can't hear anything above 20kHz, then it makes no
> difference at all if a 15kHz square wave looks better on the scope sampled
> at 96kHz. (It'll only look a little better, anyway.)
And there's the rub. Most people CAN distinguish between high frequency
sines and triangles, even though the harmonics of the triangle are above
the range of their hearing. Ultrasonic components have an effect on
perception, even if they can't be heard. Further proof of this is the
"audio spotlight" that delivers audio using ultrasonics (see
holosonics.com).
The question is, how high do you need to go to accurately reproduce a
performance? Horns are the acoustic instruments that produce the most
ultrasonics, and they don't do much past 50kHz. A VCO can go as high the
air's ability to carry the vibration, but there's a point where it just
doesn't matter to humans.
JDM
PS we're beginning to sound like ANALogue HeAVEN. :P