Comment Re:Hardware sampling rates (Score 4, Interesting) 121
I was under the impression that while humans mostly cannot hear ultrasonic sounds, the existence of them can be perceived as a kind of "texture" to other sounds that we can hear. Removing these frequencies all together from all sounds sources can make stuff sounds more artificial.
The timbre of any sound is due to harmonics -- frequencies higher than the fundamental. MP3 and other lossy compression schemes do indeed remove some of the quieter harmonics. However, if the harmonics are outside the hearing range, well, then you can't hear them.
However, there may be nonlinear effects which convert some of the ultrasound to lower frequencies. Also, when a frequency exceeds the Nyquist limit (half the sampling rate), it is aliased to a frequency within the sampling range. (Hence "anti-aliasing", which is simply filtering out too high frequencies to prevent this effect.)