"íçëéìèî" wrote in message
...
Hello,

In addition to the Fletcher-Munson equal loudness curves describing our
psycho-acoustic response, are there any curves to describe distortion in
the
ears?

ie. Does each set of ears/brain have a second and third order
intermodulation intercept point?

ie. Can you be bombarded with large SPLs of pure sinewaves at 20kHz and
24kHz and perceive 4kHz (F2-F1) and 16kHz (2F1-F2).

I'm sure it's vastly more complicated than this....?



I seem to remember reading about a Korean(?) company experimenting with a
public address system that generated a carrier around 20KHz plus an audio
signal shifted up by 20KHz, the assumption being that the non-linearity of
the ear would make it audible. The transducers were placed in a matrix
several feet above head height, and because of beaming at these frequencies
the sound(!) would appear generally from above. But the last I heard was
that they were experimenting with a membrane above the listener to create
additional non-linearity.

Graham Holloway