"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:1qu09392icr130gp0c25lcnftjm6ifg96t@4ax.com...
>>An audible beat tone is produced by the constructive and destructive
>>interference between two sound waves in air. Look at a pictorial
>>representation (in the time domain) of the sum of sine waves,of similar
>>amplitudes, one at, say, 1000 Hz and the other at 1005, and you'll
>>see it.
>>
>>Bob M.
>
> I beg to differ. There's no mixing happening in the air.

Nor did I say there was. The phenomenon of interference
between two compression waves in a given medium is not
an example of "mixing."

> of air is very linear (Boyles Law or PV=constant). If there were
> mixing, you would be able to hear the beat note when one generates two
> ultrasonic tones. I belch 25KHz and 26KHz from two transducers, by
> our logic, air mixing would create a 1KHz beat note. It doesn't and
> you hear nothing.

That was exactly my point. Please read ALL responses I've
made re this topic.

> What seems to be the problem here is the model of the human ear is not
> what one would assume. It is NOT a broadband detector. The cochlea
> cilia (hairs) resonate at individual frequencies. Each one resonantes
> at only one frequency (and possibly some sub-harmonics). Therefore,
> the human ear model is a collection of narrow band filters and
> detectors. Unless the two frequencies involved both cause a single
> cilia to simultaneously vibrate at both frequencies, there isn't going
> to be any mixing. Each detector can be individually quite non-linear,
> but as long as it vibrates at only one frequency, there isn't going to
> be any mixing.

This is also a point I noted earlier in this thread.

Bob M.