In article <1qu09392icr130gp0c25lcnftjm6ifg96t@4ax.com>,
Jeff Liebermann <jeffl@cruzio.com> wrote:

> "Bob Myers" <nospamplease@address.invalid> hath wroth:
>
> >"Ron Baker, Pluralitas!" <this@aint.me> wrote in message
> >news:468fe7df$0$16560$4c368faf@roadrunner.com.. .
>
> >> No nonlinearity is necessary in order to hear
> >> a beat?
> >> Where does the beat come from?
>
> >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. compression
> of air is very linear (Boyles Law or PV=constant).

In general, that's true, but take a look at what happens in the throats
of high-powered horn loudspeakers. You can find info in e.g. "Acoustics"
by Beranek.

Isaac