Pat the Turd wrote:


But let's consider the Doppler distortion.

If we have a bass-midrange driver, and we have a nice fat 100 Hz tone
applied, and we have a lower amplitude 1 kHz tone, then we must be getting
Doppler distortion, ie, the perceived frequency
of the 1 kHz varies higher and lower depending on the
bass note making the cone travel to or away from us, respectively.

If we picked up the signal with a microphone close to the cone,
and used this signal as a feedback signal ....


** Motional feedback has been done to linearise bass drivers using
accelerometers attached to the cone - loop stability is hairy but it can
be made stable over the lowest few octaves.

This does nothing to reduce Doppler effects in the driver - nothing
can.



Meanwhile, someone playing a cello low note has the harmonics coming from
the
sound board which is wobbling at lower F, so Doppler effects are inherent
in
musical instruments.

** Silly straw man argument - there is of course NO natural Dopper effect
between *different* instruments.

Also, whatever Doppler effects exists with a cello - the reproduction
system should add not one jot more.

Electrostatic speakers have way less Doppler, IM, THD and thermal
compression than cone speakers - as a result they are accused of sounding
"thin" by moronic cone speaker addicts.



........... Phil