Jim Carr wrote:

"Bob Cain" wrote in message
...

When you push on air, it moves and pushes on the air in
front of it but with some delay in the transfer. That's
what causes the speed of sound. The push propegates outward
from this bit of air to the bit in front of it and that's a
wave. Same when you pull on it.

Does that help?


Sorta. From what you're saying. the *origin* of each individual wave can
take place at any point within the throw of the diaphragm. Is that correct?

Not sure even how to define the origin of the wave in those
terms. Thanks for that. I just realized that the
assumptions which are being made about that are the flaw in
the intuitive description of "Doppler distortion."

Something that is ocuring dynamically is being described in
terms of a static piston in one sense and dynamically in
another. That doesn't work. The distance from the piston
to the the sensor isn't relevant to the argument if it is
riding the wave. In a way, it's effect is being included
twice if you do that. That's a no-no that will lead to
false prediction.

The flaw in the common argument for "Doppler distortion" has
proven very elusive but I think that this nails it. It
really is subtle which explains why it's been around so long.

I added rec.audio.pro to this because it's highly relevant
to the thread on this subject that is happening there.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein