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On 14.11.2010 03:40, Mathieu Bouchard wrote:
<blockquote
cite="mid:alpine.DEB.2.00.1011132138340.21837@paik.artengine.ca"
type="cite">On Sat, 13 Nov 2010, Mathieu Bouchard wrote:
<br>
<br>
<blockquote type="cite">On Wed, 10 Nov 2010, - wrote:
<br>
<br>
<blockquote type="cite">haut-parleur-doppler.pd is the original
file from Martin,
<br>
</blockquote>
[...]
<br>
<blockquote type="cite">Please correct me if I'm wrong
somewhere.
<br>
</blockquote>
<br>
Yes, that file is from me and not from Martin. (but that's just
a few kilometres off)
<br>
</blockquote>
<br>
(Doh, I was thinking about a different Martin. In any case, the
file comes from me.)
<br>
</blockquote>
thought you were joking...<br>
<br>
in your previous mail you wrote<br>
<blockquote
cite="mid:alpine.DEB.2.00.1011101427230.21837@paik.artengine.ca"
type="cite">It remains consonant to the ear so easily simply
because it only produces harmonics. <br>
</blockquote>
did you speak about the "doppler" distortion? true doppler
distortion is harmonic for a single sine wave, but not for 2 or more
sines of different frequencies. It's the same effect known as
frequency modulation, in this case a signal being its own carrier.
The difficulty in prediction of a spectrum is that the carrier is an
always changing mix of frequencies and not a single sine wave like
for a radio station transmitter or in the most simplest case of
frequency modulation synthesizers, but it is pretty easy to find out
it is non harmonic by listening...<br>
<br>
I want to add that the vd~ approach is not the "perfect
implementation" for the above described frequency modulatuon. the
carrier is delayed against the modulating signal a bit. Like this it
simulates a moving listener instead a moving sound source. Also for
a single sine wave the change of the spectrum differs by variation
of the delay.<br>
<br>
A more close to reality simulation which does only fm without delay
requires a variable (interpolating?) write into the delayline.
Unfortunately I don't know of such externals already existing.
However I don't expect the effects being very different from the vd~
method. A slow 20Hz sinewave modulating some high frequencies will
not sound very different if the 20Hz is delayed or not. A 20 hz
sound will have a duration which is much longer that the delay.<br>
<br>
Martin<br>
<br>
<br>
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