On 14.11.2010 03:40, Mathieu Bouchard wrote:
On Sat, 13 Nov 2010, Mathieu Bouchard wrote:
On Wed, 10 Nov 2010, - wrote:
haut-parleur-doppler.pd is the original
file from Martin,
[...]
Please correct me if I'm wrong
somewhere.
Yes, that file is from me and not from Martin. (but that's just
a few kilometres off)
(Doh, I was thinking about a different Martin. In any case, the
file comes from me.)
thought you were joking...
in your previous mail you wrote
It remains consonant to the ear so easily simply
because it only produces harmonics.
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...
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.
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.
Martin