[PD] convolution filter

Roman Haefeli reduzierer at yahoo.de
Thu Feb 3 02:52:17 CET 2005


i tried to create a convolution filter (if this is the correct
expression for what i want), but i failed. i want to filter an
audiosignal with an impulse response (e.g. of a room) or the transfer
function of a loudspeaker.
i read the docu  about 'fft and pd' from marius schebella
(http://www.parasitaere-kapazitaeten.net/Pd/fft_und_pd_en.htm) and i
tried the patch from page 5. when i use an impulse response, where the
first sample is 1 and the rest is 0, it works, which means that the
output of the convolution filter is the same as the input. but when i
change the position of the sample with value 1, i get bad glitches in
the sound. the same, when i use any other impulse responses than the
(dummy) one i described first.
i also tried the patch from page 10 (convolution filter) which is the
same as the pd-doc -> 4.fft-examples -> 08.convobros.pd. but this one
seems to work more as a vocoder than like what i want.
if somebody understands what i want and i am trying to explain --> hints
or links are very welcome. also if somebody have already made a patch to
generate reverberation with room impulse responses by convolution, i am
very interested.



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