On 5/10/15 3:42 PM, Matthias Puech wrote:
This is my first post on this list, although I have been reading it for quite
some time, with great interest.
welcum
I am a CS researcher in an unrelated field, but fascinated for as long as I
can remember by DSP and sound synthesis. Unfortunately my knowledge is still
basic, and now is the first time that I face real technical difficulties (while
implementing this: http://mqtthiqs.github.io/parasites/). Witness this question:
I have a recursive comb filter, implemented with a simple delay line of size N and feedback F in
[0..1]. If feedback is high and I "ping" it, it decays exponentially as it should, to
give the typical ringing effect. The decay time D is also proportional to N: if I double N, D is
also doubled. My question: what is the value of F depending on N that will give a constant D. In
other words, how can I "play" my comb filter on a scale à la Karplus-Strong and retain a
constant decay time?
Sorry if this sounds too trivial or if it is not the right place to ask. Don’t
hesitate to redirect me if needed or point me to references, I am eagerly
looking for basic literature.
it's not trivial and it's not in the basic lit.
lemme find and review my own notes/equations regarding that (i think i
titled it "Fun with Comb Filters"), and i'll get back on it. but to
tune your comb filters to arbitrary pitches, you will need a precision
tap delay line. maybe need to get familiar with the Nyquist/Shannon
Sampling and Reconstruction Theorem and the good ol' "sinc()" function.
--
r b-j r...@audioimagination.com
"Imagination is more important than knowledge."
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