[linux-audio-dev] [ann] guitar preamp plugin, v2

Tim Goetze tim at quitte.de
Wed Nov 5 06:25:20 EST 2003


Erik de Castro Lopo wrote:

>On Wed, 5 Nov 2003 10:54:58 +0100 (CET)
>Tim Goetze <tim at quitte.de> wrote:
>
>> i feel the need to clarify/correct myself: the filters employed are
>> not chebyshev designs, they were designed the same way as 'unmatched':
>> frequency response given, iteratively approximate the filter.
>> 
>> they do a lot better than chebys of the same order, but it's quite
>> impossible to recalculate their coefficients at runtime. if that is
>> demanded, the polyphase design probably wins easily.
>
>Tim, do you have any more info about this filter design procedure? I've
>currently got a nasty filter design problem that I'm looking for a 
>solution for.

second part of chapter 26, http://dspguide.com/ has the algorithm.
takes some fiddling for every filter you use it for, but it usually 
is worth the effort.

i have a python implementation of the algorithm if you like that 
better than BASIC (FFT and IIR work is done in a largish, somewhat
unpolished and unreleased-yet c++ lib of mine). 

tim



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