hi all,
i'm currently using biquad filters (i'm getting the settings from iemlib's lowpass, highpass (...) externals). i consider to change my patch to use svf~ from the cyclone library.
does anyone know, which algorithm is more expensive in terms of cpu time? and are there any mayor differences in the characteristics of these two filter types?
thanks a lot...
Tim mailto:TimBlechmann@gmx.de ICQ: 96771783 -- The only people for me are the mad ones, the ones who are mad to live, mad to talk, mad to be saved, desirous of everything at the same time, the ones who never yawn or say a commonplace thing, but burn, burn, burn, like fabulous yellow roman candles exploding like spiders across the stars and in the middle you see the blue centerlight pop and everybody goes "Awww!" Jack Kerouac
hi Tim,
while coding cyclone's filters, I was mainly concerned about matching impulse responses of msp counterparts (I believe, that currently most of them match 100% for the entire domain of control parameters... with svf~, however, there is still some difference at high Q -- this one is tricky to clone, due to a nonlinear component thrown into the formula).
In theory, a plain svf performs slightly better than four separate filters (lowpass, highpass, bandpass, notch). Cyclone's svf is not a plain svf, but since it does no oversampling, and calculates the coefficients once per block, the hope is it does perform well (although the only test I ever did, apart from checking that it is useable, was estimating the oversampling costs).
Comparing to the biquad~ internal, svf~ does have an overhead, obviously -- there is always a price for allowing to control a filter with signal input (both q and f may be modulated).
Krzysztof
Tim Blechmann wrote: ...
i'm currently using biquad filters (i'm getting the settings from iemlib's lowpass, highpass (...) externals). i consider to change my patch to use svf~ from the cyclone library.
does anyone know, which algorithm is more expensive in terms of cpu time? and are there any mayor differences in the characteristics of these two filter types?
On Fri, 27 Feb 2004, Tim Blechmann wrote:
hi all,
i'm currently using biquad filters (i'm getting the settings from iemlib's lowpass, highpass (...) externals). i consider to change my patch to use svf~ from the cyclone library.
does anyone know, which algorithm is more expensive in terms of cpu time? and are there any mayor differences in the characteristics of these two filter types?
I think they are completely different. Biquad~ at least is not really good if you want to control in the signal domain. The lowpass etc externals implement the filters from here:
http://www.harmony-central.com/Computer/Programming/Audio-EQ-Cookbook.txt written by Robert Bristow-Johnson
Then the last time I saw them they were written by me, and not part of the iemlib, but how knows, ... in reality the hard work was done by Robert Bristow-Johnson.
Guenter
I think they are completely different. Biquad~ at least is not really good if you want to control in the signal domain. The lowpass etc externals implement the filters from here:
http://www.harmony-central.com/Computer/Programming/Audio-EQ-Cookbook.txt written by Robert Bristow-Johnson
i'll have a look at it...
Then the last time I saw them they were written by me, and not part of the iemlib, but how knows, ... in reality the hard work was done by Robert Bristow-Johnson.
sorry for that ... i must have mixed them up with iemlib's filter abstractions ...
cheers...
Tim mailto:TimBlechmann@gmx.de ICQ: 96771783 -- The only people for me are the mad ones, the ones who are mad to live, mad to talk, mad to be saved, desirous of everything at the same time, the ones who never yawn or say a commonplace thing, but burn, burn, burn, like fabulous yellow roman candles exploding like spiders across the stars and in the middle you see the blue centerlight pop and everybody goes "Awww!" Jack Kerouac
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guenter geiger -
Krzysztof Czaja -
Tim Blechmann