Thanks to Clemens for spotting an error in the implementation of the skf, it was a copy and paste error from the svf version where I didn't update the denominator in the code to be the correct one solved for. I've updated it now:
http://cytomic.com/files/dsp/SkfLinearTrapOptimised2.pdf All the best, Andy -- dupswapdrop -- the music-dsp mailing list and website: subscription info, FAQ, source code archive, list archive, book reviews, dsp links http://music.columbia.edu/cmc/music-dsp http://music.columbia.edu/mailman/listinfo/music-dsp