Hi, I just noticed that the 'set' method doesn't seem to work properly with HPF. the following code shows the difference between using 'set' and 'freq' Noise noise => HPF filter => dac; 100 => float f; filter.Q(1); while( true ) {     f + 100 => f;     if( f > 5000 )     {         100 => f;     }     // swap between filter.freq and filter.set to check the difference     filter.freq(f);     //filter.set( f, 1 );     0.1::second => now; } I'll report this on github as well. Cheers, Mario -- Electronic Musician, Creative Coder, QA Engineer https://vimeo.com/creativecodingsalerno http://mbuoninfante.tumblr.com/ https://github.com/mariobuoninfante https://bitbucket.org/mariobuoninfante/