Hi Ok, I'm interested in getting some basic filtering going, first maybe just a simple low pass filter. So I received my copy of "Real Sound Synthesis". Section 3.9 suggests a low pass filter could be realized with a one-zero filter with "a" set between 0 and 1. Looking at http://chuck.cs.princeton.edu/doc/program/ugen_full.html#OneZero I don't see any "a", and where in the book can I read about b0 and b1. Moreover I wasn't able to locate any example code using OneZero, so if someone could provide me with a (couple of) simple example(s), I'd really appreciate it... -- peace, love & harmony Atte http://www.atte.dk | quartet: http://www.anagrammer.dk http://www.atte.dk/gps | compositions: http://www.atte.dk/compositions