butterbp butterbp butterbp A band-pass Butterworth filter. Implementation of a second-order band-pass Butterworth filter. This opcode can also be written as butbp. ares butterbp asig, xfreq, xband [, iskip] iskip (optional, default=0) -- Skip initialization if present and non-zero. These filters are Butterworth second-order IIR filters. They are slightly slower than the original filters in Csound, but they offer an almost flat passband and very good precision and stopband attenuation. asig -- Input signal to be filtered. xfreq -- Cutoff or center frequency for each of the filters. xband -- Bandwidth of the bandpass and bandreject filters. Here is an example of the butterbp opcode. It uses the file butterbp.csd. See the sections Real-time Audio and Command Line Flags for more information on using command line flags. butterbr, butterhp, butterlp Author: &nameparis; MIT, Cambridge 1995 Existed in 3.30 Audio rate parameters introduced in version 6.02 October 2013.