combinv — Reverberates an input signal with a “colored” frequency response.
ilpt -- loop time in seconds, which determines the “echo density” of the reverberation. This in turn characterizes the “color” of the combinv filter whose frequency response curve will contain ilpt * sr/2 peaks spaced evenly between 0 and sr/2 (the Nyquist frequency). Loop time can be as large as available memory will permit. The space required for an n second loop is n*sr floating or double numbers (usually 4 or 8 bytes). Delay space is allocated and returned as in delay.
iskip (optional, default=0) -- initial disposition of delay-loop data space (cf. reson). The default value is 0.
insmps (optional, default=0) -- delay amount, as a number of samples.
krvt -- the reverberation time (defined as the time in seconds for a signal to decay to 1/1000, or 60dB down from its original amplitude).
This filter reiterates input with an echo density determined by loop time ilpt. The attenuation rate is independent and is determined by krvt, the reverberation time (defined as the time in seconds for a signal to decay to 1/1000, or 60dB down from its original amplitude). Affect from a combinv filter will appear only after ilpt seconds.
Here is an example of the combinv opcode. It uses the file combinv.csd.
Example 128. Example of the combinv opcode.
See the sections Real-time Audio and Command Line Flags for more information on using command line flags.
<CsoundSynthesizer> <CsOptions> ; Select audio/midi flags here according to platform -odac ;;;RT audio out ;-iadc ;;;uncomment -iadc if RT audio input is needed too ; For Non-realtime ouput leave only the line below: ; -o comb.wav -W ;;; for file output any platform </CsOptions> <CsInstruments> sr = 44100 ksmps = 32 nchnls = 2 0dbfs = 1 instr 1 kcps expon p5, p3, p4 asig oscil3 0.3, kcps, 1 krvt = 3.5 ilpt = 0.1 aleft combinv asig, krvt, ilpt outs aleft, asig endin </CsInstruments> <CsScore> f1 0 4096 10 1 i 1 0 3 20 2000 e </CsScore> </CsoundSynthesizer>