octave — Calculates a factor to raise/lower a frequency by a given amount of octaves.
The value returned by the octave function is a factor. You can multiply a frequency by this factor to raise/lower it by the given amount of octaves.
Here is an example of the octave opcode. It uses the file octave.csd.
Example 671. Example of the octave 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 ;;;realtime audio out ;-iadc ;;;uncomment -iadc if realtime audio input is needed too ; For Non-realtime ouput leave only the line below: ; -o octave.wav -W ;;; for file output any platform </CsOptions> <CsInstruments> sr = 44100 ksmps = 32 nchnls = 2 0dbfs = 1 instr 1 iroot = 440 ; root note is A above middle-C (440 Hz) koct lfo 5, 1, 5 ; generate sawtooth, go from 5 octaves higher to root koc = int(koct) ; produce only whole numbers kfactor = octave(koc) ; for octave knew = iroot * kfactor printk2 knew asig pluck 1, knew, 1000, 0, 1 asig dcblock asig ;remove DC outs asig, asig endin </CsInstruments> <CsScore> i 1 0 5 e </CsScore> </CsoundSynthesizer>
Its output should include lines like:
i1 3520.00000 i1 1760.00000 i1 880.00000 i1 440.00000 i1 7040.00000 i1 3520.00000 i1 1760.00000 i1 880.00000 i1 440.00000 .......