These subroutines generate composite waveforms made up of weighted sums of simple sinusoids. The specification of each contributing partial requires 4 p-fields using GEN19.
size -- number of points in the table. Must be a power of 2 or power-of-2 plus 1 (see f statement).
pna, pnb, etc. -- partial no. (relative to a fundamental that would occupy size locations per cycle) of sinusoid a, sinusoid b, etc. Must be positive, but need not be a whole number, i.e., non-harmonic partials are permitted. Partials may be in any order.
stra, strb, etc. -- strength of partials pna, pnb, etc. These are relative strengths, since the composite waveform may be rescaled later. Negative values are permitted and imply a 180 degree phase shift.
phsa, phsb, etc. -- initial phase of partials pna, pnb, etc., expressed in degrees.
dcoa, dcob, etc. -- DC offset of partials pna, pnb, etc. This is applied after strength scaling, i.e. a value of 2 will lift a 2-strength sinusoid from range [-2,2] to range [0,4] (before later rescaling).
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Here is a simple example of the GEN19 routine. It uses the file gen19.csd. It will generate a nice bell curve, here is its diagram:
Diagram of the waveform generated by GEN19.
Example 17. A simple example of the GEN19 routine.
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 ; Audio out Audio in -odac -iadc ;;;RT audio I/O ; For Non-realtime ouput leave only the line below: ; -o gen19.wav -W ;;; for file output any platform </CsOptions> <CsInstruments> ; Initialize the global variables. sr = 44100 kr = 4410 ksmps = 10 nchnls = 1 ; Instrument #1. instr 1 ; Create an index over the length of our entire note. kcps init 1/p3 kndx phasor kcps ; Read Table #1 with our index. ifn = 1 ixmode = 1 kval table kndx, ifn, ixmode ; Generate a sine waveform, use our Table #1 value to ; vary its frequency by 100 Hz from its base frequency. ibasefreq = 440 kfreq = kval * 100 a1 oscil 20000, ibasefreq + kfreq, 2 out a1 endin </CsInstruments> <CsScore> ; Table #1: a bell curve (using GEN19). f 1 0 16384 -19 1 1 260 1 ; Table #2, a sine wave. f 2 0 16384 10 1 ; Play Instrument #1 for 3 seconds. i 1 0 3 e </CsScore> </CsoundSynthesizer>