GEN09
Prev | Score Statements and GEN Routines | Next

## GEN09

GEN09 — Generate composite waveforms made up of weighted sums of simple sinusoids.

## Description

These subroutines generate composite waveforms made up of weighted sums of simple sinusoids. The specification of each contributing partial requires 3 p-fields using GEN09.

## Syntax

    f # time size 9 pna stra phsa pnb strb phsb ...

## Initialization

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 (0-360).

| Note
These subroutines generate stored functions as sums of sinusoids of different frequencies. The two major restrictions on GEN10 that the partials be harmonic and in phase do not apply to GEN09 or GEN19. In each case the composite wave, once drawn, is then rescaled to unity if p4 was positive. A negative p4 will cause rescaling to be skipped.

## Examples

Here is an example of the GEN09 routine. It uses the files gen09.csd.

Example 1103. Example of the GEN09 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
    -odac     ;;;realtime audio out
    ;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
    ; For Non-realtime ouput leave only the line below:
    ; -o gen09.wav -W ;;; for file output any platform
    </CsOptions>
    <CsInstruments>

    sr = 44100
    ksmps = 32
    nchnls = 2
    0dbfs  = 1

    gi1 ftgen 1,0,2^10,9,  1,3,0,   3,1,0, 9,0.333,180		;an approximation of a square wave
    gi2 ftgen 2,0,2^10,9,  1,3,180, 3,1,0, 9,0.333,0		;same values as gi1, except some phase values
    gi3 ftgen 3,0,2^10,9,  1, .4, 0,   2.2, .5, 0,   3.8, 1, 0	;inharmonic, but does not sound well --> wave does not end at same point as where it begins --> artefacts
    gi4 ftgen 4,0,2^10,9,  10, .4, 0,   22, .5, 0,   38, 1, 0	;the same proportions, but value of partial number is multiplied 10 times -->the sound is much clearer,
    								;because the sudden "jump" like the one in gi3 will pop up only once in 10 repetitions

    instr 1

    kamp = .6
    kcps = 220
    ifn  = p4

    asig poscil kamp, kcps*p5, ifn
         outs   asig,asig

    endin
    </CsInstruments>
    <CsScore>

    i 1 0 2 1 1	;subtle difference between table 1 and 2
    i 1 3 2 2 1
    i 1 7 2 3 1	;big difference between table 3 and 4
    i 1 10 2 4 .1	;p5 has to compensate for the 10 repetitions of gi4 as opposed to gi3 to get the same pitch

    e
    </CsScore>
    </CsoundSynthesizer>

These are the diagrams of the waveforms of the GEN09 routines, as used in the example:

gi1 ftgen 1,0,2^10,9, 1,3,0, 3,1,0, 9,0.333,180 - approximation of a square wave

gi2 ftgen 2,0,2^10,9, 1,3,180, 3,1,0, 9,0.333,0 - same values as gi1, except phase value

gi3 ftgen 3,0,2^10,9, 1,2,0, 3,2,0, 9,0.333,180 - inharmonic partials, but with distortion due to the sudden jump in ending and beginning of the wave

gi4 ftgen 4,0,2^10,9, 1,2,180, 3,2,0, 9,0.333,0 - same ratio as gi3, except with less artefacts

## See Also

GEN10, GEN19

Prev | Up | Next
GEN08 | Home | GEN10