GEN18
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## GEN18

GEN18 — Writes composite waveforms made up of pre-existing waveforms.

## Description

Writes composite waveforms made up of pre-existing waveforms. Each contributing waveform requires 4 pfields and can overlap with other waveforms.

## Syntax

    f # time size 18 fna ampa starta finisha fnb ampb startb finishb ...

## Initialization

size -- number of points in the table. Must be a power-of-2 (see f statement).

fna, fnb, etc. -- pre-existing table number to be written into the table.

ampa, ampb, etc. -- strength of wavefoms. These are relative strengths, since the composite waveform may be rescaled later. Negative values are permitted and imply a 180 degree phase shift.

starta, startb, etc. -- where to start writing the fn into the table.

finisha, finishb, etc. -- where to stop writing the fn into the table. The last available location is the power of two - 1.

## Examples

    f 1  0  4096  10  1
    f 2  0  1024  18  1  1  0  511  1  1  512  1023

f2 consists of two copies of f1 written in to locations 0-511 and 512-1023.

Here is an example of the GEN18 routine. It uses the files gen18.csd.

Example 1140. An example of the GEN18 routine.

    <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 gen18.wav -W ;;; for file output any platform
    </CsOptions>
    <CsInstruments>

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

    instr 1

    ifn   = p4
    ilen  = ftlen(ifn)
    aphase  phasor 220
    asig    tablei aphase*ilen, ifn
            outs   asig, asig

    endin
    </CsInstruments>
    <CsScore>

    f 1 0 4096 10 1                                         ;sine
    f 2 0 4096 10 1 0.5 0.3 0.25 0.2 0.167 0.14 0.125 .111  ;sawtooth
    f 3 0 4096 11 10 5 2                                    ;cosine partials

    f 11 0 8192  18 1 1 0 4095 2 1 4096 8191    ;sine+sawtooth
    f 12 0 8192  18 1 1 0 4095 3 1 4096 8191    ;sine+cosine partials
    f 13 0 1024  18 1 0.7 0 767 3 0.7 512 1023  ;sine+cosine partials overlapped, shorter table

    i 1 0 2 2    ;play sawtooth
    i 1 + 2 3    ;then cosine partials
    i 1 5 2 11   ;now sine+sawtooth
    i 1 + 2 12   ;and sine+cosine partials
    i 1 + 2 13   ;and sine+cosine partials overlapped, shorter table

    e
    </CsScore>
    </CsoundSynthesizer>

These are the diagrams of the waveforms generated by GEN18, as used in the example:

f 11 0 8193 18 1 1 0 4096 2 1 4097 8192 - composite waveform made up of a sine wave and a sawtooth

f 12 0 8192 18 1 1 0 4096 3 1 4097 8192 - composite waveform made up of a sine wave and a wave of cosine partials

f 13 0 1024 18 1 0.7 0 767 3 0.7 512 1023 - sine+cosine partials overlapped, also shorter table than f12

## Deprecated Names

GEN18 was called GEN22 in version 4.18. The name was changed due to a conflict with DirectCsound.

## Credits

Author: William “Pete” Moss
University of Texas at Austin
Austin, Texas USA
January 2002

New in version 4.18, changed in version 4.19

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