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wgbow

Creates a tone similar to a bowed string.

It uses a physical model developed from Perry Cook, but re-coded for Csound.

Syntax

ares wgbow kamp, kfreq, kpres, krat, kvibf, kvamp [, ifn] [, iminfreq]

Initialization

ifn -- optional table of shape of vibrato, defaults to a sine table.

iminfreq (optional) -- lowest frequency at which the instrument will play. If it is omitted it is taken to be the same as the initial kfreq. If iminfreq is negative, initialization will be skipped.

Performance

A note is played on a string-like instrument, with the arguments as below.

kamp -- amplitude of note.

kfreq -- frequency of note played.

kpres -- a parameter controlling the pressure of the bow on the string. Values should be about 3. The useful range is approximately 1 to 5.

krat -- the position of the bow along the string. Usual playing is about 0.127236. The suggested range is 0.025 to 0.23.

kvibf -- frequency of vibrato in Hertz. Suggested range is 0 to 12

kvamp -- amplitude of the vibrato

Examples

Here is an example of the wgbow opcode. It uses the file wgbow.csd.

Example of the wgbow opcode.
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<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
-odac     ;;;realtime audio out
;-iadc    ;;;uncomment -iadc if RT audio input is needed too
; For Non-realtime ouput leave only the line below:
; -o wgbow.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

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

instr 1

kpres = p4                                                      ;pressure value
krat = p5                                                       ;position along string
kvibf = 6.12723

kvib  linseg 0, 0.5, 0, 1, 1, p3-0.5, 1                         ; amplitude envelope for the vibrato.           
kvamp = kvib * 0.01
asig  wgbow .7, 55, kpres, krat, kvibf, kvamp, 1
      outs asig, asig

endin
</CsInstruments>
<CsScore>
f 1 0 2048 10 1 ;sine wave

i 1 0 3 3 0.127236
i 1 + 3 5 0.127236
i 1 + 3 5 0.23

e
</CsScore>
</CsoundSynthesizer>

See also

Waveguide Physical Modeling

Credits

Author: John ffitch (after Perry Cook)
University of Bath, Codemist Ltd.
Bath, UK

New in Csound version 3.47

ifn optional in version 6.06