shaker
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## shaker

shaker — Sounds like the shaking of a maraca or similar gourd instrument.

## Description

Audio output is a tone related to the shaking of a maraca or similar gourd instrument. The method is a physically inspired model developed from Perry Cook, but re-coded for Csound.

## Syntax

    ares shaker kamp, kfreq, kbeans, kdamp, ktimes [, idecay]

## Initialization

idecay -- If present indicates for how long at the end of the note the shaker is to be damped. The default value is zero.

## Performance

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

kamp -- Amplitude of note.

kfreq -- Frequency of note played.

kbeans -- The number of beans in the gourd. A value of 8 seems suitable.

kdamp -- The damping value of the shaker. Values of 0.98 to 1 seems suitable, with 0.99 a reasonable default.

ktimes -- Number of times shaken.

| Note
The argument knum was redundant, so it was removed in version 3.49.

## Examples

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

Example 938. Example of the shaker 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
    ; Audio out   Audio in    No messages
    -odac           -iadc     -d     ;;;RT audio I/O
    ; For Non-realtime ouput leave only the line below:
    ; -o shaker.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
    kfreq	line p4, p3, 440
       a1 shaker 10000, kfreq, 8, 0.999, 100, 0
       out a1
    endin

    </CsInstruments>
    <CsScore>

    i 1 0 1 440
    i 1 + 1 4000

    e
    </CsScore>
    </CsoundSynthesizer>

## Credits

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

New in Csound version 3.47

Fixed the example thanks to a message from Istvan Varga.

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