noise — A white noise generator with an IIR lowpass filter.
ioffset -- the delay before the first impulse. If it is negative, the value is taken as the number of samples, otherwise it is in seconds. Default is zero.
xamp -- amplitude of final output
kbeta -- beta of the lowpass filter. Should be in the range of 0 to 1.
The filter equation is:
y_n = sqrt(1-beta^2) * x_n + beta Y_(n-1)
where x_n is white noise.
Here is an example of the noise opcode. It uses the file noise.csd.
Example 243. Example of the noise 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 noise.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
kamp = 30000
; Change the beta value linearly from 0 to 1.
kbeta line 0, p3, 1
a1 noise kamp, kbeta
out a1
endin
</CsInstruments>
<CsScore>
; Play Instrument #1 for one second.
i 1 0 1
e
</CsScore>
</CsoundSynthesizer>