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valpass

Variably reverberates an input signal with a flat frequency response.

Syntax

ares = valpass(asig, krvt, xlpt, imaxlpt [, iskip] [, insmps])

ares valpass asig, krvt, xlpt, imaxlpt [, iskip] [, insmps]

Initialization

imaxlpt -- maximum loop time for klpt

iskip (optional, default=0) -- initial disposition of delay-loop data space (cf. reson). The default value is 0.

insmps (optional, default=0) -- delay amount, as a number of samples.

Performance

krvt -- the reverberation time (defined as the time in seconds for a signal to decay to 1/1000, or 60dB down from its original amplitude).

xlpt -- variable loop time in seconds, same as ilpt in comb. Loop time can be as large as imaxlpt.

This filter reiterates input with an echo density determined by loop time xlpt. The attenuation rate is independent and is determined by krvt, the reverberation time (defined as the time in seconds for a signal to decay to 1/1000, or 60dB down from its original amplitude). Its output will begin to appear immediately.

Examples

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

Example of the valpass opcode.
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<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 valpass.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

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

instr 1 

krvt = 1.5
klpt line p4, p3, p5
imaxlpt = .1

a1 diskin2 "fox.wav", 1
a1 valpass a1, krvt, klpt, imaxlpt
a2 valpass a1, krvt, klpt*.5, imaxlpt
   outs a1, a2  

endin
</CsInstruments>
<CsScore>

i 1 0 5 .01 .2
e
</CsScore>
</CsoundSynthesizer>

Here is another example of the valpass opcode. It uses the file valpass-2.csd.

Second example of the valpass opcode.
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<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 valpass-2.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

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

giSine ftgen 0, 0, 65536, 10, 1                 ;sine wave

instr 1

asig diskin2 "drumsMlp.wav", 1, 0, 1
krvt line 0.01, p3, p3                          ;reverb time
adepth = p4                                     ;sine depth 
krate = 0.3                                     ;sine rate (speed)
adel oscil 0.5, krate, giSine                   ;delay time oscillator (LFO)
adel = ((adel+0.5)*adepth)                      ;scale and offset LFO
aout valpass asig, krvt, adel*0.01, 0.5
     outs aout, aout

endin
</CsInstruments>
<CsScore>

i1 0  10 1
i1 11 10 5      
e
</CsScore>
</CsoundSynthesizer>

See also

Reverberation

Credits

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