Description

Envelope follower unit generator emmulating a Perkin Elmer Vactrole VTL5C3/2.

Syntax

ares vactrol asig [iup, idown]

Initialisation

iup -- The rise time of the filter, which defaults to 20,

idown -- The fall time of the filter, which defaults to 3000,

Performance

asig -- The signal from which to extract the envelope.

Examples

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

<CsoundSynthesizer>
<CsInstruments>
        nchnls = 2
        0dbfs = 1
        
    instr 1
        a1 lfo 0.3, 1, 4
        a2 vactrol a1
        a3 oscili 2, 440
           out     a1*a3,a2*a3
     endin
                    
</CsInstruments>
<CsScore>
    i1 0 3
    e
</CsScore>
</CsoundSynthesizer>

This opcode can reduce zipper noise produced from complex envelope tracking as it smooths the transitions.

Credits