[PD] Building a compressor in PD?

Mathieu Bouchard matju at artengine.ca
Wed Nov 28 13:57:01 CET 2007

On Wed, 28 Nov 2007, Roman Haefeli wrote:

> hm.. don't quite know, how to answer this, i'd say yes and no. basically
> 'waveshaping' means adding non-linear distortions to a signal, a
> process, which enriches the frequency spectrum of the signal (->
> spectrum is altered).

Yes. Many waveshaping functions can be expressed as a sum of powers of the 
original signal. Each power of the signal is like convolving the spectrum 
repeatedly with itself. Any smoothly clipping waveshaper will be the sum 
of an infinite number of powers. Thus you're pretty much guaranteed to 
have an enriched spectrum as soon as you use a loud enough input.

> a waveshaper uses table look-up, so each input value has its 
> corresponding output value

a waveshaper can avoid using a table, and each input value would still 
have its corresponding output value. actually, i never think of 
waveshapers in terms of tables. that said, a plain table only gives you an 
output value for specific input values. [tabread4] pads the rest of input 
possibilities with a formula... so you pretty much never want to 
completely get rid of formulas anyway.

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| Mathieu Bouchard - tél:+1.514.383.3801, Montréal QC Canada

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