Combining / "morphing" sounds by modulation?

I’m looking for techniques to combine two dissimilar sounds for a sound effect. Simple approaches like combining them and playing with the envelopes and equalization are not not working well. I found some nyquist code for a ring modulation and tried using that to add in a bit of the sum and difference, thinking it might help blend it a bit, but I don’t really know what I’m doing :slight_smile:

My questions are:

  1. Are there techniques for combining sounds using nyquist that I should try?
  2. Are there other plugins that implement sound “morphing” or interpolation of some kind based on the direct waveforms or spectrums?
  3. Is there a way in Audacity or with nyquist code to map the envelope of one sound to another?
  4. Is there a way in audacity or with nyquist code to map the spectrum-envelope of one sound to a dynamic filter to be applied to another sound?

If none of these exist I am thinking about trying to write #3 and #4… not sure how easy they’d be using nyquist (which I’m not that familiar with) but I think I could do it with an audio processing library in another language.


There are many possible approaches (possibly limitless).
Could you narrow it down a bit? What are the sounds, and what is this for?

You’re looking for an "envelope follower" …

Steve’s “dynamic mirror” plugin will also do that.

Vocoder does that.

At the moment I’m trying to combine a cat meow and a rasping sound to create a cat-monster roar… i.e. imagine a giant cat roaring in a godzilla like way :slight_smile:

I’m hoping the envelope follow and vocoder mentioned above will help in combination with some regular mixing.


You could try using the “Sliding Time Scale / Pitch Shift” effect to lengthen the “meow” and progressively lower its pitch, and crossfade that with your “cat-monster roar”.

If you don’t yet have a “cat-monster” sound, you may be able to use or adapt a sound from