Techniques for modulating one sound from another

Lately I have been very interested in different ways a sound can be modulated by another. I was wondering if anyone here has any tips for different techniques for doing this?

Here are some I know already:

Envelope follower - using the volume of one sound to modulate parameters on the other one. F.ex. sidechain compression and gate, modulating filter cutoff etc.

Triggering - Using the transients of the sounds to trigger different messages, stages in a sequencer, etc.

Using a vocoder to follow the volume envelopes in different frequency ranges.

Any tips for any more techniques to try out?


Frequency and amplitude modulation and ring modulation are other ways which are very direct. Frequency modulation often implies you are generating the waveform but ring modulation can work between any pair of signals and is closely related to amplitude modulation.

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Any sort of effect with a side chain input is using one signal to modulate another. A very low pass filtered form of one signal (i.e slew limited) could probably be used as a low frequency modulation source too, where the thing you are modulating can’t handle audio rate.

I’ve always wanted to know exactly what is going on inside morph:

Just related…

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read out the amplitude with an envelope follower and set several threshold points with a comparator

The warps manual is pretty interesting even if you don’t have one (section that discusses the different algorithms is particularly relevant).


@walker’s “Timber FARM” series of videos, as well as plenty of other videos on the Make Noise channel, give plenty of examples of various ways to modify sounds with other sounds.


Trevor Wishart’s Audible Design book includes many approaches: (Sound morphing is a big interest for him, before computers he was developing tape techniques for morphing as well)

Edit: for example, his voice transforming into bees and back again:


Spectral Mutation in Soundhack
by Larry Polansky and Tom Erbe

Larry Polansky’s mutation functions (Polansky and McKinney, 1991; Polansky, 1992) are generalized morphological transformations which create mutations “between” morphologies (ordered sets). The mutation functions, originally designed for higher-level morphologies (such as melodies, durations series or statistical profiles of a parametric interval over time), considers intervals between elements of a morphology, and separate those intervals into magnitude and sign (direction).
Each of the mutation functions “pastes” or interpolates, in a different way, the sign or magnitude of one morphology into the sign or magnitude of the other, creating a third morphology which is some measurable combination of the two sources. In Soundhack Version 0.8 and above, the mutation functions are implemented in the spectral domain, where the individual FFT frames of soundfiles are considered to be the morphologies.


I have no idea what algorithms are in Morph 2, but it’s my favorite tool for combining two sources in interesting ways.

More generally, any mathematical function of two variables can be used to combine (convolve?) two sources. Eg, multiplication = ring modulation. I also like max, min, and division (if you want really noisy results).

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