A filter such that only frequencies present in both signal A and B pass through


Is there a name for what I'm describing? I suppose it could also be viewed as multiplying the amplitudes of matching frequencies from A and B. My goal is similar to a vocoder; I want to shape some synth-like wave to follow the frequencies of a vocal sample. Perhaps this is how vocoders already work, but I haven't seen any that allow you to provide your own modulation signal.


Posted 2016-07-16T09:53:19.707

Reputation: 13

For anybody who finds this through Google: There's a plugin that does this here: https://github.com/MaxBright/BrightConvolver

– Ott – 2016-10-13T13:30:19.703



Exactly, that's how vocoder and convolution reverbs work.

What you are after is multiplication in the frequency domain, which is equivalent to convolution in time domain, and that's also how it is generally called: convolution. When the modulator is an impulse response you get a reverb, when it's something stranger a vocoder.

Good software to experiment with it are PureData and Reaktor. I don't know, but I bet there are VSTs that let you provide the modulation signal. Search for convolver and/or convolution.


Posted 2016-07-16T09:53:19.707

Reputation: 126

Thank you! I didn't realize convolvers could do more than reverb. – Ott – 2016-07-17T19:46:49.780

1@Ott In theory, any linear operation can be done by a convolver. In practice that's not always the best way, as the length of the "impulse rensponse" needed to achieve cool results is easily very long (it implies latency). – darius – 2016-07-17T21:04:57.100