FM on recorded audio

[dkmayer]

@Aueh

Ive seen VST plugins or soft synths that have a FM option on inputs that are not just simple oscillators. The inputs i talk about dont have any frequency parameter you can access.

I elaborated on this topic here:

Frequency Modulation – Phase Modulation – Delay Modulation (FM / PM / DM)

Thinking again about these basic synthesis strategies, I wanted to see how to write them in equivalent ways in SC. Phase modulation is roughly the same as frequency modulation: it produces sidebands in the same way, and this is also the case for delay modulation. Delay modulation is practical because it enables FM-like modulation without knowing the source’s frequencies. Definitions: carr: carrier frequency mod: modulator frequency dev: deviation, maximum change of carrier index = dev / mod …

For sine waves, the modulations of frequency, phase and delay are basically equivalent, only the input has to be given in a different form, see the conversion formulas above and the limited usability of the index. With recorded output, you can work with rate modulation (as in your example) or phase modulation (BufRd), with an arbitrary incoming signal you can use delay modulation. In all of the latter cases you get the typical sideband effects.