KarmaFX Forum

Hi,
been playing around with the FM controller module on the back end of a sampler - and being a bit thick-
what does the mod index control do? (apart from produce really cool sounds)

also it would be really nice to be able to allow two signals to be used for FM or PM, rather than using the controller module's own osc, i saw you mentioned a 'combiner' module in another thread and it would be really nice if it could allow FM/PM modulation between signals

Hi Hengy !!

Hengy wrote:Hi,
been playing around with the FM controller module on the back end of a sampler - and being a bit thick-
what does the mod index control do? (apart from produce really cool sounds)

Modulation index simply adjusts the amount of FM modulation.
You can think of FM as frequency modulated by e.g. a sine oscillator, where the sine freq is controlled by "ratio" and amplitude by "mod index". These are legacy names from back in the FM days, but are still used today.

You might also experiment by letting a HFO modulator control the frequency knob of a frequency controller. The hfo also has a simple FM mode, where you use the "amount" knob to control the modulation index.
The result is the same, but it might be a bit more illustrative since you can see the signal...

Hengy wrote:
...also it would be really nice to be able to allow two signals to be used for FM or PM, rather than using the controller module's own osc, i saw you mentioned a 'combiner' module in another thread and it would be really nice if it could allow FM/PM modulation between signals

Wiring two controllers in series will combine their control signal, so this should already be possible, but again, try to experiment with two HFO's (so the signals are mixed) fed into some freq knob, and see if this does the trick ?!

- KarmaFX