Hi, I’m just a bit confused about something (I don’t really have an understanding of FM). When I use KBD as the FM source for a filter, what’s actually happening?? As far as I can tell I haven’t routed any signals to the filter, as opposed to selecting an engine as a source. I’d like to understand how the filter is taking KBD information and affecting the sound.
Thank you
I know the effect it has but let me try to describe it:
Using the keyboard to affect the filter, scales the FM applied to the filter. There is less FM as you press lower notes and more as you press higher with the overall amount variable. So, sounds may sound “brighter” as you go up the keyboard. In its most basic implementation it can offset the tendency for sounds to become duller sounding as you play higher notes. This effect is not the same as applying keyboard scaling to the filter cutoff itself and the two processes will yield different results.
Note that the keyboard scaling can be modified in the Keyboard Tab. You could for example reverse this effect so that lower notes are “brighter” than higher notes or dip/boost in the middle of the keyboard.
Its hard to explain and its best to experiment with it.
Be aware that you will have to decrease the filter cutoff to start hearing the effect.
Thanks for your reply!
This makes sense, but I’m still confused as to what signal is modulating the filter, vary as it may. I might have a misconception about what FM modulation is. I understand that the KBD is affecting the modulation strength, but what is the source signal of the modulation?
If I understand it correctly (and I dont pretend to be an authority), then it is the selected source applying FM to the Filter Cutoff. In the case of selecting Keyboard, the values applied according to the keyboard output which is, by default, linear from 0 - Max (whatever that is).
It may be easier to understand if you select an LFO as a source rather than Keyboard and play with the rate, waveform and smooth parameter with Unipolar selected instead of Bipolar. You can see/hear the cyclic nature of the LFO affecting the Filter Cutoff FM.
I am probably not explaining it as best as possible but I have to found any other explanation on the Web nor the manual.