The MIDI source is a powerful modulation source if you want more control over FabFilter Saturn
using a MIDI keyboard or MIDI control knobs. Note that you first need to route data from a MIDI
track to Saturn in your host.
To add a MIDI source as a modulation source, click the + button in the
source selection bar and click New MIDI
Normally the MIDI source lets you use MIDI input such as velocity, pitch bend and modulation
wheel to influence any parameter that can be modulated.
... but when you set the input selection to Controller, it lets you use any MIDI controller
as a modulation source.
The response curve can be adjusted to get the desired control over the MIDI source output.
For example, when used with velocity as MIDI source the linear, exponential, logarithmic,
square, square root or sine curves make great dynamic differences.
Using a MIDI source is different from MIDI Learn because there is
no direct control of a knob via MIDI but it uses a modulation slot instead. This way you can add
modulation to an already modulated destination. Or you can use the full rotation of a knob while
actually modulating a smaller range. This can be a good way to control say, a band level or EG
attack for which you sometimes want to make small changes with great precision.
At the top right of the source interface, the Presets button provides access to the MIDI source section presets. The Remove button deletes the MIDI source. You can customize the
default MIDI source settings (used when creating a new MIDI source) by overwriting the predefined
Default section preset.
To let a sustain pedal control an envelope generator, use a MIDI
source. Set the input to Controller, and the controller number to 64. Now, drag the source drag button for the MIDI source to the hold control
point of the envelope generator, and set the slot level to maximum. Of course, you can also set
up more sophisticated behavior of the sustain pedal, for example by modulation the release
setting instead of hold: the possibilities are endless.
The VST 3 version of FabFilter Saturn doesn't support per-note aftertouch modulation.