How to prevent sending СС messages from knobs directly to the instrument?

I got a problem that I didn’t have before. Previously, I myself assigned the knobs of my MIDI controller to the Ardour parameters, but now I noticed that some knobs change not only the parameter to which I explicitly assigned it, but also some other parameters of the Instrument.

For example: the 8th knob changes the pan (stereo balance) to the MIDI General synth.

Can I somehow disable the sending of CC messages from knobes to tools? I want to choose on my own which knobes change what.

Most MIDI CC messages (the kinds likely sent by your knobs) have predefined meanings. If they are received by a synth that wants to act on those meanings, it will, unless there is a way within the synth to turn off that behavior. There is certainly a MIDI CC pan message, for example, and it is quite likely that you have a knob which sends it.

The x42 plugins include a MIDI filter that I believe could be used to stop those messages from reaching the synth. But if you actually want to use them (for something else), then it’s a synth-specific question: how to stop this particular synth from responding to these messages.

I believe that with fluidsynth and the GM soundfont, this is not possible.

Somebody else may correct me.

Yes. MIDI Event Filter can Block Control Changes. Thanks.