I can use most synths plugins with a foot switch pedal to hold notes, but some don't respond to it.
The pedal has two modes that output MIDI CC 64 with value 127 for on and 0 for off.
I am having this problem for a while and could never figured it out. I searched the Ableton forum, but no cigar.
My first idea was to re-assign the CC64 to CC 66 (Sostenuto Pedal on/off) which is also to supposed to hold notes. My best guess was to use the "Expression Monitor" that shows the pedal input under "Sustain", but I don't know how to forward it to the other CC 66. The question then is, if the plugin will react to CC 66.
So I am out of ideas. If anyone has an idea, it will be greatly appreciated and you will be my hero.

 

The sustain pedal has 2 modes? as in “switch” 0 & 127 or “continuous” 0-127? What pedal are you using? What synth are you using? What plug-in are you using? I assume you’re using Ableton as your DAW? BTW Sostenuto is different than sustain. Sostenuto only sustains notes that are currently playing at the time it’s engaged.

 

Last edited: Aug 17, 2023

Thanks so much Moogerfooger for answering, but guess what after all this time I have just accidentally found out why it didn't work.
In Newfangled Audio Pendulate there is this little MPE button. Guess what it did ;) In Plasmonic the MIDI mode had to be set from Standard to MPE. I guess all other synths are looking for MPE input by default, but not those. I am a bit embarrassed, but maybe that helps someone else with the same problem.

 

Absolutely no reason to be embarrassed brother. Glad u found the solution