There are some patches with a fixed C note. I seems its currently not possible to archive this with the current midi plugins. Maybe this can be added? So we can use it for VST instruments.
I used protoplug to archive this, currently as workaound. I build my own little midi script: https://gist.github.com/ryrun/0649eb5fbcef9cc21053ea5e2a1cf994
I've been thinking about this recently as well. It is currently only a feature within Guru Sampler allowing you to define a set pitch. I do a lot of pad work (pads, piano with pads) and would like to have the ability for a constant pitch from other VSTs. Combine with a macro knob, I can bring that sound in/out during live performance. I do really like this feature in Guru Sampler. It is one of the Unify features that makes it unique to me.
Ableton Live 10, Omnisphere, Native Instruments (Pianos), Spire, Hammer + Waves, Heavyocity (Ascend), Diva, Alchemy 1.55, Unify
Thank you so much for alerting me to ProtoPlug. I had wanted to provide a way for users to create their own custom MIDI effects, and it seems it already exists: https://www.osar.fr/protoplug/. I will get in touch with the author right away!
I agree that a "convert all pitches to fixed pitch" function would be useful. I'll look into adding this to one of Unify's built-in MIDI effects in future.
