Hi @Apoxode and thanks for the recommendation. Piano sounds are made by a multiplatform application called Pianoteq by Modartt (https://www.pianoteq.com/).

I record my MIDI track on Reaper and send MIDI data directly to Pianoteq an then record the audio output of Pianoteq back to an audio track inside Reaper.

I think I get it — so you’re entering the notes like code into Reaper, which then uses Pianoteq to perform into back into Reaper. That’s kind of how I do it too with mods. Thanks!

:)