There are two general methods of rendering dynamics in sample libraries, each with their own limitations:
- Note velocity means that multiple voices can have different dynamics. However, once the note has started there is no way of changing it while it is sounding. This is generally used for pianos and by GM-type sound libraries
- MIDI CC dynamics allow dynamics to change after a note has been struck (eg crescendo on a long note). However, all notes on that channel will respond to it so you can’t have multiple voices with separate dynamics on the same channel. This is used more commonly for sustaining instruments in many sound libraries.
In the expression map you’re using, you have note velocity dynamics, so it means that once the note has started, the crescendoes have no effect. If you switch the playback template to the HSSE+HSO (which uses a CC dynamic) then you will hear it play with dynamics, however you won’t be able to have different dynamics in the other voice.
In a future version we intend to allow independent voice playback, so that each voice can use a separate channel and hence can have its own dynamics.