Unfortunately, it isn’t simply a matter of mapping modulation wheel to velocity. For starters, that’s a fairly complex transformation. Secondly, velocity is already being used to alter the attack samples of the note.

A better way to do the would be to map your foot controller to the modulation wheel (or vice versa in the software). This way you would free up your left hand, but still be able to control the volume of the sound.

The thing is, when emulating a non-keyboard sound, the volume of the sound is not a function of how hard the note is hit by the instrument in the first place, but by the wind pressure of the player, or the strength of the bowing etc. DURING the note’s length.

If you try this, you will find that you now have considerable control of the note AFTER you have hit the note, just like a real wind player, not just control over its volume the minute that you start the note.

Ideally, you might use a breath controller to control the sound, which would give you the most accurate control over the notes’ dynamics, but few of us have those anymore! But if you can practice breathing, or singing and try to make your foot follow your lungs, you will find that you are making a really authentic emulation of the instrument…

There’s a lot to be learned by trying to sing along with a horn sound you are trying to emulate. For starters, you immediately know when you are going to have to take a breath in the line you are playing, because our lungs are not infinite LOL. Plus, in my opinion, you tend to make far more natural sounding phrases. No matter how well or poorly we sing, there is always that brain to voice connection that we seldom achieve in our brain to fingers connection! Sing along with your solo… You will be amazed at how more natural your playing starts to sound if you are emulating a wind instrument!