Research a mode where only 1 note sounds at the same time

[davidryan59]

There are currently 3 sustain modes:

• Note on for fixed time (Sustain ON)
• Note on, and then turns off when key lifted (Sustain OFF)
• Note on, and then turns off when same key pressed again (Sustain ON*)

Want a fourth setting, where only one note is played at the same time. Hence it makes the keyboard commutative, since when you hit multiple notes the playing note will be the product of their frequency shifts.

For this mode, don't have to keep creating and destroying audio nodes - can keep one (or more) oscillators in the background, on all the time, and control the note sound with gains etc.

Considerable reorganisation of the audio nodes and instrument. But probably an interesting output - single controllable note, like a violin or trumpet.