Regarding sf2synth.js, when I tried it with both soundfonts "A320U.sf2" and "TimGM6mb.sf2", I got a slightly different problem that your issues #6, #7, and #8. When I send a "note off", sometimes (and it happens usually the first time), there is an attack with the same velocity as in the previous "note on" value; in other words, it creates a "spike" before the sound is cut off. Maybe I will take a look at what you have done in your codes after I finished adding the delay.
Bill said: