Thanks, that's really helpful. For some reason I'd assumed that the code on the EPE site was just for the electronic ignition. I'm intending to use your code with the glide/hammer-on function, but I wanted to see how it differed from the original so that I can better understand how the coding works. The function that I'd also like to fathom out is how to get a note to sustain indefinitely until a new note is plucked. That way I can use envelopes that have a much longer duration than the guitar's natural string vibration.