Now listen to it played through MiST: the "vibrato" effect disappears completely and the notes played sound quite different.
Previously another user (@Higgy69) suggested this:
Just to let you know I came across someone who has implemented Channel Modulation in Minimig.
It may help you save some effort/work.
I mentioned this on the MiST forum ( Atari-Forum) and asked if someone could build a new Core with this new Audio Engine added. Thinking about it, I should have mentioned it first to you as your work is the main goto for Amiga Minimig for MiST owners ;)
Since Atari-forums' down at the moment, if it's any help I think higgy's post referred to this: http://www.minimig.net/viewtopic.php?f=7&t=633&start=10 - madeho did indeed implement modulation, and his source is there for anyone who's interested - but there were problems with it which would need fixing - it didn't seem to go any further.