(Sorry about the earlier mis-post. Blush, blush...)
Susan, I don't find quite the cohesion in this sonnet as in your previous two. Perhaps those two are damn hard acts to follow.
Or perhaps it's because the turn doesn't come in the expected place, although that typically doesn't bother me, so maybe not. But that odd placement of the volta does definitely underscore for me the fact that I'm expecting a different kind of argumentative equilibrium and symmetry between what comes before the turn and what comes after. I can definitely see the contrast between vocal silence and eloquent musical expression, but you're leaving the reader to make the two counterbalance each other with less guidance than you usually provide.
Anyway, this sonnet doesn't move me quite as effectively as the previous two did. (Perhaps the effusive turn is just a touch too telly about the narrator's being swept away by the musical memory, and some part of me is resisting that? Or maybe it's just that "Then," plus the past-tense verbs in that line, don't form a sturdy enough lynchpin for the volta to swing satisfactorily into the present, which is where I think a reminiscence needs to end.)
Not sure if that reaction is helpful to know, but I offer it in case it is.