MathDoku does that and I hate it, because sometimes cookies expire and it plays loud music in the middle of the night when I start it. What's wrong with
I think most people would agree your solution is preferable, but the spirit of this subthread was "what's the smallest change that would improve things" rather than "how could it be redesigned from scratch?"
I would also argue the MathDoku problem is different. That sounds like a mode confusion type issue, where the user expects a certain level of automation but it has been disabled by the system without adequate feedback.
What's wrong with "start with sound" and "start without sound"? That's a guaranteed single click, whereas with a checkbox you need either one or two clicks.
