Hey Pall, bored again?
Fantastic job, I like how the Start and Stop functions set in with a sweep. Also Fast Forward and Rewind are so cute, exactly how those devices used to work. Well done!
Suggestions for improvement: I think the SVF is not the best choice for the tone control. Perhaps a cheap 1-pole LP would be more like it? Also the speaker would probably not go below 200 Hz nor above 5 kHz, so maybe one could include a bandpass as a property at the end of the signal chain? And maybe a mono option? I could provide the components but I am hesitant to directly integrate them because I do not want to spoil your beautiful design.
Oh, and please, please add a button to reset the counter!