Still some sounds when PSG is muted in TT

[cornelisser]

This is and issue with the specific sound chips; SCC and FM

SCC -> The mixer register is not fully muting updates to the registers.
FM -> Even with volumes muted there still can be some sound produced. Even without a key-on trigger.

Avoiding any register updates when muted might solve the issue. More tests are needed.

[TastySnax12]

I ran into a similar issue when doing this:

Set mixer in favor of SCC
Turn PSG volume down in pattern editor
PSG should be very loud

Maybe something's underflowing.

[cornelisser]

Thanks. Seems that there is something wring with the max mixer settings too. Will look into that too/