My 2 cents.
You'll probably never have the volume turned up loud enough to reach the circuit's max ampacity.
You'd blow your eardrums first.

I would check all the connections at the receptacle and breaker, to make sure they are tight. They tend to loosen with use, due to the circuits heating and cooling cycles.
If for any reason you do have to upgrade that circuit, you have to change everything; the wire must be 12AWG for a 20 Amp circuit, along with a 20 AMP receptacle. So, you can't just install a 20 Amp breaker.
Rick