longplayer
A much tidier solution - and equally effective - is to install dedicated 20A lines, but derate the wire to 10AWG or better. That will let you keep the 20A breakers and use 20A receptacles, and will also meet code.
If at all possible, install 30A dedicated lines for your audio system.Installing 30A lines creates quite a nuisance because to do it and also be compliant with code means you'll need to install 30A receptacles. That means you'll need to either put new plugs on all of your components to fit the 30A receptacles, or you'll need to make 15A/20A to 30A adapters for each component, which is also a nuisance.
A much tidier solution - and equally effective - is to install dedicated 20A lines, but derate the wire to 10AWG or better. That will let you keep the 20A breakers and use 20A receptacles, and will also meet code.