I don't! If you maliciously comply by playing something loudly which is so atonal and arrhythmic that you think it can't be defined as music the cop isn't just going to say "damn, outsmarted!" and trudge away sadly.

See my response to the sibling comment, but laws (like this) have been around for hundreds of years and we (mostly) manage to apply them despite inevitable ambiguity.

I'm happy enough to oppress people who use public spaces in inconsiderate ways. Society must enforce its norms, otherwise it's not a society. The norms might be immoral or unfair or imprecise, but it's what allows us to all exist together in some kind of sketchy (mostly) nonviolent (just about) cooperative equilibrium.