This worked for a friend of mine with a bass-
heavy rap music lover for a neighbor.

My friend lived in a apartment building that had
a common utility room where all the circuit breaker
panels were. When the offending neighbor started
to crank the bass and become obnoxious, he would
sneak to the panel, and trip the breaker in the neighbor's
breaker panel on a prominent heavy bass note.
He would then sneak around the building and back to his
apartment, unseen.

After playing this cat and mouse game for a few weeks,
"bass-man" figured out his stereo was tripping the breaker
and learned how far he could turn it up before it crapped out.