[quote
Can someone explain this joke? I don't get it.
[/quote]
Well, the neighbor, obviously a devotee of chamber music performed on period instruments reproduced via a flea-watt system, appears to be dismayed by what he assumes is the woman-next-door's new thrash metal system.
What he fails to realize is that she is merely a Facebook Marketplace seller taking delivery of the last bargain she found on Craig's List before marking it up 300% and reselling it.