hey guys,

this isn't really a "soundproofing" question, but more a sound reduction question.

Behind my living room is an estimated 7 by 4 entrance where the door to my apartment. It doesn't have its own door to the rest of the apartment.

The rear wall of it (which is 129 inches long, 110 inches high) is shared with a neighbor behind me who is older and retired. She told me that she often hears the bass of my music and it's annoying. I played some music with some good bass, stood in my entrance way, and of course, the bass there is very loud compared to the rest of the apartment due to its shape and size.

So I'm wondering, what's a good, cheap way to reduce the vibrations on that wall? My floors are hardwood, but concrete underneath. I'm considering putting down a carpet in the entrance way to reduce vibration there. But otherwise, any good cheap ideas? If course I'd like to double the wall up with some insulation and QuietRock, but for a rental, that might be going too far