I have a townhouse that's about 18 feet wide, so all the rooms are pretty much the full width of the building. The construction of the party walls is concrete block with furring strips and drywall on either side. From what I can tell there's about 1/2" between the back of the drywall and the front of the concrete block, and there's no insulation in between. The floor joists run parallel to the party wall and they don't actually touch it, there's maybe half an inch of space between the last joist and the wall.
The two townhouses on either side of me are mirror images of each other. The only difference is that one of them is about 2 feet higher than mine, because the row of houses is on a hill. I hear sound from the one that's on the same level, but not the one that's a little higher - that kind of puzzles me because I wouldn't think there would be much difference in construction between them, so if I can hear kitchen cabinets closing in one then I should be able to hear it in the other, right? Maybe the residents in the higher house are just quieter?
On the side that I get noise issues from, the layout is the following: the back approx. 1/3 of the house is my bedroom on the second floor and the kitchen on the first floor. The layout in the bedroom is kind of limited, so my bed is against the shared wall. The other 2/3s of the house is a stairwell - the first-to-second floor stairwell is open to the living room area, and the first-to-basement stairwell is walled off.
It is fairly quiet (I can't hear conversations at a normal level for instance) but there are some things I do hear: small clink/thud noises which come from the direction of their kitchen so I'm assuming they're cabinet doors being closed, some other kinds of thud noises which I think are doors elsewhere being closed, their shower when it is first turned on (it's right up against the wall pretty much in the middle of the open stair area, the long wall of the tub is parallel to the party wall), music when they have it turned up very loud (but not loud enough on my end to identify it), very loud conversations/yelling (again not understandable but I can hear the vague sound of voices).
I know some things there can't be done anything about - bass from a loud stereo or slamming doors such that they physically shake the whole building. I'm wondering if there is anything that can be reasonably done about some of the other stuff, though, or if any soundproofing attempts will either not block that type of noise or be too complicated to do (not up for reconstructing half my house). The main things that concern me are the various 'thud' noises and the music, specifically in my bedroom. Volume-wise the sound of these things can be drowned out by my white noise machine on its lowest setting, but some of them I think you can feel half as much as hear.
The wall in my bedroom that adjoins the problem house is 100% solid - there are no outlets or openings of any kind in it. So I figure it will not be too hard to do something like slap another layer of drywall with some green glue up. The stairwell wall is more problematic because it has the stairs there - I obviously can't move the stairs or anything and while I could probably put up another layer of drywall, it is tricky with the trim for the stairs and it'll be awkward in general because I'll have to get scaffolding and such to get up to the open 2nd floor area. So I don't want to do that unless it's 100% certain that it's going to be useful.
One thing that I learned this weekend, when they had some music with loud bass going on late at night and I couldn't sleep, was that their speakers are apparently in their basement, on the opposite wall from my house, yet I could hear it / feel it clearly in my bedroom 2 floors away. So obviously the sound goes up the wall rather than horizontally through it.
Would there be any benefit of applying green glue + drywall to the bedroom wall only? Or even taking off the drywall that's there and putting up clips? Adding soundproofing to other areas of the bedroom? Or would the sound likely just go around / not get blocked by these things? Would it ever be worth the expense to try to soundproof the stairwell wall?
It's not a bad enough problem that I want to spend more than a few hundred bucks on it, I am just trying to get a feel as to whether there would be a potential benefit to this at all. Green glue on the one bedroom wall definitely strikes me as the easiest solution.