Thanks for all the information! It definitely seems to be original brick. The house dates back to 1919 although it was a complete rehab in 2018 down to lifting the roof and rearranging the layout. I think it has become fashionable to expose this brick in these rehabs but I question now if that is the best thing to do. Thanks again.

It's also fashionable to remove acoustical tile drop ceilings in office buildings and restaurants, for the "industrial" look. The result is intolerable levels of din because nothing is there to absorb sound, so it bounces around and echoes chaotically.

Fashion is seldom practical. The wise homeowner develops his or her own taste, and avoids "home improvement" television programs, websites, and magazines, which only exist to sell stuff for their advertisers.

Please come back and let us know what you've done, and how successful it was/is.

Sorry, OP, that they have rude neighbors! I don’t think they need an acoustical engineer, they may just need soundproof panels on that wall. Good luck!

That's an unfortunate problem and I doubt that it can be resolved without a lot of money and construction activity that will result in the wall being covered and built out. Even then, with that kind of nuisance, it's still likely to be something of an issue. I'm not trying to be discouraging, but I would hate to see them spend tons of money and still be annoyed by the residual noise. I also agree that it is not necessarily coming through the wall (or at least entirely): it could be traveling through the ceiling space. I once lived in a 2-story townhouse and the first time I went up in the attic to store something, I was shocked that I could see from one end of the building to the other. There was only chicken wire stapled in place to separate all the 6 attics in the building. Even if your daughter doesn't have an attic above, the noise could easily be traveling over the wall through the ceiling.

Buy ear plugs and ear buds. Pray they move. But the home of today is noisy , even without neighbors and brick.

When you raise the ceiling, add a lot of windows, hard flooring, and don't counteract that with enough soft furnishings, in rugs, window treatments, upholstery? You BET you have noise. Your own.!!

Exposing that brick? Simply saved furring the wall. the guy on stilts and a bunch of drywall and skim.

In their shoes, I might try some heavy duty, velvet type curtaining, like a theatre. There is a good chance the sound is travelling through the floors, some old homes had framing that connected a whole block of development. When we lived in a more commercial area, we could hear the music from the veterans hall 2 or 3 doors down, through the floor, esp at night as our bed was close to the floor. Our windows were also ancient, single pane, double hungs, they were about as effective against sound as a piece of paper. Another possibility is where a fireplace might be or any other place where the walls will be thinner. I don’t think the neighbours are bad, it is an unfortunate situation though. If it wasn’t music, it could be screaming kids, howling dogs, fighting adults, I personally prefer music. Have they invited them over to hear how much sound carries over? Maybe the neighbours could try soundproofing a music area.

If the guitar playing and sound system music enjoying isn't occurring after the hours during which people can mow lawns/build houses/destroy things with a sledge hammer/get out the leaf blower and chainsaw and start using them...You can call and make a noise complaint, but the police won't do anything about the racket because it's occurring during hours where noise is acceptable under municipal/city code.

There‘s little that can be done when a amplified guitar is playing next door. Not a good situation and just hope they get a “gig” on the other side of country and move. I would not hang anything on the wall unless it is fire rated and Used for acoustics. That’s all ugly and used in sound studios. And it sounds like the other side of the wall is furred out and dry walled, still not doing anything to quiet the music.

J Williams-

I, too, thought about the possibility that the sound could be traveling through the floor, but then recognized that the floors were likely decoupled if the brick wall separating the two townhomes ran all along the side. But maybe the floor on the noisy side is in physical contact with the wall and the vibrations come through that way. It's hard to say, other than that this is a complicated problem to have to deal with.

Ah yes, you are correct. I had forgotten that our last place only had plaster and lath separations.

I worked for a insulation company in Los Angeles (decades ago) and we used Insul-Quilt in many Sound/Movie studios and high rise buildings around mechanical rooms. They have some nice looking products now, if you really need to do something, You would have to glue a stick clip on the bricks and it might be hard getting it off.

https://www.insulquilt.com/