I don't know that people are deliberately rude and ugly. It's hard to remember that it isn't just "you" but that things add up. The girl with the bass may not know just how loud it is since she's in there with it and it may sound "normal" to her. She may be hard of hearing (you think? LOL) or distracted or whatever. I had a friend that had to have the TV, stereo and whatever else "on" for comfort. If the apartment building is new and "cheap" that doesn't make the soundproofing very good?

One of my stepsons is 7 feet 5 inches tall and daily gets a zillion people asking how the weather is up there or how tall are you, etc. and no one person thinks about the cumulative effects of a day's worth of people asking rude, personal questions. People can only think (even you and me) most often about what's right in front of us now. You have a "giant" in front of you, you want to know about the giant; children and adults that are not shy and didn't learn better manners when they were children will ask. My son actually had to report a bank teller to her boss because, instead of doing his transaction and helping him, the first words out of her mouth were, "How tall are you?" with that amazed look like he's part of a circus.

Doesn't help knowing it's not you or even not the girl with her cheap bass turned up too high.

Is she around your age or anything? I'd be inclined to try a bit of personal humor; make some chocolate chip cookies or something and take them down and "beg" her to turn down the bass or become good enough friends with her so she "remembers" you in some way and thinks of you and her volume knob together but not in a "she's a nag, I'll show her!" way that will only make her keep annoying you because you "annoyed" her and, in her mind, are trying to control her (like the apartment itself and having to live in such a place already feels like it does).

Ocean, the piano player reminds me of mine when I was in apartments; garden apartments one up, one down and I was on the ground floor. I'd be awakened lots of nights by the couple above me (boyfriend and girlfriend, she didn't live there) making love at like 2:00-3:00 a.m. BUT, that wasn't the problem, immediately after, he'd get up and play his piano!!!! My boyfriend/now husband had the apartment across the parking lot and I usually was with him but would stay in my own apartment when he was away on rare business trips. So, I didn't do anything about it but my fantasy was going up there in my flannel nightgown, right out of my bed, knocking on the door and when he answered, saying, "I don't mind the sex in the middle of the night and your squeaking bed waking me but the piano playing afterwards has to got to go!" :-) Can you imagine their embarrassment? LOL