Pipp makes very little noise. Her flock calls can be a bit loud, but I think it's because our house is big, which is good for keeping us cool in summer, but not good for noise. That's why Pedro our eclectus got rehomed, because the noise was too much and since I was 10 at the time, I'd much rather play video games then interact with the bird(I regret it...), and neither did anyone else give much attention, so now he lives with a friend.
On a scale of 1-10, I'd say pipp is a 3. Bit loud, but not enough that someone will file a noise complaint. Unless they want zero noise. In which that case they probably shouldn't be living in an apartment.
Pippen's little "Wee-wee" cannot possibly bother someone. She sometimes goes "WEEEE" when she really wants me, but it's not that loud, and it happens occasionally, not constantly.