Based on what you said (about them being neighborly), I don’t think you need to resort to noise ordinances - which is like saying - we’re ratting you out or you’re breaking the law.
How about - hey, as we are share walls, for whatever reason we now hear your music, and it keeps us up.
Would you mind turning it down a notch?
99% of people would be like - wish you told us sooner - sorry about that. And will turn it down a bit.