Betty Said:

How to write apology letter to your neighbor?

We Answered:

Are you planning to give this to them the next day ? ...lol

I would let them know in advance that you will be having a party. Tell them that you will do your best not to disturb them but to feel free to call if the music is too loud.

This will A) encourage them to call you instead of the cops if they have a problem and B) they will feel that you were very considerate for offering and will probably be a lot more tolerant than they otherwise would have been and C) they can plan their evening around it so they're not trying to hold a book club meeting or something quiet that night and your advanced notice gave them the opportunity to make other plans.