[Kevin]

Invite the neighbor!

Seriously though you might just make an attempt to discuss the situation with the neighbor, let them know before you have a party so maybe they can make plans.

They probably didn't call you a second time because people generally don't like to directly confront people about issues. In this guy's case I think that is evident since he called your folks before talking to you.

You just need to find out exactly what would be defined as too loud. At least then you'll have a starting point for your party control.

Good luck!