We have been staying at Arena Suites for over 15 years now and have never heard music from town, only occasionally a wedding at Brisas del Mar next door.

I am sorry you are going through that. Can't be any useful purpose for loud noise at that time of morning. It used to be the case occasionally for me in Las Mesas when the fairs would set up in the basin near La Noria/fishing lagoon on the side of the entrance to Cinco de Mayo. Not sure what happened but the carnivals or fairs that have set up down below have been mostly quiet after 10 pm this year.

Maybe there is a local political way to deal with the problem?

The "La Noria/fishing lagoon" we call "Laguna Las Salinas" as well as the entire watershed area surrounding it. The current municipal administration is working hard to restore some semblance of law & order including getting the noise under control. They're making headway, but last night was a reminder that we still have a few things to work out. There is no enclosed venue for events of this kind in Zihuatanejo. No enclosed sports stadium or arena. The zócalo and the lands around Las Salinas are the only places we have that are easily accessible, so they are still used for these late and loud events.

Anyone else bothered by the horrible loud music coming across the bay last night? I swear it lasted until at least 5 or 6 this morning.

It was from the zócalo. Not sure what was being celebrated, but I tried not to tap my toes in my sleep.

Maybe there is a local political way to deal with the problem?