Hi everybody, this is my first post.

Moderator, if it is not allowed to post in two areas, please delete this post

I am installing four MMC650's as a home theater system on my boat. They will be installed into factory cutouts in the "ceiling". The area where the cutouts are is solid plywood pieces, about 2'x2' in size for each cutout. However, everything else is acoustically open because the "celing" is just single layer vinyl mounted on large frames; it is called headliner panels in boating I believe.

Head unit is a Harman Kardon 335.

How should I attemp to install the speakers to control this open baffle situation?

Wouldn't they create an "acoustical short" if I install them just as is because the front and back of the speaker membrane would be acoustically coupled (the ends of the 2'x2' panels are open)?

Would I have to create an enclosure for each speaker to isolate them (which would be very difficult to do because I would have to dismantle most of the headliner panels)?

Or should I try to wrap and stuff some acoustic material around each of the install panels to create some sort of separation and leave it by that?

Space from the headliner panels to actual fiberglass ceiling of the boat is about 4" and, to make things even more difficult, it is curved (as most things are on a boat).

Thank you for your help ,
David