Im looking at making new boxes for my car and the idea of a plexi box popped into my head, i was wondering if i could get away with mounting the face of the sub to a sheet of 3/4 inch plexi glass.

JBL GTO 12" 300 RMS

Only one sub on each sheet (subs are separated)

 

should work just fine.
post some pics when your done.

 

well my friend, i work in a glass shop and i have attempted this but not with plexi... with MR10 lexan, and honestly if your going for shock and wow factor and not sound quality its worth it... but not for quality... it takes alot of reinforcment to stop it from resonationg and flexing, a well built fiberglass can look better
UNLESS you went with acrylic tubes and solid front like digital designs did