I'm looking into shaving weight on my car. Now I expect a fiberglass sub box to be lighter than a full wood box but does anybody know how much? Minimal or a lot?

 

use 3/4" birch. it doesn't weigh all that much, and will more than likely cost less then getting a fiberglass enclosure made for you.

 

Agreed. Also wood does not resonate, glass/plastics/etc do.

 

thank you

 

Use solid birch, not birch plywood..Having worked in a lumberyard that sold LOTS of birch plywood, and now working in a hardware store that sells smaller pieces of birch wood and plywood, and also having made enclosures out of both AC and birch plywood, as well as MDF, I can say with utmost confidence that the birch plywood still has all the acoustical downsides of using conventional plywood (slate center core, plus weak glue at certain points = resonance and buzzing). If you want solid wood thats strong, light, and non-resonant, and if solid birch is harder to come by in your area, you can substitute poplar.