I will hopefully be making a box for a ten inch sub later in the summer, (Way behind schedule) . I was figuring it would be MDF and or Fibreglass. Are there any weight saving tips or materials that one of you experts might reccommend? Thanks, Bob.

 

Fiberglass is pretty light. There is also lighter MDF called Trupan or various other things, it's about twice as much, but 40% lighter I think.

 

Birch plywood is quite a bit light I believe, but also quite a bit more expensive.