what kind of wood

[bonesninja 5,000+ posts]

looks like to keep the 10" and the 15" you would need to go 36.375 wide, giving about .100 displace per sub this would give you 2.1 net after subs.

so 10'' x 36 3/8" x 15" just mark off the halfway mark and do your divider for seperate chambers

 

[hempy 10+ year member]

Considering how much cabinet grade (let alone marine grade ply) costs, you'll probably save money going the 30 miles to get the mdf.

 

[jester king 10+ year member]

I'm inverting the subs, so I dont need to wory about displacement, and I'll be using 5/8 inch wood, and as long as the box is around 1 cube per chamber then its all good

 

[bonesninja 5,000+ posts]

ok then right around 10" x 32" x 15" this will put you real close just mark off halfway and put your divider and your good