hey just a quick question what would be the best way to build a strong sub box any advice would be appriciated thanks.

12-25mm MDF, PVA glue and screws. Figure out the volume you need for your sub/subs, and then take the measuring tape+paper+pencil out to the boot of your car and figure out the best spot to put it. Calculator may help with figuring out volume too.

Once you've done all that, you've got 2 choices. You can take it to mitre 10 with a sheet of paper listing all the sizes of wood you need, then take it home and assemble it, or you can go to a hardware joint and buy a sheet of MDF and cut it up yourself. What you do generally depends on what tools you have available. I've got plenty of power tools, but considering I paid bugger all last time I was at mitre 10 I may just pay them for my next box.

alright thanks for that mate how do you set up the ones that are set up in the conners of the boots of cars like lasers.

I'd say fibreglass would be the only way to do something complicated. I've never done a fibreglass box before, but I daresay MAXIMUM EXERTION will be in here at some point with a few tips.

you should be able to build a mdf box that fits nicely in the corner, just a matter of getting the measurements right, and maybe even doing some cardboard templates and that. fibreglass is more so for it you want curves and that, if ytou can design it all with straight edges, then mdf is perfect. the sub can be at any angle you want and that, like you dont need all 90 degree angles, just that the box won't have curves and that, still works fine though.

Bit of a pain doing angled cuts unless you have an adjustable table saw. I did mine on a table saw, and the angles are all sweet, but if I had my time again I would've done as many straight cuts as possible.

thanks for all the ideas so far guys keep em comin

If you want a moulded box in the corner and space is a concern fibreglass is the way to go, but if can handle a box some where in the boot go a square box.