Subwoofer question

[mikenehrkorn]

I was going to construct a box for my sub and I have some 1/2" plywood available -- is that sufficient thickness or do I really need 3/4"? And is there any difference between using plywood vs. MDF? Or is HDPE an even better choice of materials?

I also read somewhere that you should use a double layer of wood on the side that the sub is mounted on -- does that make a difference?

[David Analog]

1/2" ply or anything else isn't going to be thick enough, and I am assuming you are running a 10 or 12" sub. So 3/4" is generally required. A 1" baffle is often used on 50 Lb. subs, but not necessary for the norm.
Plywood, like cabinet-grade void-free Baltic Birch is good. Flooring grade is not.
Starboard is out since it is close to impossible to glue and seal. HDPE can be glued but I would still avoid it because it is harder to keep a seal long term.
MDF is water-soluable. Not good in a boat. It can be successfully used if the execution is near perfect and you seal it with a coating. Polyester resin is good. Epoxy resin is better. True polyurethane bed liner is good, but not the faux paint. You will wick water through any protective coating, so you have to elevate the enclosure off the sole a bit to provide for drainage and evaporation.
Solvent-based wood products are better, such as Medex, MDO, and Extira. You should still coat any of these.
The worst thing to use is a pre-fabbed MDF automotive box covered in trunk liner carpet. Those don't usually last a full season before the seams begin to fail, although the carpet covering may conceal the damage for several more seasons.
That's the short list.

[viking]

How about some other good tips such as liquid nail and/or silicone to seal the seams? Or what are the best screws to use? Re-enforcement points, angles, ect.....
From someone who has done it for many years you've got to have figured out some tricks of the trade? Do share!!

[MLA]

I agree with a lot of Davids approach. For heavy subs, a 1" baffle is a good idea, or even better, add a cradle to support the motor. With typical 10's and 12" nothing extra really needed.

Im a ply guy, dont do MDF or other. More personal preference on how it works. For me, glue bonds the joints, caulk seals the joint and 2-part encapsulates the enclosure. I dont rely on one step to the others. I like the bedliner as final for cosmetic only.

[New Guy]

Birch ply and biscuit jointer and glue.

[wolfeman131]

you enjoy using that biscuit joiner, don't ya?

[New Guy]

yup boys and their toys.