Rep Power: 0

Went to home depot today to buy some mdf for my subwoofer box, but it turns out that home depot doesn't even sell mdf, what a rip. I went to a local supply company that had 5/8" MDF (Medium Density Fiberboard) but not 3/4" which I was planning on using. Since the 5/8 is only 1/8" less thick should I just go with it or not? I'm planning on checking if Lowe's has any as well.

Supply List:

3/4" MDF for the box
1/2" MDF for the false wall
Self Tapping Wood Screws
Wood Glue
Some kind of sealer (silicon based maybe)
3M Spray Adhesive
Carpeting (hoping lowe's has a thin stretchy kind for me to use)

Would anyone suggest different? I'll be running 2 12" Fosgate P1s, so it needs to be sturdy, but not adamantium sturdy (not extremely sturdy, sorry, had to use the nerd humor there), so would the 5/8" be good enough?

 
Rep Power: 0

i think 5/8" would be fine assuming you will be pushing less than 800watts into those subs. now if you were to run a massive amp to those subwoofers, then id recommend 3/4" at least. but those arent high end subs and im sure you'll be juicing them 300watts a piece which will be fine.

btw, will this be ported or sealed?

 
Rep Power: 0

5/8" is fine for your setup with the P1s

 
Rep Power: 0

It will be sealed, decided on this because the manufacturer says they are "optimized for small, sealed enclosures" - just hope they still pump out the bump. :-), thanks for the suggestions

 
Rep Power: 0

It's strange that your home depot does not carry MDF. Mine has it in 1/2, 5/8 and 3/4 at around $20 a sheet. Stacks of it actually..

 
Rep Power: 786

go with 3/4, any thinner and you increase your risk of splitting the wood when you put your screws in.

 
Rep Power: 0

Yea I thought it was weird that my Home Depot didn't have any MDF either, in fact the stock guy had never even heard of it. I was planning on using self tapping (or self drilling, whatever you call them) wood screws for this, but all of the ones I find have that weird extremely bulky screw portion, almost like a built-on housing, like you would use for drywall. I'm not supposed to use those am I? Just regular wood screws that I can drill straight in, correct?

 
Rep Power: 0

DO NOT drill your screws directly into your MDF board! Either buy a small drill bit to make a pilot hole, or better yet, buy a countersink bit that will make a pilot hole and a recessed hole for the screw head to sink into. Without a pilot hole, I can almost promise you that you will split 5/8 or 3/4 atleast once. Not to mention, it's a PITA to do it without a pilot.

 
Rep Power: 0

Alright, thanks for the information, current plans are to use 3/4" MDF with 1" square braces in each place that 2 planes intersect , and 1.5" or 1.25" long screws to attach it all together - AFTER pre-drilling the holes. ;-)

 
Rep Power: 0

good call... i didn't take that into consideration... i was just figuring that 5/8" would be fine because my roommate has a pair of P1s and an 800 watt Kenwood amp, and they don't bump very hard... i was thinking in terms of structural rigidity rather than practicality...

 
Rep Power: 328

I, personally, wouldn't use 5/8" for anything but 8's, regardless of power. I really don't like it for the reason MH mentioned above, plus, with some subs, being as they move lots of air, 5/8, though minute, will flex a bit more.

As for the assembly, I'd recommend finding someone that has a biscuit joiner to biscuit the box if at all possible to keep from putting as many screws in it. Too many screws and you'll lose some rigidity. They create pockets in the wood by pushing it out of the way. Too many too close together will cause it to split. I'd also use tee nuts if at all possible when mounting the sub to the box as opposed to simply running screws into it.

 
Rep Power: 0

I'm powering mine with a 1200 Watt amp, not expecting crazy bump, but I hope I'm not just wasting my money. I will be using t nuts to mount the speakers, and I'll see if I can find a random family member with a biscuit joiner and maybe upgrade the wood glue I'm planning on using.

 
Rep Power: 607

They are right, it is a bitch putting the screws in the 5/8's. If you do go with 3/4, make sure you make a mark at 3/8's and draw a line which is the center so you put the screws in the center of the board.

Also, make sure you brace the inside of the box.

 
Rep Power: 312

wow, my box used 1/2 inch, looks like i need to rebuild...

 
Rep Power: 0

What material should I brace it with? Can I just use strips of 3/4" MDF to brace it?

 
Rep Power: 0

Or if I shouldn't brace it with strips of the 3/4" MDF what else should I brace with?

 
Rep Power: 0

3/4 will be fine with just screwing the screws in, pre drill will be better but not needed, countersink is good but if you dont wanna buy a bit just put a bigger bit in the drill and drill a tiny bit. I would go with 3/4 just on preference. Also get some like pillow stuffing to stuff into the sub box, not much in each but it kinda fools your subs into thinking there is more air space, sounds clean too.

ALSO SEAL THAT BITCH UP GOOD, like gallons of caulk lol, not really but enough to coat EVERY edge.

 
Rep Power: 0

Okay, for bracing the box, should I brace only the edges of the box? For instance like the way this guide (pdf) shows, or should I brace the interior walls against each other? - For instance like the box shown in the first picture in the first post here.

 
Rep Power: 328

I'd put a brace approximately every 8 inches of along the span of any right angles. Also, don't forget to recalculate your airspace after the braces. They're going to take up some of the airspace you'd have. You can also use L-brackets to brace, but the problem is, most of them are thin and aren't really very support minded, rather for keeping things square.