1x12 speaker cab - need to build fast and cheap

you have all you need. I'd suggest butt joints for the corners since you're short on time and lack the tools for dovetail; although you could do box joints using your table saw if you want to spend the time. You may want to use the 1x2 in the corners for reinforcement. Use plenty of glue and screws. Sand it and paint it when you're finished. If you can find some old window screen it may make a better grill cloth . . . or go without.

 

I would double up, but that's just me.
You can buy burlap at walmart for a couple bucks and it will work for grill cloth.
you can also buy dowel plugs to cover the screws at Ace Hardware for about 2 bucks per pack of 25.

 

3/8" ply is plenty for a speaker baffle. You'd want to go thicker with a 2x12" due to the necessary geometry of the cabinet / baffle. There's plenty of support in a 1x12".

I'd use real grille cloth or one of those cheap-o Radio Shack stamped steel grilles intended for autosound bass boxes.

 

IMO 3/8 is fine for 10" or smaller, but for a 12" I'd double up or reinforce it with pine 1x2. Without it you'll get some unpredictable and likely unwanted tone coloration/distortion

 

My favorite 1x12 cabinet

http://www.ax84.com/static/corecabinets/AX84_1x12_Cab_09.08.03.pdf

Designed to have the modal response of a 4x12. It is big, but works well with a wide range of speakers and can be built or open back (anything less then 70% coverage on the back is open back) closed or ported, if drop tuning is your thing.

Here are two I never seem to finish. I added enough on top to house a recessed handle and patch cables.
http://i35.photobucket.com/albums/d179/CeCeHall/DSCN0338reduced.jpg

 

I forgot to mention, I would use rabbit joints, not pure but joints. You can do them on your table saw. They give the joint a bit more area, so more strength.

 

I find butt joints with small dowels works really well.

Big glue joint along the butt and then 6 - 8 dowels provides mucho strength.

 

I have built exactly one speaker cabinet, but I read a lot!

I'll just tell you from my reading and little experience:
Most people say that with a closed back cab, "size matters", but not so much with an open back, so I'd build it open-backed and small. It'll be sturdier that way. A 15"x15"x12" box would be pretty sturdy even with 3/8" plywood, I reckon.

I recessed the front and rear baffles in my box instead of making them flush with the side edges, partly to help protect the speaker and partly to make it stronger by decreasing the distance between front and rear baffles.

I used .75"x.75" and 1x2's to mount the baffles and to reinforce the corners of the box. Probably much better than screwing into the ends of plywood, and that way you can bolt the front baffle on instead of gluing. Also, if you mount the reinforcements before assembling the sides, it'll help you to get the corners square.

 

That's a lot of box. Definitely the fast and cheap solution though. Plus you can pack all your other gear inside of it.

 

How did it sound?

My dad passed away when I was 20; if I had something like this of his I think I'd get a kick out of making it useful again and bringing it along on a gig.

 

In case you decide to slap something together,

this is a glimpse inside the cab I made, showing the reinforcement and recessed baffle:

 

NO NO NO! This will suck your sound up like a sponge. Believe it or not burlap at about $1.50 a yard works great as long as you lacquer it well. See my pics.

 

Awesome.

I built a makeshift 1x12 for an impromptu project once in about an hour or two. It looked like hell but did the job.

Here's another one I did that I spent a little more time on. This was my first, and so far only, attempt at box joints. Took a mighty strong belt sander to straighten it out

That grill cloth cost me a buck at a thrift store. It's actually an inside out couch cushion cover.

 

+1 on the burlap. I've done that a couple times, i'll post pics soon