Building a Subwoofer Box

[icor1031]

I posted this on another forum, but I expect you gentlemen will be able to give me tips too. Would you be so kind as to help?

I want to build a great sub box.

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Can you gents treat me like a complete idiot and let's get every thing I need to know, so I don't screw up? Please don't leave out the little things because it's my first sub build (I've build 7 speakers before this) that improve quality, unless they're quite complex.

Do I need screws, or is glue okay?
I'll need help calculating volume with braces, but I can ask that later.
How do I make my braces? Just cut a large circle out of a sheet of MDF, and put that inside? Does the size of the circle matter?
How do I make a double thick baffle?
Should I use feet? (It's sealed, btw.)
Should I flush mount?
And (not necessary I know) how do I put a cloth or grill over it? I want a professional look.

ANY THING ELSE that I should know.. i.e. do I roundover the edges? How much polyfil? Anything mates. I would appreciate.

[Cal Weldon]

What kind of tools do you have?
Saw, clamps, drill, router, screwgun, chop saw, brad nailer?
Use muti-ply plywood 3/4" or thicker
Glue two pieces together to make your baffle
Braces can be made similar to what you are saying but more elaborate to ensure rigidity.
Feet are optional depending on what you are placing the woofer.
Flush mounting is good.
Grill can be with male/female things, purpose made, or with magnets.
To determine the volume you need to know the Thiele/Small parameters. Volume is inside box measurement minus the braces and the volume the driver itself takes up.

[icor1031]

Router, table saw, chop saw, circular saw, jig saw, scroll saw, planer, files, bench sander, hand-held sander, probably some other stuff too.

Why multi ply plywood? The MDF I bought is not as good? :s

3.5Cu Ft PLUS whatever the braces / plate amp / drive use.

[sreten]

Hi,

Flush mounting and rounding edges is totally irrelevant for a subwoofer.
They are very easy compared to building a half decent loudspeaker.

Hardly any issues with a sealed sub, a good amp with boost options IMO.

How do you make a double thickness baffle ? doh, but simply not needed.

rgds, sreten.

[KRhirschkorn]

Too double the thickness of plywood or MDF use liquid Nails and laminate them together.I my self sue 2x4 as brace's. I also use 1 1/8 MDF or 1 1/4 floor decking. and i always spray the in side with rubberized undercoating. to deaden the in side of the cabinet. . On the corners I usr a 2 inch squair piece ripped down the center corner to corner. And use them in all 90 deg. corner's . My way of thinking is air flow and terbulance. I also dont use small port's I use 6 or 8 inch flared ports or a square port with paper tubes to flair both ends.

[454Casull]

Glue is a must, screws are a nice addition especially for panel alignment during the build (dry-fit, then drill pilot holes while clamped)

Bracing volume is easy to calculate.

There isn't much science to bracing yet.

A thicker front panel isn't necessary.

What flooring do you have? If you have hardwood, soft feet would be good. If carpet, spikes or nothing at all.

Flush-mounting is necessary for aesthetics only.

Any number of ways. Parts Express has accessories for grill mounting.

[Cal Weldon]

MDF will be fine if you've already bought it.
I like using cleats (inside corner blocks) instead of other methods of reinforcing the joints. I find it's the least time consuming and they make the alignment of the panels a non-issue. That's where the Brad nailer and a couple bar clamps come in handy.
What size is the driver?

EDIT: Typing while others posted.

[icor1031]

Can you show me some corner blocks, so I know how to make them?

It's 12".

Originally Posted by Cal Weldon

MDF will be fine if you've already bought it.
I like using cleats (inside corner blocks) instead of other methods of reinforcing the joints. I find it's the least time consuming and they make the alignment of the panels a non-issue. That's where the Brad nailer and a couple bar clamps come in handy.
What size is the driver?

EDIT: Typing while others posted.

[Cal Weldon]

First is cleats. You can make them out of just about anything. Here I used an old 2x4 and ripped it down. If you attach them to one side with the Brad nailer, go have lunch while the glue is drying, you can use them for the alignment of the other panels. Quick and easy. Second is braces. I only use stick bracing but I hear that shelf or panel bracing is better. The front to back ones are spaced to allow fitting of the drivers. The angled panel you see is a cabinet divider.

I will be away from the computer until tomorrow morning.