my question is im trying to make a box for 2 18" btls dimentions are 49"L x 24"T x 27"D here are some rough sketches from paint

how should i go about bracing it i know that i need to(or do i?) since im planing on running them on 2 SAZ-3000D

and i will doublebaffle the top where the speakers will be mounted

would simply corner bracing like in this pic be enuff and also placing a small block of mdf on 1 or both sides of the port to support the middle of the box

Edited April 21, 200817 yr by dsgfierce1

You want to put braces perpendicular to the longest unsupported sections of the enclosure, those are the parts that will need bracing the most.

I assume this isn't for a pure competition setup? If you're chasing every last tenth of a dB, extensive bracing might not be as good of an idea. But if you're only casually competing, it shouldn't be an issue.

You want to put braces perpendicular to the longest unsupported sections of the enclosure, those are the parts that will need bracing the most.

I assume this isn't for a pure competition setup? If you're chasing every last tenth of a dB, extensive bracing might not be as good of an idea. But if you're only casually competing, it shouldn't be an issue.

no just going for a very loud daily and just wanted to make sure i had a solid box so that it wont destroy it self with the btls lol i was wondering also i saw a post but i cant seem to find it again talking about some kind of metal rod or something like that, that could be used for bracing and bought at home depot or would it be better to use wood to brace it.

You want to put braces perpendicular to the longest unsupported sections of the enclosure, those are the parts that will need bracing the most.

I assume this isn't for a pure competition setup? If you're chasing every last tenth of a dB, extensive bracing might not be as good of an idea. But if you're only casually competing, it shouldn't be an issue.

no just going for a very loud daily and just wanted to make sure i had a solid box so that it wont destroy it self with the btls lol i was wondering also i saw a post but i cant seem to find it again talking about some kind of metal rod or something like that, that could be used for bracing and bought at home depot or would it be better to use wood to brace it.

or would the port braced on both sides like in the pic without the corner braces be enuff since it is right in the middle and would add support to both of the longest pieces of mdf right in the middle of them and also provide support to the top where the speakers will be mounted?

Edited April 21, 200817 yr by dsgfierce1

one more thing just to get peoples opinion weather or not the box needs bracing. I have the box 90% compleat all i have to do is cut out the holes for the speakers and glue, screw, nail, and siclicone the bottom of the box its pretty much as compleat as it is in the sketches except for the speaker holes.The reason i dont have pics of the actual box is the cam i have sucks a big one and the pics are not worth crap.I had my girl stand on both sides of the box as well as the top where the port is on each side where the speaker would be mounted and bounce on it a little bit, As well as both of the long sides right in the middle where the port is she is about 120lbs and i also did the same thing im around 240lbs. both times i saw pretty much no flex what so ever in the mdf from any angle.i added the blocks of mdf on both sides of the port to support the middle. so im sure that once the bottom is secured on that will add event more support to the side that allready had no flex with me standing and bouncing on it. does this sound like its strong enuff?

haha, you wont be able to flex it, but pressure inside the box can.

i got a vid on youtube of this one sub i had bolted down to my trunk floor everywhere. You couldnt move that box for nothing... but when the lows dropped, the box was trying to pull the trunk floor up with it shuttering like crazy.

The rod is called all-thread and you would want 3\4".

I would run L brackets on the corners that need it, space every 12-16"

All thread from one side to the other, nuts on inside and outside, washers too.

2x4s on inside or outside depending on where u got room at if necessary.

haha, you wont be able to flex it, but pressure inside the box can.

i got a vid on youtube of this one sub i had bolted down to my trunk floor everywhere. You couldnt move that box for nothing... but when the lows dropped, the box was trying to pull the trunk floor up with it shuttering like crazy.

The rod is called all-thread and you would want 3\4".

I would run L brackets on the corners that need it, space every 12-16"

All thread from one side to the other, nuts on inside and outside, washers too.

2x4s on inside or outside depending on where u got room at if necessary.

well i desided to fiberglass the whole inside of the box and add some 2x2 woodbracing on each side of the box right where the subs will mount and also add 2 pieces of all thread on each side of the port i think that will be plenty enuff bracing if this box fails on me after all that bracing glue fiber glass allthread screws and nails and silicone then i quit lol

so far this is what it will look like when im done this is my bracing plan square dots are 2x2 wood and the round dots are the all thread + the whole box will be fiberglassed look sturdy enuff? lol

Fiberglass resin has no strength, and even fiberglass itself needs curvature to build strength. Bracing is a much better solution

Fiberglass resin has no strength, and even fiberglass itself needs curvature to build strength. Bracing is a much better solution

oh i know thats why im using fiberglass cloth not just the rez

Edited April 22, 200817 yr by dsgfierce1

i got the box finished today and tested it out with an old rockford punchZ 15" i had laying around and it sounds f'n awsome was shaking the pics on the wall in the house i cant wate to hear how the fi btl's will sound