Sub Box Building Question

D

derekwwww

Audioholic
I was wondering if it is possible to make a small sealed box without having to use any bracing? I built 2 small sealed boxes a few months ago. They are 14x14x14 and I used 3/4" MDF to make them. I didn't use any bracing but I probably should have or atleast doubled up the MDF. Would a small box like this work without bracing if a guy used 1" MDF, or even double 3/4" if need be. And if that can be done, my next question is if I used doubled up 3/4" could I make a sealed box that was about 18x18x36? Or if I doubled up the MDF and used just a couple 2x4 braces inside would that work? And if all of this sounds bad can someone refer me to a place that kinda teaches how to properly brace boxes, thanks!
 
R

RandyStacyE

Audiophyte
As far as sealing the box I would check out:
www.sanitred.com

This coating is tough as a truck tire, permanently flexible, and life time warranted. It may not add structural integrity to the box but is will turn the box into an aquarium (it is that good of a seal). I personally don’t have a deep education regarding Hi Fi audio or whatever, but this stuff works better than you can imagine.

I have used these products many times and after coating your box you can literally drive over the box with a truck and the box will still be sealed (collapsed sure – still sealed YES).

I imagine that bracing is primarily to ensure that the box will forever remain firm and rigid. In other words it won’t wobble.
 
annunaki

annunaki

Moderator
You are willing to laminate the entire enclosure with a second layer of MDF yet you are not willing to use a simple bracing system???? :confused: I do not understand the problem with using some small 3/4" MDF right angle triangles. If well placed, they can brace the enclosure very well. :) Is your sub that sensitive to volume changes? I highly doubt it. As far as sealing the enclosure, if it is well put together nothing else is really needed. Let me know if you have more questions. PM me if you would like. :)

There is not really a need to go as extreme as I did. I just did it because I could.:D See here: http://forums.audioholics.com/forums/showthread.php?t=15445
 
WmAx

WmAx

Audioholic Samurai
derekwwww said:
I was wondering if it is possible to make a small sealed box without having to use any bracing? I built 2 small sealed boxes a few months ago. They are 14x14x14 and I used 3/4" MDF to make them. I didn't use any bracing but I probably should have or atleast doubled up the MDF. Would a small box like this work without bracing if a guy used 1" MDF, or even double 3/4" if need be. And if that can be done, my next question is if I used doubled up 3/4" could I make a sealed box that was about 18x18x36? Or if I doubled up the MDF and used just a couple 2x4 braces inside would that work? And if all of this sounds bad can someone refer me to a place that kinda teaches how to properly brace boxes, thanks!
You should have no issues without bracing in the box construction that you described. The panel resonances will not be within the bandwidth that you are using the speaker[this is a subwoofer], therefor they do not matter. The only issue that normally exists with a subwoofer wall cabinet is flex, which if it is severe enough flex[think of 1/4" plywood one 3'x3' panels], it would cause inverse sound pressure on the exterior, thus cancelling some of the output. But that is an extreme example, and the panels of this thickness and surface area would probably also have resonances within the used bandwidth of the subwoofer. But who would build a cabinet like this? It's just an extreme example.

-Chris
 

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