I'm looking to building a custom box that would take up the entire hatch/spare tire area. I was considering 2 subs, and this question wouldn't really apply as much, but were i to go with 3 subs, i was wondering if you needed to isolate the subs in the box. By that i mean that each sub has it's own individual little box with it's alotted airspace. This would make a 3 sub setup more of a PITA because it would be troublesome to ensure that all 3 subs had the same box volume.

I've heard both ways, one says that each sub should have it's own box because 2 subs my "confuse" eachother on how much air they have to work with and this could damage the sub by bottoming it out, and another school of thought that says that it doesn't matter if they're using the same airspace.

My current box that i bought at an audio store has each sub isolated, but it's a big rectangle so it's easy to ensure they both have the same air space. I've heard that they only make them that way because of bracing (heard a story about a box "blowing up" cuz it wasn't braced... bad shit). Can anyone clear this up?

the only time you would need to isolate subs is if they are running different signals (for example, if one was hooked up to the right channel and the other was hooked up to the left , or if you were using two different amps on the subs). it is, however, a good idea to run a few braces inside the enclosure, expecially considering that it will be quite larger. i would do two vertical braces that stretch from the top of the box (the plane where the subs are mounted) to the bottom of the box (the parallel lower plane of the box).

to help you get started, the diminsions of a rectangular box that fits PERFECTLY into the hatch are as follows: 40" wide, x either 20" or 24" deep (cant remember, make a cardboard template to help guide you, im nearly positive its 20" though), x however tall you need it (make sure to account for the excursion of the subs when calculating height).

if you build the largest possible rectangular box that can fit in the trunk, you will net around 4 cubit feet, or about 1.15 cubic feet per sub(assuming 3 subs)after accounting for displacement of the subs mechanical structure and the braces.

after sliding the box into place, you can construct a cardboard template as a pattern for a "cover" made out of 1/4"-1/2" mdf so that the box seems to extend to the walls of the trunk. thats the way i did it in my second install, and it only took about 10 total hours to design, construct, and upholster the whole thing.

whao, i ranted there, sorry bout that, lol. ill call my dad tomorrow and see if he can get the exact dimensions for the box from my old one in his garage.

dont listen to him, he is lying through his teeth...

just cut a hole in a cardboard box and ull be good...

hahahahahahahahahaha

just kidden, always listen to him, he is right 99.99999% of the time

thanks. that was an extremely informative answer. and it makes my life a little easier :)

Also, if your planning on building a ported or bandpass box, then you DEFINATLY want to isolate the subs for airspace reasons, but if your building a sealed box then it doesnt matter, I always isolate each subwoofer in the subwoofer boxes i make regardless of what type of box im building, just in case one of them blows (which isnt an uncommon occurrence for me), then I can still run one of them safely and disconnect the other.

Isolate them. Little bit of extra work but you want to do it right it right the first time. All the people I have talked to about this said that I should isolate mine when I did my box.