subs sharing airspace in a ported enclosure?

[ralimore]

In every single box I have built in the past each sub has had its own airspace sealed off from other subs by an internal wall. I admit I am way out of date on enclosure theory. That being said, I have seen and heard several nice systems lately and some have subs sharing airspace in the box. Now comes the questions part.

When 2 subs share the same air(for example a 6cu box with 2 subs in it) does each sub act like its in 1/2 the airspace or does it act like one sub in the whole airspace?

If 2 subs share an airspace do they fight against each other or act like one big sub?

What are the cons/pros to open chambers as opposed to each sub in its own?

I am building a box/wall in an 08 nissan frontier kingcab and am still playing with design as I try to maximize airspace and not have to move my front seats up. If I build it with seperate chambers sealed off from each other inside the box It will change how I brace for flex using the center as a main brace. If I leave the inside open (except for bracing) then how do I figure volume to correctly port? 1/2 the airspace per sub?

I really dont want to do as I have in the past with boxes and keep pulling them out and remaking them to get what I want. This needs to be a one time get it right. Retuning will not be a problem as I plan to either make a drop in or use aeros, so I just need to get the enclosure built right first.

Planning on 2 RE sx 18s. I guess what I really need to know is seperate or shared airspace in the 12cu enclosure.

Edited May 18, 2012 by ralimore

[fecupe2001]

The expression you are looking for is "common chamber" , you have always used seperated chamber, i´ve tested this myself a few times, and i LOVE how performs a common chambered box, also, you save some good internal space of the box by doing this.

Common chamber FTW hehe

[Akslowroller]

Well I'm no pro however every box I build where the subs share air space I take recommended ported box size and multiply it by number of subs. The three boxes I've built have turned out well. Could have been dumb luck. As far as porting I also went with manufacturers recommendations.

[Joe X]

You will definitely save space with a common chamber.

[ralimore]

So, does each sub "see" half of the airspace or do they act like there in the box by themselves.

Will each sub see 6 or 12 cubes?

[iamamp3pimp]

So, does each sub "see" half of the airspace or do they act like there in the box by themselves.

Will each sub see 6 or 12 cubes?

6

good luck with the build.

[ralimore]

Thats what I was assuming but since this place exists I wanted to get verification. Thanks! Next step, pull all the trim and seats out of the back and get actual measurements. That and whatever I decide to use to deaden the back of the cab with..

[EdgarG0721]

Each sub will see 3 ft not 6

[ralimore]

Split airspace...got it

Edited May 18, 2012 by ralimore

[EdgarG0721]

didn't see the 12 ft tought it was 6 but yeah they split the airspace

Edited May 18, 2012 by EdgarG0721