subs hitting wierd

Ok as far as phasing being the problem it is not about the subs being out of phase with the rest of the system..which is what that switch on the deck is for..it is the subs being out of phase with each other.

However you seem to be pretty sure that they are wired correctly.

So it is a problem with the box..I agree with xtremeimage there. But I personally have built plenty of ported boxes where mulitple woofers share the same airspace..there is NO reason this won't work...If it's built right.

Any ported box built improperly will react unpredictibly, not give the best sound..and can lower the power handling of the subs causing them to blow prematurly.

Now regardless of the subs being in the same space..or divided you need to take everything into account when building a vented box.  The correct airspace..the correct port volume...well sealed and braced where needed. Otherwise expect problems like this or worse.

There are some good programs out there that you can load in the T/S parameters of your subs..and it will instantly give you all the proper specs and if like my program gives you a cut sheet as well. You tell the program the type of enclosure (sealed, ported, bandpass, iso..anything basically). It even displays a graph predicting it's F3, output..power handling etc..really nice.

http://www.carstereo.com/help/Articles.cfm?id=17

If you go here you can use this "basic" calulator for a ported enclosure. You will need to enter some parameters which you should have or must get from the speaker manufacturer. You can determine the TS parameters yourself with some equipment but it's time consuming and not really nessecary for a typical install.

Now if you are going to divide each chamber just enter "1"  and build the other 2 chambers/ports indentical.

If you wish to share the airspace enter "3"  and it will give you the specs.

Good Luck

well it is a prefab box and i think there is something wrong with it  but anyways i need box for 4 of them now but what kind of box building program can i get for free or cheap?