Pair of 1 chamber boxes, opposite sides of trunk: separated or connected?

[ModernDayHero07]

My question is very specific and complicated. I have 2 SA 8v.2's and I want to put each one in its own fiberglass sealed box on either side of the trunk where there is a void in the trunk wall. The thing is each void is a different shape and size. Basically both trunk walls are different. This is for a 2007 Ford Fusion. I am powering both subs with the same amp. I know it is very important that both enclosures have the exact same volume. And since each void is different it will be difficult to make each box have the same volume. So I was thinking could I somehow combine both chambers into 1 chamber while still keeping them on opposite sides. I was thinking via a tube. Like a pneumatic clear tube that is like 1-2 in diameter. But I don't know if this is legit 1 chamber. How big does a thing have to big to join two chambers? Is what I want to do even possible? I am open to all suggestions.

[timc31610]

I believe it would have to be much larger to prevent it from acting like a port. Also if you had a 2" or 3" piece of pvc running across your trunk you may as well build a small sealed enclosure to go up against the back of the seat. Here is an idea, since the boxes will be fiberglass they should be waterproof, make both boxes, fill both with water then measure the volume. Adjust the larger enclosure to the smaller ones size by glassing in small pieces of wood until the volumes are equal.

[slowfkncar]

If its fiberglass, you can build the smaller enclosure first,measure the volume by liquid,save the liquid measurement and try to get your second enclosure as close as possible.

*whoops,timc already answered that. Sorry

[Triticum Agricolam]

Since these are going to be sealed boxes its not nearly as critical that they are exactly the same volume as ported boxes would be. I get them as close as you can and call it good.

[timc31610]

Very true Triticum but one question. At what difference in enclosure size would there be noticeable difference in output?

[Triticum Agricolam]

Very true Triticum but one question. At what difference in enclosure size would there be noticeable difference in output?

I can't give you a number, but with a sealed box I think you would have to try pretty hard to get enough difference to be noticeable.

I did a quick test modeling a SA-8v2 in a .65, 1.3, 2.6 cu ft boxes. There is barely 1 db of difference between the different sized boxes from 20 Hz to 100 Hz. You will never hear 1 db of difference and that's with one box 4 times larger than the smallest one.

Using a different sub you may get a larger change, but not with the SA-8v2.

[timc31610]

Thank you for the quick answer! Never hurts to ask and learn!

[ModernDayHero07]

Thanks a bunch everyone! Very helpful! I was thinking about using water to test volume but was thinking about it in the wrong order. But anyway, thanks a lot again!

[P4killer_]

You should be fine. If anything I would try to design an exact same enclosure for both sides. W.e will fit in both sides and glass it into each corner as needed to make it look good. But the actual box part of it would be identical.

If not, I think your still fine. The woofers wont counter act each other too much if barely at all if the boxes are close enough. But they might react differently which means when their wired in parallel to same amp, one woofer will see a different amount of power.. but again if its close it should be minimal difference. It wont hurt the amp any..

You could run sep amps and adjust if needed. to further minimalize the difference.

But you should be good.

[gr8handogoatness]

You could also put a little bit of polyfil in the smaller one to make it "seem" bigger. That would still be just guessing but it might help be a little more close to exact, but like they said, you wont notice it if its close at all.