Hi, I have a '85 Camaro and I took a diagram for a box to replace my crudely built rectangle that sat against my hatch lock.

After removing this metal contact, would this prevent my subs from hitting as hard and rattling the car as before?

Should the new plans include a divider between the subs?
I didn't see any complaints on the page (Found on this forum)

and I went back with liquid nail and prevented any air leaks.
Removing carpet from around where it sits, possibly?

Any feedback would be appreciated!
Thanks.

Any rattling is wasted energy....you can subdue it with foam, dynamat (or similar materials), etc... A divider is not necessary, but preferably send a mono signal to it... so both speakers are playing a single channel instead of 2 different ones each... If it sounds "sloppy", a divider may tighten it up, plus put some poly fill / pillow stuffing in it, Walmert for a few bucks...

I meant it's so weak that it won't rattle the car, not the negative term, I apologize.

With my HU up to 75%, I can put my hand on the license plate with almost no vibrations; meanwhile my 12's are going at it fierce.

I removed the carpet in the rear to lay it against full metal as a contact, but it didn't help. I put my old rectangular box and it hit like a champ. The only two variables left would be the cubic feet and a divider being different between the two.

The box is 2.075 cu.ft - which is a lot larger than my rectangular box.
I guess i'll measure it out tonight and try a divider.

My Sony Xplod 1000W is a hand-me-down from back in the day, the only variable I can change is the voltage; would anyone have a tip on tuning this?
There's no Car-Audio shops within driving distance on a weekday for help.

Be sure both speakers are wired good, use a AA battery + to + wire and - to - and see that the speaker pops up / out... Only other thing I can think of, the sound waves were bouncing off the lied, and back down into the trunk before going out into the cabin and it seemed louder...

With the new box, almost no vibrations can be felt through the vehicle, and the very little sound it produces almost sounds muffled. I've caked the outside and inside with liquid nail and there's no air leaks. But the position of the old box vs. the new shouldn't make a difference whether I can feel the bass hits or not, should it?

Everything can make a difference.... having the sides open (old box), windows open / closed, the new box with closed sides changes the air space in the car... again, check wiring, if one is pushing and the other pumping, or just one is hooked up internally, way lower sound...

Perhaps the woofers are wired reverse polarity of each other. The music is causing one cone to go out-in, and the other in-out, and the are canceling each other. Try reversing the wiring on ONE of the woofers. This will reverse the phase of one woofer, and put it in sync with the other.

With you having 2, 12" Subs in the rear and your HU up to 75%, you should be rattling the next county over regardless of which box you have in there.

I have 2, 12" in mine driven by 500W Alpine, Mono and HU is Alpine also. I had to tune the he** out of the HU with all the settings it has. Finally set the distance from subs to driver and it came right in. My setting is around 10% and it hits hard.

Check your SUB phase on the HU also.

I'm with MoJoe...I think your subs are out of phase. Unplug one of them. Does the system get louder? If so, reverse the + and - on one of the subs.

Like they said....

Try unhooking one and see what happens

I'd put a divider in that box either way. I'm sure the subs fight each other with that shared airspace.

A divider can actually reduce output, due to a lack of acoustic coupling. Most people wouldn't notice any reduction, because it's usually less than 1 db, (Most people can tell there is a change at less than 3 db).

Also please stop using the word "phase" when you mean "polarity". They are two distinctly different things and the terms are not interchangeable.

"Phase" is a time dependent property, where are "polarity" is an electrical property.

You can have speakers that are "out of polarity" but are "in phase". This generally happens between different frequency sets, as in polarity could be opposite on the midbass speakers, but are in phase with the midrange speakers. There are many reasons for that, distance differential between the two speakers, types of crossovers used and direct or indirect listening position.

When discussing the above where the wires to the sub woofers could be wired opposite, that is opposite polarity, and polarity only.

It does sound very much like they are out of polarity. Changing the size of box between what you had before to what you have now will not have that dramatic change on output.

Also... someone recommended polyfill to help cure the "bigger" box syndrome. This is false information too. Polyfill slows down the sound waves inside the box making it play more like a larger box than it really is. If you want to make the box "smaller" inside, you need to fill it with something solid. Screwing a couple of pieces of 2x4 or something else to take up space inside will do the trick. But as Six_Shooter said, swapping the box shouldnt have that profound of an effect on the output of sound.

I didn't suggest it as a way to help cure the bigger box problem...
Agreed as you noted, I just said to do that so that there are not so many flat sides the sound waves are hitting / bouncing off of...

Sorry, I just read it combined with the previous statement... A divider might help tighten it up, plus add some polyfill. Just sounded like you were suggesting the polyfill to help tighten up the sound.

To the OP... another vote for reversed polarity of one speaker. I also vote on the divider if you are running each sub on it's own channel. If it's monoblock or a single bridged channel for both speakers, then the divider doesnt matter quite as much.