help make my box sound good!

[mixdamike]

I just built a custom speaker box for 4 10 inch subs for my 99 cougar. The layout inside the box consists of 4 squares individually sealed. I only have two subs in it right now, and im waiting to cut out the holes for the other two when i get them.
The prefab box i had originally, hit really hard. The new one doesnt sound so great, actually sounds like crap, But looks awesome. I only enlarged the size of the box by a couple of inches per speaker not thinking it would be a big difference. I was wrong! The only options i can think of are: Putting something inside the box to cut down on air space for each speaker, or tearing the box down trying to salvage as much MDF as possible and building a new one that doesnt look as good. What can i do?
Thanks
Mixdamike

[neomagus00]

depends on what the problem is. does the bass sound too loose and quiet? how much bigger did you make the spaces? are you sure it's sealed properly between the separate chambers?

if i had to guess from the provided info, i'd say glue a couple blocks of 2x4 in each box (the same amount in each one) and that should alleviate the problem. or, if you have polyfill in there, take some out.

perhaps you're not considering that you have half the subwooferage now that you did in the prefab?

[Vr3MxStyler2k3]

Did you seal it?

[Mixdamike]

Yeah its sealed air tight, with glue, silicone and expanding foam insulant. I was just thinking that maybe i could put some kind of mat in there, like an egg crate or something, to better hold in the acoustics. What do you think?

[Airplay355]

when u increase the size a couple inches, its not just a couple inches. you are dealing with volumes of air so its inches cubed. putting polyfil makes the sub act like the box is bigger. if you have it stuffed with polyfill thinking that it's going to take up space and counteract the couple inches you added on then you should probably take some or all out.

was the prefab box ported?

[Vr3MxStyler2k3]

You want some type of polyfill in the enclosure - SOMETHING to help cancel out the backwave...

[MacLeod]

Not necessarily. Polyfill cant hurt but you dont have to use it. If the box is built to the recommended specs the sub will work fine.

Using polyfill wont make up for using too small a box. I can help but its always best to use the right size box.

[Airplay355]

except his box is too big lol