Custom speaker box, Looks great, sounds like crap- HELP!!

[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

[beyondloadedSE]

I dont really know much about sub boxes, but it is just more than building a box and putting subs in it. There is actually a science to the whole thing of how the waves inside the box travel. Btw, are you sure your wires are hooked up to your subs/amp correct?

[ponchonutty]

Yep, you can't just get some 1/4" plywood and go to work. I use 3/4" HDF and 1" to 1 1/4" HDF for extremely powerfull systems. Do you know what volume of air the subs needed and what you ended up with? What material did you use and how did you put it together. I usually use Liquid Nails and screw the sides together about one every 2-3" apart.