Alright, today I removed the box and subwoofers ( 2 Atomic Apocalypse AP15) from my car today to work on my rear deck. Well, all I did was remove the speaker wire from the outside box connection and took the box and subs out all together. When I finished with my rear deck, I attached everything how it was and tried it out. Apparently, when I turn my subwoofers up, the subs sound as if they are "hollow" instead of making a deep bass sound. Note, this has never done this before. I adjusted the gain, LP filter, and the equalizer on both amplifiers. (mono-channel amplifier to one subwoofer) Then I adjusted the equalizer on my headunit and made some adjustments there, but yet still produced the "hollow" sound. I know this is kinda hard to explain, but if you have any questions LMK, and ANY help is appreciated.