Sealed enclosure too small?

So I got my new Eclipse 10's installed in a custom box in the wheel well. Since they are new, I was expecting some tightness and sound issues. I wasn't trying to get my hopes up too much about the sound quality and db output, but in a previous thread 2-10" Eclipse in a ported enclosure hit 142db. So I was expecting something in the vicinity. When it was getting installed I noticed how small the box was. Pretty much just big enough for each sub to sit in. I did read the specs and it did say for a sealed enclosure the recommended air space was only .6 cu feet. so just a little over a half a cubic foot each sub. I have ample power going to these subs with the Diamond Audio 1200.1. I'm not real happy with how it sounds or performs and was wondering if my problem is the size of the box, or just the way it is setup with the subs in the wheel well firing up. I haven't got a real chance to play with the amp settings or anything like that since I am having a remote wire issue that is not allowing the amps to turn on...yeah. Hopefully thats just a minor glitch and then I can take what is suggested in here and try it out first. I know the gains are set too high as it is and I'm going to go through setting that all up from what I learned on here.

I need more bass. So far my 2-12" HX2's blow away these 10's as far as pure rumble goes which is disappointing. so any and all suggestions are much appreciated. Thanks.

Sorry, they are the 7104 DVC. the new aluminum ones. It is sealed firing up...not a prefab box. So I was thinking closer to 1 cu ft. myself when I took it in for install, but the installer and I were both looking at the manual and saw that they recommend .6 like I said. this is going to be a real pain in the ass if we have to change this box....really it is.

I'm actually thinking of buying a cheap pre-fab, slapping the subs into it and seeing how it sounds then. If it improves it is going back to the installer. I'm sure he won't be happy if this is the case....too bad.