Stuffing sealed enclosures?

I have a Q-Logic dual 10" subwoofer truck box providing 1 cu. ft. capacity in each chamber with two Infinity 10 woofers mounted.  I seem to get a little bit of sound reverberation (for lack of a better description).  The sound seems to go on and on after the note has been played, like an echo if you will.  There presently is no lining or stuffing in the box.  I want tight clean bass, some music gives me that and some doesn't.  Will stuffing or lining the box help and if you which do you recommend?

Thanks

Markcars,

I am using a Sony XM-DS1500P5 mono amp.  I've heard some negative remarks regarding Sony's amps but I'm not gonna push it as hard as some of these other guys, too old for that.  The subs are wired correctly for a 2 ohm load. 

DYohn,

Enjoy reading your posts.  Articulate and your well thought out responses draw a very clear picture for us beginners. 

Cheers