I have this 10in DVC (2ohm combined) Kicker sub in a very small sealed enclosure and it is amazing..
Kicker Solo Classic 09S10C4
Can't believe it's only $99.. I paid $120 and it was on sale- Amazing ssubwoofer.
Takes up very little space but sounds like it's a very large encloser--
Sound Ordnance Bass Bunker
Sealed single 10" subwoofer enclosure (Model BB10-50S)
Anyone interested in a small sealed box needs to look at that combo-- I'm running 500 watts RMS 2ohm and it is more than enough to rattle my rear view off the car if I want (which I don't) I just use it for a nice seamless amount of accurate, deep, smooth bass.