2 12 kicker solo-barics

i have 2 12" kicker solo-barics.  These are the older s12d round ones.  The subs are 8 ohms each.  I also have an 850 watt(bridged at 4 ohms) kicker amp and a 1 farad cap.  So I wired the subs in parallel to be at 4 ohms.  But they sound like doodie.  The bass does not hit clean and tight at all.  It is real boomy.  The amp has a crossover option which i hooked up to the low option for under 75.  But that didnt help much.  Do you guys have any input as to why they arent tight at all? 

What kind of enclosure are they in??

1 sealed enclosure

Internal volume????

.68 cu ft

.68 total, or each? Either way, that's AWFULLY small for one, let alone two 12 inch woofers. WAY overdamped. Secondly, they're Solo-Barics. Not remotely an SQ woofer. Thirdly, (and this is my opinion speaking this time) it's a Kicker amp. That, too, not exactly an SQ piece of gear. See where I'm going with this? IMPO, one should avoid Kicker at whatever cost if SQ is even a minor design goal when designing your system.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."