need to find subs with lots of slam for HT

hi all, i have a small theater room. it is 12x14 with an 8 foot ceiling. i currently have 2 velodyne cht-10 (10 inch $650 each) subs. i use a svs pb 13 ultra set in 10hz mode to handle the super low frequencies that the velo's cant. i set the svs's x-over as low as possible. it shakes the room which i love, but... only from about 30 hz and below. i want to leave the svs as it is because if i allow the svs to accept higher frequencies while tuned to 10hz, the bass becomes sloppy at the higher frequencies. i have a integra dhc 80.1 with audyssey which calibrates all my subs.

i have not tried different subs in my theater room. many years ago i tried a dahlquist 12" ($900 sub) and i remember i could feel the bass more. i'm sure it had a bit better low freq. extension but maybe it was just more powerful? moves more air? 12 inch perhaps? i dont know how all these factors come into play when choosing a subwoofer. i got rid of that sub and got the 2 velo's mentioned above. there doesnt seem to be as much slam from the velo's. are they too low end i wonder? now i want that HT chest slam, as i have upgaded pretty much all my equipment but still have those velo's.

so this is where i am confused. i want the tightest bass with possible with alot of chest caving slam. i dont know if a couple of small 8 inch(say sunfire super juniors for example) would give me the result i'm looking for due to its small woofer size. i'm not necessarily looking for low frequecy extension because my svs handles that.

do i need to get into the 12 or 15 inch subs for the slam? possibly super highend 10 inch like the jl fathom f110. i dont want big if they produce flabby/sluggish bass. i should mention that i have bass traps in my room as well.

however, my room is 12x14 with an 8 foot ceiling so i dont want to throw money away on subs that would be overkill. i definately dont want bass overhang (sloppy bass) that some big subs may produce in small rooms.

can anyone suggest what subwoofers (model and size) i would need to achieve alot of clean bass with alot of HT slam for my small room?
i dont necessarily need the most exspensive...i just want to be happy with tight clean bass and enjoy the punches on my chest!!!

thanks and much appreciated,

The trouble with cheaper subs is that they either use a small driver (for tightness), or large driver (for depth), but don't give you both. I don't think adding subs fixes the problem.

I also have a small room (13x15) and use a Velodyne Optimum 8. It gives me all I need, but admit it won't rattle the windows.

I suspect you need a high powered sub with at least a 12 inch driver. The SVS ultra should do the job, but I guess you feel it doesn't.

You can look at the Velodyne Optimum 12 , the DD series or the JL audio Fathom 110. They should all do the job.
Post removed 
thanks guys for your response. here is exactly what i am doing. i set the svs at 40hz (lowest) with the x-over on the back. i run the audyssey with all 3 subs. the bass is ok but i feel its alot better after i tweak it. heres how:
i use the eq on the back of the svs. i lower the 30-40 hz range as much as the eq allows me to. then turn it up about 8-10 db's. the result is awesome. the whole room shakes and i feel the hits right on my body. this may not be correct but it is very cool when each punch and effect literally shakes you. i know that my velo's are the weak link, therefore i want to find subs that produce excellent slam in the higher frequencies that my svs does not get. not sure what i need tho...8/10/12/15 inch, which models etc for my size room.

i've tried running just the svs in sealed and its good but no where near the super low frequency boost that im looking for. in sealed mode (svs) if i turn up the sub level, all the frequencies up to 80hz get boosted...which sounds terrible bass overkill.
its like you said bob, you get one or the other high bass or low bass from the woofers but not both. i am trying to get both with multiple subs. i just need some advice on how to acheive it.

your thoughts or suggestions?
I run a SVS PB13Ultra with center foam out. I have a custom 45LB-2 inch solid Parka wood platform with cone feet and Synergistic Research Miggs between sub and platform with amazing results. Great pitch, solid defined bass, tight and very controlled.

I noticed with the very low profile factory rubber feet on the SVS it vibrated everything too much which caused me to buy the custom Hifi Pyon platform that resolved the issue with additional positive qualities.

My Onkyo Pro processor is set at -12 with the sub dial at its detent and I still get the best bass ever heard of with lots of room to up the volume to rip my chest open.

The only upgrade I would do is maybe a Paradigm Signature Sub 1 or 2 if funds allowed. I think six 8inch sealed drivers or six 10 inch sealed drivers with 7500rms/9000peak would definitly rip your chest apart and your neighbours chest down the street. That would be World Class at a big $6500 tag. But you would never worry about bass again, just broken ribbs....LOL.
Just throw in an Outlaw ICBM crossover, set at 40hz cross,and drive the bigger sub(s) under 40hz, and the smaller 8 to 10" subs at 40-80hz, leaving your pre/pro or receiver to cross over at 80hz on up to the speakers! Of course, you still have WAY WAY WAAAAAAAAY to much bass energy in that room, which isn't being absorbed well enough by the room to balance out the rest of the midrange and trebble (then again sounds likel you go for the boomy bombastic earthquake bass sound, with about an hour or two of reverb and undecayed bass energy,overpowering the rest of your system, sounds like). This is all not to even mention the fact that your room won't properly support anything much bellow 20 hz anyway, and will never sound anything like a large space will, offering speed and inpact to the sound through proper decay and lack of bass modes. Basically, you're stuck with some small room acoutics issues that only radical acoustical renovation can help.
All that and how well do you know how to place all those speakers in the room to actually balance out and sound good in the room / setup? Lots to go wrong there, regardless of how many cute little subs you throw in there.
For you I'd be getting one large M&K MX5000 or perhaps some Earthquake 15" sub, and stick in rignt in the middle of the front wall of the room, anchored between the mains, and forget about it! Otherwise, find a better deal on a Paradigm Studio 15, and EQ the crap out of the the whole thing.
Wow...bass freaks...all of ya.
The Seaton Submersive HP, a 2400 Watt dual 15 sealed sub, has the highest performance to value. It easily competes with megabuck subs and is much better than most including the well regarded JL Audio Fathom F113. It is highly transparent and tight, reproducing deep bass effortlessly with serious power and no overhang, and, can play as loud as your ears can tolerate with low distortion. Properly set-up it is not localizable. Where most subs starts rolling off at or before 20 HZ, the Seaton maintains it power to well below 15Hz. I am using it with Dunlavy speakers crossing over at 100Hz. It is equally adept with music and movies. Another excellent sub is the Talon Roc. Good luck.
By the way, I am using Outlaw's ICBM (crossover amazing product that I have had for 10 years)and the antimode 8033 sub eq which I consider to be a fairly good product.