Two JL F212s verses two Velodyne 18 plus?

Exactly what is your sonic goal? Home theater with massive bass effect impact, music only with seamless low frequency integration, or both?

If you have the room and don't mind a large enclosure the ultimate and possibly most economical is a 400w ServoDrive bin which could easily be powered by a modest pro amp such as a fan less Crest or QSC, EQ'd using the Velodyne SMS.

I rented the small 2-18 for an outdoor gig, brought it home for a day and used my DD 18 for the EQ HT signal. Nothing on the consumer market even comes close to the low frequency energy the ServoDrive has on tap.

Mitchell has been around the block and I couldn't agree more. IMO, regardless of what brands you check out the Velodyne EQ, whether in the stand alone SMS or in their powered systems, is the easiest and possibly the best consumer method to EQ and integrate low frequency into a listening room.

I've replaced my single DD 18 with two DD 12+ in my two channel system with dramatic results. Velodyne has done their homework on the + series but I'm very biased.

Both, I utilize as home theater and listening room. One of my dilemas presently is finding a place to audition these subs.

If your dealer is close buy and he wants a sale,he should let you do a home audition especially if your dishing out lots of coin.
Been thru that a few times,if they don't I'd go somewhere else.
I'm a 3hr drive to a nearest dealer an hour and a half each way.Don't mind the drive if I can get what I want.

I have a local family owned electronics business that can get velodyne or JL at a decent price, but they don't stock any of them. I would have to travel likely five hours one way to attempt to find a demo. The two places I have dealt with before neither have any of these subs in stock to demo. Thats in both Portland Oregon and Seattle Washington.

That's a bit of a drive(one way)
whichever sub you choose hopefully she's the one as getting two gets pricey.
I went thru six subs and been looking for that live bottom end
sound(my dealer also)15's18's,and some W bins.
when I heard the 1812 in his huge room,I was literally blown away.
Mine is alot smaller and I figured,I could never get this sound in my room.
My dealer said,it doesn't matter the size of room.
We'll he proved it,I get the same sound in my 12X19 as he got in his 16X40X12 room,I couldn't believe it.
He brought it up for a in home audition and I wasn't committed to purchase.I guess he was sure that I'd like it.
The wifey made him dinner and I offered to help on his gas for the drive up.
Anyway I get all the lowend theatre I want,plus the midbass Punch for music,this is bottomend you feel up your backside
and doesn't interfere with what's going on above it.
Totally satisfied musically now,wish you could audition up here.