Get 2 of them and get crazy. In order of performance; lower to higher. Im having dejaVue, have you already asked a bunch of sub questions?Leaning toward getting the HSU VTF-15H MK2.
20x25 room with an opening to the kitchen and hallway.
What other subs do you recommend in the under 1.5k region?
Looking into the FV15HP as well...
HSU VTF-15H MK2 (Bang for the buck CHAMP! Go dualdrive!)
PSA TV15HP (the Rythmik and PSA are interchangeable probably)
Rythmik FV15HP (go 2 if you can. Brand new with more power!! @Soulburner is testing a pair out now)
Now, 18's in your 4,000+ cube room is a better bet, but dual well setup 15's should be respectable.
List doesn't change, other than the HSU falls off and JTR climbs on, with an attitude and desire to rearrange molecules.
All of these subs have been coverede in every "Sub Help Please/I Need A Sub/Best Sub for My Room/Got 300 Dollars Burning A Hole In My Pocket, Which 15" Sub Should I Buy" threads. There are probably 30-40 of them in the last 6 months. Feel free to search.