Myself, 1 sub. was great. A 15" Velodyne.Life was grand.
Once committed to a room evenly filled with sound.
My thought was, the 15" sub. was great for the rear.
I use a Velodyne FSR-18( just before the H.G.S.) in front, and a
F-1500 in the rear.
Both are very quick, and very musical.
Dialed in properly, they literally disappear!
Some how, Velodyne seems to get the max.
power to the cone, with such speed and accuracy.
Better than many others rated with more power.
Plus, with 2 subs, neither one is straining ever. so they
have plenty of headroom.
I have yet to hear an "Organ"/pedals at 16hz.reproduced
Similar to a seismic tremor's, the Velodyne's produce.
The Velodyne is as a Iron Fist, and the entire bldg.
flexes to the smooth waves of true foundation bass
reproduction.
Often "feeling", before actually "hearing" the music is not
uncommon.
Movies are so Dynamic, if I am not careful; Structural
damage,is likely, as well as kissing the crockery
and other glass kitchen wares good-bye. NO JOKE!
So really, you just have to go out and listen to music,
and listen to what the sub. does right, or wrong.
The big Bag-End sub. goes deep, but I was not impressed
with it's performance. Slow driver(18") sounds kind of
mushy,with fast electric bass lines IMHO that is.
In Conclusion: If you desire a big sub. 18", IMHO I feel
the Velodyne FSR-18 is going to be tough to beat, in any
comparisons. Plus I scored mine for a great deal.
I give Velodyne 5 Stars overall, for them both.
I can't think of any negative things about either one.
Enjoy The Music!