Your best bet for music would be a larger REL.Cheaper would be a Vandersteen 2wQ.A Martin Logan would be good also.All are multiple driver subs which rather than one large 12-18" sub which are good for HT these rare faster and more pith acurate.The one hat is closest tom conventional good sub like Velodyne.If you can spend $2500 plus the new DD Velodynes are good but pricey.One obscure but very good music sub is he TBI Maggelan.They are single driver but unique in that though you can't localize bass below 150Hrz having two subs has adavantages.The Magellan's can be gotten powered but also passive and then mated with a singe amp/x-over unit they make.You can get one one than another and when you do since they are hooked up parallel you get higher output from both.Great review at www.6moons.com.Now is a great time to get a sub since you can latte add a Velodyne DSP/Remote unit which comes from their DD series (which let's yu do settings hooked up on you TV's display).Sells for $700 if I remember correctly.So you can get right sub for such a fine speaker and also get room correction added latter.
Cheers
Chazzbo
Cheers
Chazzbo