Yeah, one reason I would never buy another powered subwoofer (amp inside subwoofer).
From now on, just buy non-powered subwoofers (subs that do not have amp inside). They are also called "passive" subs.
I also have 4 Velodyne non-powered subs in my family room.
If you had a non-powered sub, you could easily use a Crown XLS amp and the sound quality would be just as good IMO as long as you let Audyssey XT or XT2 EQ the sub.