Best musical sub for a Triangle Celius?

Can anyone accurately define what a "musical sub" is? Probably not.

I don't know if I have a good set up or not. I have a HGS-12 and a HSU 10 inch with my Celius. The Velodyne always seems a little heavy and a bit slow. I like the Hsu, it's a light weight driver and seems a better match but doesn't go as low. I think I'd be happy with just the Hsu even though it's a very inexpensive unit. I just like the tone of it.
Thanx, Russ

I did a lot of listening. REL B series, M-L, Totem, B&W, etc.

Guess what blew everything away?

Paradigm Sub 12. The auto set up feature is a Godsend.

I was shocked. Not even close.