Thanks Gonk-
Yep I swear this is -everyone's- first thought. Why the heck hook up the high level??
I mean, we all have crazy uber pre/pro's with bass management and low level output!

The REL is an integrating component and uses the high-level inputs to 'see' the same signal that the mains see, which gives it ability to take on a more identical sonic signature with the mains.

You need to read some of the REL Storm reviews, their approach is very unique and it does produce extremely nice flat and seamless sub-bass with any main speakers. The REL is a 'sub-bass' woofer and is meant to be crossed over at 28-30hz. The amazing thing about these subs besides being able to cleanly reproduce bass in the lower range is their ability to let you really hear / feel tonal and transitional differences in the low bass range vs. 'boom boom boom' like most subs.

Here's a good review: http://www.audaud.com/audaud/OCT01/EQUIP/equip3OCT01.html
Here's REL at CES2001: http://www.ambrosia.com/CES2001/rel.html
And one more review: http://www.soundstage.com/candystore/candystore200312.htm

I STILL need help! My REL will be here on Tuesday!!