With my original setup I had the Kef 107's in the front corners and the LFM1+ to the right of the seating position. However, I wasn't happy with the sound for a couple of reasons:

1. During certain movie scenes it sounded like I was overdriving the LFM1+ and
2. I could hear some directionality on the low frequency sound and there was a "hole" in the response to my left side.

Adding the two LFM1 EX to the system I learned that problem one was actually a resonance in a glass fronted cabinet adjacent to the subwoofer.

Moving the LFM1+ to the front of the room and placing the two LFM1 EX to the sides of the listening area solved problem two. The LFM1+ will eventually go somewhere else, either resold or moved to another room.

In answer to how it's connected; there's a Y adapter hanging off one of the two subwoofer unbalanced outputs on the 990, with the third sub connected to the other unbalanced output.

On music the bass goes deeper than I imagined. I though that I'd heard all the low frequency on Pink Floyd's _Dark Side of the Moon_ with the Kef 107's (flat to 21 Hz, off 3db at 17 Hz) but with the subwoofers I heard new notes.

With the volume up on movies I feel the furniture shake under me.

Life is good.