When I first hooked these up, stereo music playback wasn't all that impressive since I was running SVS PB-2000 Subs using LFE only combined with 20+ year old MP3 files from my aging digital library. So I put music playback on the back burner and focused on multi-channel surround for movies whilst I built the new subs (Servo Sub 4) and then the A/V-1RS surrounds. When I initially replaced the SVS subs with the Servo Subs, music playback was still lacking even though movies were amazing. And that's when I realized that during stereo music playback the subs were sitting at idle (no LFE channel in the tracks).
I had read here before that the best configuration for a theater was to use high-level input on the Servo Subs and put another sub (or two) at the back of the room on LFE, and that's exactly what I did. I connected the speaker cables from the AVR (soon from an Odyssey Kismet 3-channel amp that's on order) direct to the Servo Subs and jumpered them using leftover wire from my A/V-1RS build over to the X-Statics. Good Lord, what a difference!
Even movie playback got better because all of the high-bitrate music tracks took full advantage of the Servo Subs (which was my initial concern with this configuration, and it turned out to be unfounded).
I sat back in my primary seating position, fired up some of those same stereo MP3s, closed my eyes and settled back into my theater seat. For the first time in my life, I was able to pick out all of the instruments and vocalists in 3D space. At first I thought the tracks tapped into the surrounds, but that wasn't the case. I was hearing full 3D from two speakers. And I don't even have the speaker placement or acoustical room treatments optimized yet (nor do I have the spiked feet on anything yet). As some wise old man once said, "You have taken your first step into a larger world."
Cue The Monkees: "I'm a Believer"