Jon,
I had them placed on the TV stand, and running them with LFE split from the receiver, using the Denon 1909's base management, crossing over the X-Statiks & X-Voce at 80hz.
Most of my comments are based on pure 2-channel music listening. I hate "home-theater" subs that always woof and boom, and I always use sub crossover point as LOW as possible, nowhere near 80 Hz.
For example, I have my ULW with my main music speakers ($$$ custom speakers that reach down to 29-30 hz), and I prefer the results with my mains run full-range with the ULW dialed in at the lowest frequency and volume that makes my reference music tracks sound natural, i.e. no low-midrange thickening with subs turned on.
ULW should be on the solid floor, not shelf, on spikes, and I have a walkway concrete slab (from my yard) on top of the ULW, which also helps me to *not* hear the sub enclosure colorations.
Also, common wisdom tells you to use the speaker-level input to "match" the character of the sub with character of your other speaker woofers, but I have achieved far better results using the line input. It just took experimentation with different interconnects to get the better result. I don't use the EQ knob, just the sub gain and crossover point.
So AV123 still doesn't have any more 500W amps to ship you?
Interesting comments, Jon - many thanks! I think my issue has to deal with listening at low levels, and missing the bottom range. I love the X-Statiks, but find that the sealed woofer portion leave A LOT to be desired in terms of output when listening at low volumes. I've tried using the Denon's Audyssey Dynamic EQ, but find I lose the entirety of the midrange. I end up listening at decently low volumes, and running my subs a little hot at the 80hz crossover (or even 100hz sometimes). Unfortunately what I gain in output I lose in dynamics. Hence my interest in the Servo Subs.
(1) I could probably place the subs out the outside of the X-Statiks on the floor, and play with a lower crossover. I find that if I don't cross over the X-Voce at 80hz, the speaker can get a bit boomy, but you are right on the X-Statiks being crossed over low - I like the natural rolloff.
(2) I am VERY hesitant to double down on AV123 subs given (a) failure rates of anything that requires a plug (b) continued lack of replacement amps for the ULW/UFW. I've heard that there is a drop-in PE amp, but I don't want to have that as a fall-back
(3) Room vibrations - the one aspect of the servo subs that REALLY entice me is that there is no room decay, which would be VERY apartment friendly.
I'd obviously like to save myself from having to buy an additional amp, making this exercise cost prohibitive. But the one aspect of the ULWs I value the most is their relatively low profile. I would like to build the SMALLEST possible footprint for the SW-12-08s if I got them... hence my question about the 1 cubic foot PE box.
