Question regarding subwoofers


I have an RHLabs SB-1 that’s served me pretty well for many years and use with it with my Acoustat 1+1s. (Had it refoamed a couple years back.) As well as the 1+1s image, I’ve always been slightly annoyed by having a single subwoofer between the panels. When playing something with a large sonic image like orchestral music the setup works fine. However when playing something more intimate like Jazz it’s easy to "see" where the lower frequencies are coming from: The middle. As my listening has gotten more refined it’s getting to be less acceptable to me. So I’m looking possibly at a pair of smaller, powered subwoofers. Why powered? Simple: If I do this, I’d rather the ARC VS-110 just power the panels. So, my questions:

1) The SB-1 has a single 10 or 12" driver. I’ve seen subs anywhere from 8" to huge. What folks experiences been with a pair of 8-10" powered subwoofers? Too much? Not enough?
2) Did a pair of subs affect imaging much? IOW, could you discern enough left/right to make it worthwhile?
3) How tough was it to balance them?
4) Do I run another set of interconnects from my SP11? Or do I get a set of Y adapters to feed both subs and amp?

Let me close by saying that like with most things audio there’s going to be a lot of "it depends". I get it. But I’d still like to hear of folks’ experiences as I do see a lot of systems with subs.

As always, thank you much for your time and comments!

128x128musicfan2349
Ah, for those not familiar with the SB-1 subwoofer, it is passive: The power amp's speaker output goes into the Sub where it passes through the sub's crossover. The upper and mid signals then comes out of there to the full range panels. Inside the sub there's a crossover but it has no adjustment, no internal amp. On the back of the sub, there's a volume control. Unfortunately I never had the proper manual, only the manual for the SB-2 which says it was selectable between 60 and 80Hertz so I'm guessing the SB-1 was at one of those two points. BTW the Acoustats by themselves are pretty gutless down low. 

@millercarbon: 5 subs? LOL I've visited your virtual system. Perhaps in our next home I'll have a single-purpose music room but for now, a 'swarm' of subs is out of the question. (Besides, I rather enjoy my current wife.) However I must disagree with your implication that bass is non-directional. I have moved the subwoofer in the past to different locations and please believe me when I say that I could tell you where it was (and wasn't) in the soundstage. 

@rego: I'm encourage by your statement that two 8" drivers move as much air as a single 16" driver. I will research that a bit further.
I only have room for one Sub and can only be position to the left of my Maggie's My Sub is the SVS Ultra 13 and is crossed over at 70 Hz
through my Oppo BD 105  blu-ray player
When l listen to music with extensive bass l can't tell its coming from my sub but rather within the sound stage of the music 
I have a single 8” dual vc Velodyne DLS (Servo) powered sub. DSP crossover. Remote control. -3 dB at 32 Hz. I have it crossed over at 100 Hz. Bass always sounds like it’s coming from wherever the imaging says it should be, whether center, back, left or right.  Plenty of clean and articulate bass for me. My main source is vinyl; very few LPs go below 30 Hz, so it’s perfect for my setup and my tastes. I listen to all kinds of music, mostly. I just can’t justify these other bass everywhere setups.  
Some subwoofers offer a great deal more in the way of calibrated filtering and  adjustability without digitizing the rest of the system and may satisfy your needs in your room.  

I believe jrwaudio's SVS Ultra has an easy to use auto setup process that also allows the user to manually tweak things to taste as well as some adjustable presets. Check out the Ultra User Manual on line. You'll get a better idea of useable modern processing and connectivity. Have fun with it.

@musicfan2349 if you can easily locate your sub in your room then it is not integrated well, one way or another. Either crossed over too high, gain too high, or some combination of placement and the others. Some rooms are very tough to nail, and that is where the multiple sub concept works. It is possible to integrate a single sub and make it “disappear”, but that requires speakers that dig down pretty low and a cooperative room/setup. Overall, it is much easier to get 2+ subs to integrate as a whole. But one can be done...