I have been reading with interest about the latest subwoofers in this Forum and whether or not to have 2 subwoofers is recommended. I am finding it difficult to understand some of the things that have been said. My main system consists of 3 M&K K7s, 4 M&K K4s and 2 M&K VX-100 subwoofers. I have a Denon AVC A11SR amp. My bedroom system includes a Def Tech Pro80 sub/sat system with a Pioneer VSX 1014 Amp. All of this kit (except the upstairs amp which is fairly new) has been running for about 3 years. I got a second sub for the main system to balance the bass. The subs are at either side of the room near the wall and in front of the left and right speakers. They seem to perform well. In my bedroom, the only place I could put the sub due to furniture was in the rear left hand corner. Unfortunately, I can often hear where the bass is coming from (even though you're not supposed to be able to) which is one reason I got the second sub downstairs. I am likely to change my downstairs amp this summer, probably for a Pioneer AX5AI (because I like the performance of its little brother upstairs), but I am tempted by some recent price reductions on the AX10AI. However, I would like to understand subwoofers a little better, as I am tempted to make some changes there also. I placed the downstairs subs where they are because I didn't know any better and because it seemed a good idea to spread them out (to me anyway). I have not spent very much time setting them up, but they seem to perform well. Noting recent comments on this site about it being difficult to set up 2 subs. I have just tried out the opening sequence to Star Wars Ep 2 a few times, with both subs and then with each one on its own, and I didn't notice any distortion (other than a shaking door!). It definately seemed to have more impact with both subs on. For reference the amp was at -23dB and both subs had their own bass levels set at +3dB. I would be grateful for any clarification on how I should have set this system up, particularly if it will improve it. My other point is a question regarding the subs themselves. I have been impressed by the positive comments regarding the BK XLS 200s. Given their larger drivers and amp (the VX-100 only has an 8" driver and 100 Watt amp), would I find 2 of these to be better than my 2 M&Ks? Noting of course that the M&Ks listed at around £800 each, whilst the BKs are less than £300 each. Or is it still a case of 'you get what you pay for?' When I originally demoed my M&K system, I really wanted an array of MJA Pro 50s or 100s (because the 50s had just come out, they were getting good reviews and they were very inexpensive compared to the M&K - also the K9 sub which went with my system was not too brilliantly reviewed at the time and seemed overpriced). Anyway, the demo MJA didn't seem to perform very well, the K9 was as expected and the VX-100 was definitely better, so I got that. Sorry for the long post, but I would like to understand subwoofers a little better, with specific reference to placement and the quality of other types compared to mine (particularly the M&Ks). I cannot house a very large sub, so I am only really interested in the compacts.