Subwoofers.... one 10" or two 8"?


I'm looking to fill out the bottom of my simple 2 channel system  (Musical Fidelity X-Ray CDP through Peachtree Audio Grand Integrated amp to a pair of Mirage OMD-15 full range speakers).  I occasionally will play the TV audio through the system for movies, but not interested in an HT setup. Music is the prime focus. The room is "medium" size.  I know that will not give the deep bass feel of a 12", but the difference should not be too great, and a 12" may be overkill for that room.  I've also considered getting two 8" subs to keep the sound balanced between the left and right channels. I think the  8" may be enough bottom for my room and tastes. I'm on a budget so getting a pair of anything bigger than 8" may not be in the cards.

Any opinions or suggestions as to whether I'd be better off with one 10" or two 8" subs?

















larstusor
If your crafty applying veneer is simple really buy a sheet table saw router and glue .. All those seem like strong reason . I hsve s sunfire hsu 12 sealed and small i am gonna geab another used at some point gloss blk .. They are a little more like 750-1000 each .. Congrats . I know everyone has there opinions but i spiked mine starsound audiopoints 3 made a huge difference.. 
@leotis -
I found that same procedure you recommend (setting sub's phase based on minimizing bass output at the crossover frequency while while main speakers are in reverse phase to sub).  It was actually in Sound & Vision and submitted by Robert Harley as I recall.  I didn't do the out-of-phase-on-the-mains part but did try maximizing dbs at the crossover frequency using a tone generator.  I will repeat the procedure to confirm but it seemed like a large change to my almost 0 degree initial phase setting was needed....going to 140 degrees! Both channels ended up at the same phase value and I was not trying to read the actual setting at that point...just going by ear with what gave the loudest sound.  Anyway, afterwards,  I was not very satisfied with overall impact on music.  It seemed like soundstage had collapsed and (lower midrange?) was weakened.  At this point, I'm inclined to agree with Erik that this method may have unintended consequences.  Based on what else I'd read about phase differing across a range of frequencies this is, perhaps, not surprising.  I'll probably repeat the experiment BUT I suspect setting phase is going to be trial and error based on the overall effect on the music and not just max db at the crossover frequency.
If you sum the signals from the sub and main you get +3 dB.(less after room interactions) If you cancel the signals with reverse polarity you get -40 dB. Much easier to hear! Method works best when the sub is close to the speakers. If sub farther away then differential distance from sub and main to different points in the room varies more, and result becomes more hit or miss. Then trial and error may be the best you can do. Maybe you are referring to Harley in Absolute Sound. http://www.theabsolutesound.com/articles/subwoofer-basics/?page=3
leotis - YES, RH of TAS. I might have muddled things together having read a couple of pieces about that  method including the one at the TAS link you provided.  I think RH contributed as well to the Sound + Vision article I read.  Did see his name...maybe in the comments section.  

The subs are located right next to the main speakers so that’s not a complicating factor. Some say not to go this way, others recommend it. The folks at SVS were okay with it as they say their subs do not have to be "boundary loaded".  They appear to be giving acceptable performance in this position and just need a bit of tweaking. I’m inclined to repeat the out of phase/phase setting experiment though as I mentioned results after the first attempt were not "ideal" in terms of overall impact on the music.