I have a similar, but not identical, situation as the OP. Rather than starting a new thread, I thought I'd try to piggy-back here, as there's already some good information here and this thread is less than 2-weeks old.
I've had an Onkyo TX-SR606 driving the Polk RM-6750 speaker set (4 satelites, 1 center, and 1 sub, link here: http://www.polkaudio.com/products/rm6750
) for about 4-5 years now. I bought the Onkyo because, at the time, I liked it's connectivity, it's price (~$500, at least back then), and that it would decode TrueHD and DTS-MA. I went with the RM-6750 because, in addition to the Onkyo, I was also picking up a 52" Samsung and a nice looking piece of furniture to house all of this, and the budget was beginning to run a little thin. The idea was to eventually upgrade, but going with the RM-6750 instead of HTIB, I could do upgrade piece-meal.
I have a PS3 that I use for BluRay, and an XBox 360 that I use as a WMC Extender for a HTPC I have in the basement. I watch HDTV, stream NetFlix and HBOGO, and listen to MP3's through that 360-as-WMC-extender.
The "room" I'm in is roughly 20'x24', but probably 65% of the "back" of it isn't walled off; the floor simply transitions from carpet to hardwood, and opens up into the Kitchen and "Dinette" area that we use when we aren't in the Dining Room. The eventual "wall" for that 65% is the length of the house (40' wide) away.
This Christmas, I got a pair of Monitor 70's on the NewEgg deal that I think most everyone here knows about. I'm no audiophile, but I have to say, I love
them. It's one of those things where, even my wife, who is skeptical about virtually everything I do, looked at me and said "yea, I can hear a difference, those sound great" (at least compared to the RM-6751's we'd been using before this). I'm sure these are likely "entry-level" speakers into the world of "audiophilia" (sp?), but for me, it's a big and readily-noticable upgrade. My entire music collection has come alive and is all-knew because of these.
That said, for TV/movies, they were kind of overwhelming the puny RM-6752 Center Speaker I was using, so I hastily pulled the trigger on the Polk CS10 (the CS20 was about 1" too wide and maybe 1/2" too deep for the hole I need to put my Center Channel into directly above the TV). It's already shipped and coming tomorrow.
I started mulling over upgrading the Sub, too, and googling around to try to understand what I need to pair a sub with my AVR and speakers. My original concern was crossover frequency (based on what I've read, I'd like to set crossover at around 80 Hz as a starting point, and while my Monitor 70's and CS10 are well below that, I am still hoping to put those RM-6751's to use, at least for a little while, as L-R Rears, and wondering if I'll lose much if I set a crossover frequency below what my Rears are capable of producing). While googling for info on what to pair with Monitor 70's, I came across thread-after-thread (including this one) from multiple websites that suggested the "CS2" (not the CS10) be paired with the Monitor 70's. The following quote regarding "timbre matching" started making me sweat that maybe I'd just crapped the bed:
Originally Posted by postrokfan
If you're planning on keeping the 70s I would definitely get the CS2 for the center to ensure proper timbre matching. It's not that important that the surrounds match your front speakers. However, I don't think it would make much sense to purchase surrounds that outclass your front speakers (e.g. Ascend Sierra-1s). A pair of Monitor 40s would fit the bill. For your subwoofer, perhaps something like the HSU VTF-1 MKII would be more appropriate ($449).
The follow-up response, however, gave me a little hope:
Originally Posted by postrokfan
The C20 and the C2 should be very similar. The TSi series changes are pretty much cosmetic (i.e. the glossy cabinets).
So I guess my question is three-fold:
1) Is it safe to assume, in that case, that the CS10 is also fairly similar? Or have I made a big mistake?
2) Any thoughts on Subwoofer Crossover Frequency? Those RM-6751's will be
in use as my Left-Right Rear speakers for at least the next 12 months, until I get an opportunity to upgrade again. Would I be making a big mistake setting Crossover at 80 Hz?
3) Anyone care to recommend a Sub to upgrade to, based on this setup, and the following budget limitations?
a) At ~$215, the Polk PSW111 would be pretty easy for me to pull off (8" Woofer, 38Hz - 250 Hz, 150 Watts Continuous > 90 Watt max on my SR606)
b) At ~$375, the Polk DSW Pro 550 would squeeze me a little bit, but if it makes a difference, I only want to buy this sub once and not be left *wanting* (10" Woofer, 23 Hz - 160 Hz, 200 Watts Continuous > 90 Watt max on my SR606).
I don't need a sub to really *boom* and rattle the walls. I have a wife, an infant child, and a pet cat, none of whom want or need to have their eardrums assaulted by truly *massive* sound. But I would like to have a little *thunder*, on occassion, when I'm home alone with the music on and/or watching an action flick.
I'm not married to Polk. In fact, before I found that deal on the Monitor 70's, I was planning to go with a set of floorstanding Fluance speakers, and was weighing the pricing Pros-and-Cons of the SXHTBFR vs. the SV10... so the long and short is, I'm not determined to buy Polk, I just went with the Polk Center Channel I did because I was in a hurry and at this point I have a comfort level with the Polk product and website, and I felt like they were at a good price.
Any input on the 3 questions I posed above would be appreciated.