9.2-channel solution needed

So I moved into a new house a few months ago. This house's home theater was missing a few things, namely a projector, projection screen, and speakers. However, there is a place for a fixed projection screen. We have a sheet hanging there now, hope to get a real screen soon. The theater room has 6 holes cut out in the ceiling (the holes are 8 3/4" in diameter). It also has 15"x17" (approx) holes in the drywall for front and left speakers, and a 24"x15" (approx) hole for the center speaker. Wires for all speakers are already in place... which is how I came to realize that it is wired for 2 subwoofers, one at each end of the room (one is behind the screen, the other is at the back of the room).

This gives me holes and wires for a 9.2 speaker system. I have looked online and the least inexpensive (MSRP approx $1500) 9.2-channel receiver I can find is the Onkyo TX-NR1007
This receiver is more than I was hoping to pay for. I found it for around $1000 on the 'net but that is still too expensive. I was hoping to spend much less (I'm no audiophile, I believe there are decent 7.1 receivers for around $300).
So the question now becomes this: what can I do with $300 - $500 for receivers/amps in order to get all 9.2 speakers to work? I don't really need 9.2 channels. I would be happy with a 7.1 system using two sub woofers (or even one) and the left and right channels on two speakers each (or rear channels on two speakers each). I just want to use all of the speakers in my ceiling. If I only wire up 7 speakers and a sub, then I'm letting two speakers go to waste (or leaving two ugly holes in the ceiling -- I haven't bought the speakers yet).

How can I have 7.1 sound played on 9.2 channels? (I'm ok if some of the speakers are just mirroring others). Ideally I'd like to hear someone respond with "such-and-such company is reported to be coming out with a $400 9.2 channel reciever in the next few months"... in which case I'd wait. But if 9.2 channels is going to remain in the $1000+ arena then I'm willing to settle with 7.1 spread out over 9.2 speakers.

Any ideas?

BTW this is my first post on this forum. Look forward to being part of this community.

I'll have to gather some measurements....

Thanks. So I understand it would be possible to use two more speakers given I have an extra amp.... I'm not very knowledgeable about audio so my question now is, would I have any volume problems using an extra amp? What I mean is, will I have to always be adjusting two volumes (one on the reciever, another one on the extra amp) ?  If not, what features should I look for in the receiver/amp to make sure of this before I buy?

And yes, the two subwoofer cables are not speaker cable, but coax. Why do the subs need coax but the speakers not need it? I know coax is a higher quality conductor because of shielding (so it reduces interference, etc)... but why would the low range need a better conductor than the regular speakers? Just curious....

Here are the measurements. Notice feet are NOT in "feet,inches", but rather in "feet.decimal" ... (so for example 5'6" would be recorded in the table as 5.5 which means exactly the same thing, if you think about it). I have heard that the first row of seats should be 2 screen heights away from screen. As it turns out, the first set of ceiling speakers (shown as circles in the image) is almost exactly 2 screen heights away from the screen. The image is to scale... 30 pixels = 1 foot. Seating is not pictured because there is no seating yet (I still need to buy a couch). There are no fixed seats. Seating can be wherever we want it to be. The projector has been installed. The center, front, and left speakers are behind the screen. The floor does not slope.. it's flat.

	feet
width of room (approx)	16.5
length of room (approx)	24.66
height of bottom of screen	1
distance to rear speaker from back of room	5
distance to rear speaker from sides of room	6.33
distance between rear speakers	3.75
speaker diameter	0.67
distance between two side speakers (on the same side of the room, measured along the length of the room)	4
distance from side wall to side speaker	4
distance from screen to nearest side speaker	11.5
distance (along length) from rear speaker to nearest side speaker	4.875
length from screen to projector lens	15.25
ceiling height	7.5
screen width	9.25
screen height	5.75
two screen heights	11.5

 Thank you. What I'm still wondering though is what it would take to get an amp setup on those extra speakers without needing to always adjust 2 volumes. Is there a special feature I need to look for in the receiver and/or amp? Or is this something that any modern reciever/amp pair can handle? I don't know what I'm talking about here so I'm not sure of the words to use to ask this question properly. And how would I wire it? Would I wire the two side channels from the receiver direct to the amp, and then from the amp to the four speakers? If this is the way to wire it, would I need to tell the receiver to output a pre-amp signal for just those two channels but an amped signal for the rest of the speakers (besides the sub, of course) ?

The floor is carpeted.

Also, the ceiling is only 7.5 feet high (and therefore the projector hanging lower than that), so if the second row of seating were on a riser, people will probably bump their heads on the projector while getting in/out of the row. But Dave, you're right, in order for them to see the screen I think that they would need to be on a riser. 

About the subs... The center sub is behind the screen. This means there is a layer of studs and drywall between the seating and the sub. There is a hole cut out in the drywall for some of the sub sound to get through, but it isn't very large. (It's about 1 or 2 square feet). (This hole is in addition to the holes cut for center, left and right speakers.)

I'm thinking I will just go with 7.1 for now and see where that gets me. Then in a couple of years we'll see what the 9.2 technology is costing. 

Agreed. I'm trying to learn what I need to know to make sure this doesn't happen. Still a little unclear though. So what is a "full pre-out" ? Basically an un-amplified signal? What is the difference between a "pre-out" and a "full pre-out"? Are most decent receivers able to be told which channels should be pre-outs and which should be amped?

 What is a "down firing" sub? What is a "front firing" sub?

 Nevermind, I think I figured this one out. (The speaker faces the floor in a "down firing" sub.... right? Correct if I'm wrong please.)

 Hm. What if I ran them in series? That would double impedance to 16 ohms, right? Then, the reciever I'm looking at getting ( http://www.pioneerelectronics.com/PUSA/Products/HomeEntertainment/AV-Receivers/PioneerReceivers/ci.VSX-1019AH-K.Kuro ) could probably handle it... I guess. Is there a downside to doing it in series?

I googled wiring speakers in series and basically what I understand now is it's a really bad idea. I think I'll have to either pay up $1000 for that 9.2 receiver, or just let one set of speakers just be unused. (Or find an amp that supports 4ohm loads... but a quick search gives me the idea that such a receiver would cost a lot anyway so I may as well just pony up for the 9.2 channel receiver anyway)... Unless anyone can point me at a $500 or less receiver that does support 4ohm loads.....

OK I figured out what "full" pre-outs means... basically having a pre-out for all of the channels. .. 

Here's what I'm thinking. ... If I set up 7.1 speakers on the amped outs, then also hook up the extra two speakers to a separate amp that is only hooked up to two of the pre-outs, then I would have to use separate volume controls, is this right? This is the question I've been looking to find an answer for this whole time. What I think I've finally found out is this: I either use a separate amp with full pre-outs from the receiver, or use the amped outs, but never both, unless I want to start using two different volume controls. Ie, using the amped outs and the pre-outs at the same time requires that I use two volume controls.. Somebody please let me know if this is correct.

Sorry for the n00b questions, I'm trying to figure all this audio stuff out.

Thanks.

Thanks for the great info, everybody. 

I'm not going to mount wall speakers because I've just bought the speakers for the holes.

I've decided I'm going to get the Yamaha RX-V655BL. I know this will be frowned upon, but I'm going to wire up the first set of side ceiling speakers (the ones closest to the screen) as the "presence" speakers (they are in the ceiling, after all) and the second set of side ceiling speakers (the ones next to the rear surrounds) as the "side" channels. If I don't like it that way, then I'll try what was mentioned before, namely, wiring the first set as the sides and leaving the second set as dead speakers.

The Yamaha receiver is labeled as 7.2 but the manual specifies it can used as 9.2 if you use presence speakers. So this is the cheaper "9.2" solution I've been looking for.

Thanks! ... but I have some work ahead of me installing these speakers (the front, center, right holes are much larger than the speakers so I'm going to have to figure out something.... )