Audioholics did a neat setup with a Yamaha receiver, two amps and eight Axiom speakers (two center channel speakers).

http://www.audioholics.com/productreviews/loudspeakers/AxiomAudioM80tiEP600p1.php

Could this same setup be done with a 990/7700 combo without the additional amps? The two center channel speakers has me stumped.

Thanks

You could use two center channel speakers and connect them both to the same channel on the amp, but I don't know that you would really gain anything. Do you have a massive screen or something?

I have a 60" diplay. I prefer a stronger center channel presence than most in HT-mode and like the idea of placing a center channel speaker above and below the display (balanced to middle of display).
My LCD is located 13 feet away from listening sofa and center channel speaker is located about 3ft below the display (bound by cabinet configuration). I "believe" the addition of another center channel speaker would help balance the sound (coming from display and not 3 feet below) and provide a little extra punch from the center channel... just don't know how to wire to a 7-channel amp to eight speakers. A $350 speaker is a possibility for a father's day present

I would suggest staying with a single center. Having two can create more problems (cancellation, etc.) than one. The would also need to be the same ohms and have similar crossovers, etc. I would spend the dough and buy a beefy center channel. I use the Klipsch THX LCR for the center. Before going to this monster of a speaker, I always thought the center channel was drown out. The center should be the best speaker in your system in my opinion (for movies anyhow). After all, like 80% of a soundtrack comes from the center.

Good points Doug... I was hoping that by doubling up on the Axiom VP150's w/ mounting bracket on top speaker would be worth the extra $350.

Well, it is possible to wire two speakers in parallel off of one amp, but it puts an extra burden on the amp. There are actually instructions for doing this in the Model 1050's manual (it was a 6.1 receiver, but they offered a way to drive two surround back speakers off the single surround back amp channel). Here's what that manual suggests:
In the case of the 7700, there's no impedance selector to worry about - it will handle the 4 ohm load just fine. If you had a pair of low-impedance, low-efficiency speakers, you might want to grab a M2200 to drive one of them and split the pre-amp output, but the VP-150's are rated at 6 ohms and 91dB efficient so they'd probably be just fine.

From a practical standpoint, I agree with Doug that a single center is probably best if you can place it well. The VP150 is a pretty substantial center channel - can you move it to on top of the TV, or are there space restrictions there as well? If you haven't done so already, you might try aiming the center up toward the listening position. I've had to move my center off of the top of my TV (it's more than a foot above the top of the screen), and by aiming it down toward the listening position I've been able to get pretty satisfying results.

My HT has two Axiom VP-150s, one beneath the screen on a shelf and one above screen on a mounting bracket (92" screen). I did it for similar reasons saddlesore – I started with one center below the screen and had issues getting it to sound right in many circumstances. For the long-story, even before that I started with a perforated screen and a center behind it….great sound but not-so-great picture. And I’m sitting fairly close to the screen which gives less room for error. Two centers has fixed everything (pretty much, keep reading) - my virtual center is now "centered" horizontally and vertically and seems fuller in general.

My solution to get two center channels out of a 7-channel amp is to skip 7.1 and go 6.1. That way you have an extra channel for two centers. The only other way to do it in my opinion is to get another 2-channel amp and let one of the channels in your 7-channel sit idle (in that article you linked they actually used 4 channels of the receiver for surrounds and then two 2-channel amps for R,L, CT, CB for a total of 8 channels). I considered getting a 2-channel amp for the surrounds to get to 7.1...and probably will some day, but so far the single rear speaker has been working okay for me.

As for cancellation…I did need to do some tinkering on placement to get them to sound like a single speaker. My setup helps me do this in that the three primary listen positions are all in a row the same distance from the screen. So, since the top center is little farther from the ear in the vertical space, I have it little closer in the horizontal space so that the ear-to-speaker distance is the same. I tweaked the angles a bit two. I also carefully set the levels so that each center was equal but in sum equaled the other speakers. This is not much extra work than careful speaker placement and setup in general though. And I would recommend the exact same make/model of center-channel speakers. To be fair, I do have one non-primary listening position where it doesn’t sound quite right that may be the fault of the two centers canceling or something…may need to work on that one a bit or give it up.

All in all, I’d recommend two centers, more amps if desired to get to 7.1, and more patience on setup if needed – it is worth it. You can’t skimp on center on HT in my opinion, and so if you aren’t satisfied and are willing to spend some time and a few $ for another center, go for it. To save $ (like me) and not buy more amps, I’d say two centers (in my case and maybe yours) trumps 7.1 over 6.1.

The very reason for using a centre speaker is to avoid a dual-mono, phantom-imaged, comb-filtering centre channel that comes with sending the same exact information to 2 speakers. This is all the more critical because of what usually gets reproduced through the centre speaker: vocals and dialogue. The human voice is a point source (no one speakers in dual-mono) and is more realistically reproduced via a single speaker. Using 2 centre speakers defeats all the advantages of going beyond a 2-speaker front soundstage.

I am also running a 2 speaker center channel with my 990.

http://tinyurl.com/en4ml

Speakers are wired in parallel; simply piggy-backed the banana plugs from one speaker to the other. Reasons for doing this were:

1) I did not have room to put my speaker(s) vertically under the (100") screen. With 2 speakers, I maintain system symmetry with the speakers on their sides.
2) I had the spare speaker; so why not? What else was I going to do with it? ;-)

As others have stated- doing this will half the impedance seen by the amp; if you're using an 8ohm speaker, 2 speakers in parallel will present the amp with a 4ohm load. This may or may not be a problem for your amp(s). The alternative is to split the center channel source signal from the 990, and feed a stereo amp, driving the spekers in syncronous "stereo". I personally think the mono-amp, parallel speaker route is a cleaner way to go.

saddlesore,

I have 2 centers.

I have a VP150 that I tried over and under the screen but could never get the proper localization.

I bought 2 Axioms M3s for the task and love them. They run in parallel from an M200. The lower speaker is placed a little farther away to match the distance of the speaker above the screen. I also think that the M3s give you more lower frequency response than the VP150 and I like that too.

The VP150 is used as channel 6 right now, but doesn't get much use. I will probably ebay it.