Why not use mains as centers

>OK, tried the "phantom" center yesterday, and I hate to say this, but it didn't sound good at all. Very hollow sounding, I tried some other setting changes, but just turning the center on again was a huge improvment.

You probably have main speaker / room interface problems, most likely stemming from speaker placement relative to the walls (four feet off the front wall and a few feet to side walls is a nice place to start) and large objects (like a one-piece television; upgrading to front projection is in the top 3 things I've ever done for better audio performance).

A receiver with Audyssey equalization may be a reasonable work around for the problem.

You might get a bass boost at low frequencies with a phantom center (power response sums 6dB over a single speaker's output versus 3db at higher frequencies) although otherwise there shouldn't be a difference for listeners seated dead center between a phantom image and center channel.

I have a receiver with Audessey (Denon 3808ci), and I have spent considerable time with main speaker placement of my Maggie 3.6's, so I'm going to say no, to the problems you bring up. It just sounds better with a center channel.

Johnmcelfresh,

I have often stuggled with the concept of the Center Channel. I have never been able to even imagine a center that could match up to my MonitorAudio Studio 20's and they image absolutely perfect. Recently i put in a small theater room for the family in the basement. I went with an old pair of NHT 2.0 that i had, and a Outlaw 1050 processor/amp. I have a pair of BG in-ceiling ribbons for the rears. At this point its a 4.0 system--no center, no sub. I just didnt get that far yet. However, after 2 weeks of listing to this 4.0 system i'm astonished at how incredible the 360 degree sound field is. Its better than my own system upstairs (Monitor Audio studio 20, MA 800 center, MA Gold in-ceiling, Rotel proc, Adcom power all around).

I had a hunch that the center was a problem. I did a little research and found tha the center channel is sort of meant only for theaters. WAY back, a long time ago theaters only had a center (mono). When they added 'stereo' in the 70's or so, they kept the center because it was there, AND because they needed even volume distribution over the 100' wide theater, addressing issues of people sitting way left or way right. This mono center channel insured the producer that the 'voice track' was at least evenly heard by the whole house. The .1 (sub) was added to expand the low bandwidth production that may not have been specd well in the old center, and LR mains.

None of these issues are present in my home surround system--or anyones for that matter. So i'm thinking that an audiophile 4.0 system will ALWAYS outperform a 5.1, or 7.1... The NHT's are rated down to 25 hz which is quite good, but it wouldnt hurt to have a sub in the system. So, in this application a 4.1 isnt a bad idea. However thats ONLY because the mains are a little lacking. Their big daddy, the NHT 3.3's would likely NOT need a sub.

Ny thoughts, comments?

"OK, tried the "phantom" center yesterday, and I hate to say this, but it didn't sound good at all. Very hollow sounding, I tried some other setting changes, but just turning the center on again was a huge improvement."

OK, for the record, to all the newbies, novices, and otherwise lesser experienced among us, the reality here is likely that there are many variables that effect the performance and results of a system. Simply changing one variable does not tell the whole story. For instance, there's a very very good possibility, in this situation, that the mains are likely located in a position in the room - relative to the seating area(s) - where there's a hole in the frequency response of the main left/right speaker setup. Also, there may be crossover issues, phase, etc.
Acoustics and system set up play such a huge part in the equation, that it all must be taken in context, when evalutating, trouble-shooting, and tweaking a system.
I would venture that there likely was not any care in setting up most of the system in regards to system response, initially here. So, to assume from the above statement that no center here is "not workable", is presumptuous. For informational purposes, anyway.
It is very very workable to PROPERLY setup a 2.0 or 2.1 system (allthough this is usually more effective dynamically, overall), sans the center. Not to say you should go without a center. But it can be done well, if properly considered and executed.
Thought I'd put my two cents in here...

IMO having the same exact speaker model on all channels would be the best choice. Yet I understand that doing this is probably not practical for most setups. Mains should be good over the full range, not just for mids.

My center channel (B&W) sounds very different (much worse) than my mains, yet they are both in the DM6xx family and have similar drivers. I just removed the center channel completely and told my Yamaha that there was none, and to send the signal to the mains.

I am currently in the process of setting up the room acoustics (traps, speaker positioning, etc.) so I'm not ready for a final verdict. At this point, it sounds different, not better nor worse.

I've recently read "Get Better Sound" my Jim Smith, and it discusses this topic and other related issues very well.