Why not use mains as centers

Kal,

You are quite correct. Speaker arrays (same drivers outputting same frequencies) are best avoided except in the bottom two octaves (assuming one cherishes precision). You get lobes in response as well as comb filtering of certain frequencies which makes the audible response much more variable than a point source.

In specific, horizontal speaker arrays are fundamentally flawed and that is why you see so few of them used for stereo or main channel speakers.

Absolutely agree. I have no ATC center channel. There is a reason and it is not budget. There is also a reason that studios use the same speaker for center channel as they do for the other channels. Also studios align the speakers vertically (midrange and tweeter must be at the same height as L and R). The whole HT horizontal home center channel thing is a compromise for off axis listeners - they benefit but overall everybody loses a bit from this configuration. Obviously the TV screen makes this comprise necessary, however, for those who rarely watch movies with a crowd their is a compromise which is better IMHO: phantom center!

So,for home theater I sould try to find the best matched center as opposed to using two speakers emitting the same signal on the sides of the screen?

If you have excellent Main Right and Left speakers that image well and are dynamic and you do not invite a crowd regularly to the house (you and one significant other mostly) then I'd recommend using Phantom and use the money saved to buy a better amp or better subwoofer or better TV or better L and R mains.

If you find yourself needing a center channel with just yourself in the sweetspot listening then you should replace your main speakers - they probably don't have teh dynamic range needed for movie soundtracks - typical manifestation of this problem is either:

1. It is too loud and boomy when you can hear dialogue prooperly

2. You can't hear dialogue properly at modest levels.

=> a center channel will indeed help fix the dialogue problem but it is not adressing the root cause. Contrary to popular opinion, movie soundtracks often have much greater dynamic range than music - they therefore require very good speakers to do a decent job of imitating what you actually experience in a good cinema theater.

Oilmanmojo,

That is the ideal way to do it - you need the right kind of screen for this but this is the perfect way.