Originally Posted by 2dflyer
In attempting to argue for larger vs smaller center my wife asked a question this newbie was ill prepared to answer.
How can the center channel speaker be the most important speaker in a HT set up if phantom is a viable alternative?
Does it have to do with the mains imaging / proximity to each other ie 2 ch sound stage / imaging is a good indicator of phantom center performance?
Try to establish credibility with the wife and not doing such a great job
As others have noted, a phantom center can work okay if one is positioned halfway between the right and left speakers. If one is off to one side, then one will tend to hear the speaker that is closer to one more than the other speaker, and so the "phantom" center will be moved toward that side (for that listener) and not be centrally located. So that sounds that should be centrally located will not be.
The ideal is identical speakers for the front three channels (movie theaters do it that way), and although many seem to think that it can only be done with a front projector and an acoustically transparent screen (as is done in movie theaters), I have done it with a flat panel TV. I use identical bookshelf speakers for all non-subwoofer channels (because I use subwoofers anyway, it seemed pointless to buy speakers that could go deeper when the subwoofers are perfectly capable of handling everything below 80Hz; my bookshelf speakers are rated 50-40kHz +/-3dB and I use an 80Hz crossover). The three front speakers are mounted at almost exactly the same height, at about the recommended height for them, with my TV just barely above the center speaker.
Now, to do it that way, I first selected my speakers, and then selected the furniture for the TV and speakers (if I had not been renting, I would have just mounted the TV on the wall, and used an ordinary speaker stand for the center channel, which would have been easier to find than what I have). Many people buy a piece of furniture first, and then try to find a speaker that fits the furniture. To me, that is a backwards way of doing things, like buying speaker stands and then looking for speakers to fit them. It means that they typically are compromising the sound, as they generally have a different speaker in the center, so that when a sound pans across the front, it changes not just because of the location, but also because the different speaker sounds different. Even if it is supposedly "voice matched," it typically will sound different (if you would not use one of them for your right channel along with whatever you are using for your left channel, then, by your standards, they do not really match). And it is usually worse than just a different speaker; it commonly is an inferior speaker. This explains why there are so many people who prefer phantom centers, because they don't like having a mismatched set of speakers across the front. I don't recall ever encountering anyone who preferred a phantom center over having three identical speakers across the front. Usually, they have tried the supposedly "voice matched" center speaker for their right and left speakers, and found it not a satisfactory match for the right and left speakers.
Others have said that the center is only important for movies. I disagree. I have some old "RCA Living Stereo" SACDs that are three channel, and the center is a good thing for music, when it has been recorded that way. But with 2 channel sources of music, I play it back with the right and left (and subwoofers) only. I have never liked artificially added channels to music; though it sometimes can sound good with an added sense of spaciousness, sometimes it sounds very wrong, since it is sending sounds to places that were not intended in the original recording, and both can occur in the same piece of music. But you should choose regarding that for yourself, as it is a matter of taste.
I also disagree with the claim that the center channel is the most important. I would much rather have just a right and left front speaker than any two other places, even with movies. But I do think that if I am going to have one, I will have it right. I used to have a "voice matched" surround system, with the front right and left speakers different from the center and different from the surrounds, and I will never go back to that. Identical speakers in all channels (except subwoofers, obviously) is the only way I will ever have a surround system. With my system, when a sound pans from one channel to another, the only change in sound is due to the different location, and not due to a different kind of speaker producing the sound. You, of course, are free to choose as you please regarding such things.