Unless you've got your mains spread out pretty far and / or the mains don't do voice very well on their own, adding a center channel can make matters worse. If i had my HT system set up like most people do i.e. with their mains about 6.5 - 8.5 feet apart, i wouldn't bother with a center channel. Having the speakers that close together with a center speaker gives you more of a "wide mono" presentation than a R / C / L image due to the lack of separation and "colliding imagery". This might be different if using "micro" speakers in your system though, as the limited output from such a design will need as much help as it can get. Obviously, what works best is room / system dependent.
For sake of reference as to where i'm coming from, my mains are about 14' apart ( center to center ). The center channel uses identical drivers for the tweeter ( .75" dome ), upper mid ( 2" dome ) and two mid-woofers ( 8" each ) to what the mains and the rears have. The mains also have have two 12" woofers per cabinet with the surrounds having dual 10's per cabinet. Obviously, adding either of these woofers would be somewhat "overkill" for the center, especially since the center can do 35 Hz with authority as it is.
Having said all of that, i think that you'll find that it is very important to have the "voice" of the center channel speaker match that of the mains. On top of that, proper time alignment in terms of when the sound arrives at your ears from the L / C / R must also be properly dialed in. Otherwise, you end up with different parts of the audio spectrum sticking out from the various speakers AND the sound itself is not coherent since the imaging is disturbed by various arrival times.
Our brains localize sound by the differences in arrival times, frequency responses and reflections. By having different dispersion patterns, frequency responses and time coefficients, a center channel that is not well matched and properly "dialed in" can surely "shrink" your soundstage and upset the cohesiveness of the presentation compared to what you would otherwise hear with two speakers and / or three speakers that are operating properly. Sean
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For sake of reference as to where i'm coming from, my mains are about 14' apart ( center to center ). The center channel uses identical drivers for the tweeter ( .75" dome ), upper mid ( 2" dome ) and two mid-woofers ( 8" each ) to what the mains and the rears have. The mains also have have two 12" woofers per cabinet with the surrounds having dual 10's per cabinet. Obviously, adding either of these woofers would be somewhat "overkill" for the center, especially since the center can do 35 Hz with authority as it is.
Having said all of that, i think that you'll find that it is very important to have the "voice" of the center channel speaker match that of the mains. On top of that, proper time alignment in terms of when the sound arrives at your ears from the L / C / R must also be properly dialed in. Otherwise, you end up with different parts of the audio spectrum sticking out from the various speakers AND the sound itself is not coherent since the imaging is disturbed by various arrival times.
Our brains localize sound by the differences in arrival times, frequency responses and reflections. By having different dispersion patterns, frequency responses and time coefficients, a center channel that is not well matched and properly "dialed in" can surely "shrink" your soundstage and upset the cohesiveness of the presentation compared to what you would otherwise hear with two speakers and / or three speakers that are operating properly. Sean
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