Hi Terry,
It is legit, but it's especially critical for the center channel and the main left and right speakers to be quite similar. Otherwise, if a center has, for example, a somewhat "cupped" or nasal coloration (and your main speakers are free of this), then when an actor's voice moves from the center to the left or right, you'll actually notice his (or her) voice change in character, and it's very annoying. It makes the sense of space and your involvement in the movie less real.
I've found that timbral mismatches in surround speakers aren't quite as noticeable or as annoying, although I'm still aware of them. But timbral similarity in the three front channels is what really counts.
Regards,
Alan Lofft
Axiom Resident Expert
