jrmav,
Everyone's advice here is excellent, but I'd also point out that once you've recalibrated downwards so you have more adjustment range for the center, keep in mind that dialog intelligibility is very important, so don't feel you have to keep the center at a particular setting!
With some movies and shows, dialog is mixed too low (the director and mixer have heard the dialog a million times and know it, so sometimes they mix it too low. I hear this in cinemas sometimes.) So just nudge up the center if you can't understand the dialog. I vary my center's level adjustment depending on the movie or program. Most movies are fine, but occasionally, you have to adjust the center.
Regards,
