Bruno, just to confirm what others have said, when you set the receiver to show no center speaker, the center channel is automatically sent equally to the two mains, giving a "phantom" center channel; no other special setting is needed. As Alan and others have pointed out in the past, the dialog in the center channel in some DVDs isn't mixed high enough for easy intelligibility. One of the advantages of a separate center speaker is that its level can independently be bumped up a few dB to help with dialog. This of course isn't possible with the mains handling everything and there's no simple solution for those DVDs which have this problem.
