Will a different center speaker help?

[JoachimStrobel]

Get the same speaker as your main speaker as pair and place them on stands on the floor slightly in front of your rack and run them off a bridged amp. The center speaker should always be the same as the main one, all these special centers that are suppose to sound similar to their main brothers are not the real thing.

 

[rnd]

But still the stereo mode gives me much more cinema feeling. The sound in stereo mode has more headroom is crispier and is more room filling.

As a complete shot in the dark, try setting the center channel at +3 dB relative to L/R. See if that makes it better, or if that makes it worse.

What is your source material? Is it stereo 2.0/2.1 or is it 5.1? If you have the on screen display active then you can check the input signal via the info button on the remote. (Otherwise it is shown on the front panel).

+1 agree, very worthwhile to check