With stereo sources you shouldn't have the center working unless you are deliberately picking to use it by having a theater processing mode active. Personally I like the Neo6 music mode, but don't really use it.
Who turns center off when listening to music
Regarding 3.1 systems. When listening to music; Who deactivates the center channel via the processor?
And with surround systems who goes back to 2.1 when listening to music. Do any of the processors have presets you can you for this?