I'd think this system would sound at least pretty good in 2-channel. I looked through the 1066 manual and it looks like the stereo setting should be a pure, unadulterated signal. What's you're 2-channel source component and is it hooked up to analog or digital input on the 1066?
It's worth taking some time to peruse the manual just to see what settings might be affecting sound. Although I don't think they'd impact the stereo setting, things like if front speakers are set to small or large, is neo 6 in cinema or music mode, etc. Unfortunately the devil is often in the details when it comes to stuff like this, especially when you have no idea how the former owner had things set up.
It's worth taking some time to peruse the manual just to see what settings might be affecting sound. Although I don't think they'd impact the stereo setting, things like if front speakers are set to small or large, is neo 6 in cinema or music mode, etc. Unfortunately the devil is often in the details when it comes to stuff like this, especially when you have no idea how the former owner had things set up.