What were you listening to when changing modes? If you were playing two channel music in dolby surround, it would not sound very good in a dolby surround mode without adding center spread. But, that’s another topic. What is the speaker configuration and amp assign?
Movies in both instances. More specifically, Guardians of The Galaxy in 4K on Disney +.
Speaker configuration is a 7.2 set up. L/C/R with 2 side and 2 rear surrounds. One subwoofer at the front of the room, the other at the rear.
I set all the distances on the speakers yesterday. I haven't messes with the amp assignment, EQ or dB levels yet. I'm going to play around with that tonight to see if it helps.
The only way for me to describe the difference in sound between 9 channel stereo and the Dolby modes is that the 9 channel is much louder, and much clearer. While all of the Dolby modes are dull, muddy/muffled and the volume is much much lower.
This wouldn't be a problem per se if my 2 rear surrounds were producing sound when I have it in 9 channel stereo. I'd ignore the Dolby modes altogether. But it seems to be one or the other: better sound/less speakers (9 channel) or terrible sound/more speakers (any of the Dolby modes).