Multi channel conversion



Hi all

I have a TCL attached to my Sonos sound bar. Sonos doesn't support 7.1, however, TCL does. (I think) Is there a way to tell Plex to convert 7.1 Hd to 5.1 when the TCL(Roku) Plex app plays a movie? If so, could someone point me in the right direction to remedy this. Some of my backups only contain the 7.1 track as they were done before I got my sound bar.