(2021 added note that macOS Big Sur DVD Player has no Disc Setup prefs setting.) Later added Notes on Audio Hardware Setup, and Subwoofer output. Setup OS X to Output 5.1/7.1 Surround Sound via HDMI to A/V Receiver and HDTV
Mac OS X settings for 5.1/7.1 Surround Sound to HDMI A/V Receiver and HDTV