If Windows 11 is not offering 5.1 surround options, follow these troubleshooting steps:
Fix: Your system is downmixing the audio. If you are using an optical Toslink cable, ensure your TV supports 5.1 pass-through over optical.
Once you have downloaded a reliable test video, follow these steps for an accurate calibration.
Moving beyond simple channel checks unlocks your system's true potential.
Look for "Audio sample files" in the Kodi Wiki to find direct links to multichannel test loops. Step-by-Step Guide: How to Properly Run Your Test
I can provide specific troubleshooting steps for your equipment.
Set to "Direct" or "Straight": Set your AV receiver to a mode that doesn't add artificial processing. You want to hear exactly what the file provides.
: You can download a complete Dolby Digital, DTS, and THX Surround Demonstration DVD as an ISO or in various video formats like MP4.
Demolandia maintains the most comprehensive collection of surround sound test files on the web, spanning over ten pages of Dolby content covering Dolby Digital 5.1, TrueHD 7.1, Atmos, and 4K Atmos. The Dolby Digital 5.1 demo trailers were engineered to exercise the characteristics of each format.