Windows not using rear speakers

My audio output connection is Nvidia GPU HDMI to AV receiver. My current speaker setup in the AV receiver is 7.2.0.

This shows in Sound Playback as
AV Receiver
NVIDIA High Definition Audio

I have tried 7.1, Dolby, and DTS. In all of those RL and RR are actually output through SL and SR respectively so my rear speakers are not being used. Any ideas how to fix this?

Might check your configuration in the Windows Sound configuration tool. In the Run dialog box type mmsys.cpl



Select your speaker system, then Configure. Does the mode you're looking for show up on this list?



Selecting Next will show you what speakers your system detects

When I go to Speaker Setup and choose 7.1 Surround I do check all 4 of the Optional speakers listed. However, when I click RL to test it for example the sound actually comes out of SL.

This turned out to be an AV receiver issue. When I turned on certain speakers it was disabling my RL and RR.