How to get 5.1 audio output

I am running windows 10 with a 5.1 speaker setup. When I configure the speakers in Windows Play back devices I can hear audio coming out of each of the individual speakers. I have Unity set to output 5.1 in Edit -> Project Settings -> Audio -> Default Speaker Mode. When I play my game I have an audio source circle the camera and its audio listener. Unfortunately I never get any audio out the back speakers.

Debug.Log(AudioSettings.driverCapabilities) outputs "Stereo" while

Debug.Log(AudioSettings.speakerMode); Debug.Log(AudioSettings.GetConfiguration().speakerMode);

outputs: "Mode5point1"

It seems my speakers work, and windows can output to them, but I can't get Unity to recognize the audio setup as 5.1

I found previous forum post suggesting that I replace a directx dll with one of their attachments, but I am not to excited about running an arbitrary from a random forum.

Any ideas on how I can get proper 5.1 audio output from Unity?