@mcfc4heatons Keep the Digital Audio Out setting set to RAW and try to find a 5.1 audio source. But keep in mind that the rear surround speakers will only play the rear surround channels of the audio track which is typically the musical score, ambient and environmental sounds, or action that happens behind the camera. Most of the audio will still come from the Ray (front channels).
When listening to stereo audio, the Ray will perform an audio up-mix of the stereo signal to create a simulated surround sound. This means you’ll still hear most audio out of the front channels too, but the rear surround speakers will play what is determined to be ambient audio.
You can also adjust the Surround Audio level in the Sonos app.
Read more here:
https://support.sonos.com/s/article/3335