The Roku Ultra had a separate optical digital audio output, but that feature was discontinued 2 or 3 years ago. They only way I know of to get a separate audio output with the current product line is to run the HDMI output through a device that can extract the audio from the HDMI signal and output it separately. https://www.amazon.com/s?k=hdmi+audio+extractor
Roku Community Streaming Expert I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well. If this post solves your problem please help others find this answer by clicking " Accept as Solution.".
Streaming Stick 4K+ 3821 | Streaming Stick+ 3810 | TCL Roku TV 43S245/C107X