I have a Roku Express 4K+ connected through an HMDI port on my Denon AVR X3400H. The surround system of speakers is a 5.1 channel setup. Both the Roku and AVR have wireless connections to the Spectrum service with 100 GB speed. Only two speakers of the five in my setup work (front right and front left) when using the Roku for streaming content. I checked the Amazon Firestick, also connected to the AVR, and all speakers function. My TV is an older Samsung (from 2009). Am using a new optical audio cable from the TV's digital audio out to the TV audio-in on the AVR. Additionally, I'm running an HDMI cable from the TV HDMI 1 (DV) to the AVR monitor 1 ARC input, both of which are required to complete the audio connection from the older TV. I've done a reset of the speaker setup to the AVR and tested them to make sure sound is emitted from all of them.
Hoping someone has the answer to why only two of the speakers function using the Roku and how to fix the situation. Could be as simply as my Roku model will not support the surround sound system, but am hopefully of an answer from the Community...thanks!