I have a Roku 3 connected to my 975 via HDMI. The HDMI setting is DD+. DTS auto. But I only get 2-channel sound. I get 5.1 from Amazon Prime and other sources. I also get 5.1 if I use my Oppo BDP 103 to run Netflix through the 975.

I have seen posts elsewhere noting that Netflix on Roku uses only DD+, not DD.

The Roku firmware is up to date.

Anyone having/had similar problems.

Nope. I get full surround on Netflix stuff. I don't remember how I have it set up and I'm at work so can't look for you. I think Netflix might have it's own settings in the app. You may want to check there to verify its output.

When I looked more closely, instead of relying on memory, I found that the box is a Roku 2XD, which used to work oK with Netflix. Rather than waste time trying to figure out what's wrong with a 4- or 5-year-old box I ordered a new Roku Ultra Amazon is selling for $86.