I have 3 Rokus, 3 different models. The only change I am making is to swap out the Rokus, otherwise ALL is the same including the source streams.

Source is 5.1 surround sound, output is capable of handling surround sound and is connected via optical cable from the TV. Roku connected to TV via HDMI.

1) Roku Express 3900R - No multi channel sound detected by receiver. Audio in Roku settings is set to Dolby.

2) Roku Ultra - No multi channel sound detected by receiver. Audio in Roku settings is set to Dolby.

3) Roku 2 - 4210R - This is the only Roku I can get to emit 5.1 surround sound to the receiver. Unfortunately this model doesn't have private listening, so I can't keep it in the location I need the 5.1 surround sound.

So the setups is ROKU<HDMI>TV<OPTICAL>RECEIVER -> Speakers

DD+ does not transmit over Optical to your receiver, that is most likely the reason you do not have 5.1 (depending on source content) at the receiver.  Now why the Roku2 does?  I want to say I read somewhere long ago that the Roku2 converted DD+ to DD which would then pass along your chain.  I could be wrong about this though.

I read that turning on "Night Listening" can cause this. I went to turn it off as I definitely had it enabled on the Ultra. However the menu option no longer exists for Night Listening? I thought I was going crazy, so I looked it up.. yep.... its supposed to be in the Settings, Audio - but its not there any more?? I have only HDMI, Menu Volume, and Audio Mode (Set to Dolby DTS). It doesnt match the screenshots online....

Update:
Was able to turn it off by playing a video and using the * key. Now the Ultra sends 5.1 sound properly. Second update.. The Express had night mode on as well... turned it off but have to move it to retest it. I expect this will fix it.

I think maybe this should be well documented or even a warning when turning night listening on....

twiceover wrote:

So the setups is ROKU<HDMI>TV<OPTICAL>RECEIVER -> Speakers

DD+ does not transmit over Optical to your receiver, that is most likely the reason you do not have 5.1 (depending on source content) at the receiver.  Now why the Roku2 does?  I want to say I read somewhere long ago that the Roku2 converted DD+ to DD which would then pass along your chain.  I could be wrong about this though.

Receiver isn't DD+, only DD. Its an old receiver but quality. I had 2 newer ones but both a Sony and Onkyo died within 1 year so I went used but much higher end. Its already outlived any newer receiver.

Also the optical is from my TV to receiver, Roku is sending audio to TV via HDMI.

The Rokus do pass through. The problem was night listening... when its on it decodes and reencodes.. turning that off fixes the 5.1 issue. Both on this forum and in Google this is a common issue, but few have resolved or learned why. I was lucky to find something in a reddit thread.

Yeah, Roku has never made it clear to many users that Night Mode, or any other volume modification mode, switches the output to 2 channel stereo. It's out there, but not well publicized.