Well, this is just strange. The Vanco device has some almost English instructions re whether the green LED is to be on or off to deliver stereo. When I first installed it, the light had to be on to get sound. I was taking the analog stereo output from the Vanco.
At the client's now: the audio adjustments on the Roku don't matter. What matters is pushing the button on the Vanco so that the green LED is off. (The client only uses the Roku for Netflix so I did not set up accounts on other services or try them out.)
The instructions that came with the Vanco say this about the push button and the green LED:
Note: Only when the source supports 5.1CH output (including CD), this function is effective and it realizes through the 2.1CH/5.1CH buttons.* The product default output is 5.1CH, and LED turns on at the time. Press the button a time again, the product outputs 2CH audio and the LED turns off. If the source can only supports 2CH audio output, the “2CH/5.1CH” button will become invalid, that is, although you press “2CH/5.1CH” button, the product still outputs 2CH audio and the LED is still on.
This is clear, right? It ends up saying that if the source "can only supports 2CH audio output," the LED is still on. Well, when I set the Roku to 2 channel, the LED stays off.
I just hope it continues to work!
*There's only one button. This is a mistranslation.
