Cannot get any sound from the back surround speakers. Have spent hours reading through various posts about similar problems, testing every combination of settings, and every Roku app I have access to.
TV is TCL 55R625 using Roku streaming apps, optical output to Pioneer receiver VSX-1019AH, on which the Dolby Digital icon lights up when the TV is set to output DD. Have tried every audio setting on the TV. In Roku I've tried amazon prime, roku app, Dolby app, google play app, and multiple shows/movies in each. Nothing will produce sounds from the back speakers.
rtings.com has tested the TV will send 5.1 Dolby via optical to a receiver.
I've solved the problem by changing a surround setting on the receiver, which I suspect was not set correctly for the TV input.