Bad news: 2 channel audio can't be converted or 'decoded' to provide 5.1. The original recording and source must be multi-channel. There are different listening modes on your unit. There's one called "AllCh Stereo", where the audio is played through the surround speakers. This is not 'surround sound' but simply L+R sent to the surround speakers. Any other mode that sends signals to your surrounds will be a simulation, possibly like the mode "Studio-Mix" for example. There's no mention if any signal is output to the center channel. Experiment to find something that may be acceptable.