Are you prepared to properly start a Plex server?

Is there a way to force Plex to transcode particular audio-only files while playing remotely? It appears that it will transcode FLAC files to AAC if they're above a particular bitrate. e.g., stuff ...

Check the audio settings of the Roku. If it's not hooked up to a system capable of playing. 5.1, it needs to be set to stereo. What you mean by "downloaded" can make a difference too. It's set for 5.1 ...