I have some files with AAC audio. The problem is that my soundbar doesn’t work with that content so the audio ends up as stereo and the overall audio quality is poor. With the 4K Fire Stick I was able to force Plex to transcode AAC to AC3 by changing audio passthrough to “Optical” and change Optical Encodings setting to AC3. This seemed to work with the soundbar and I was able to confirm that I’d get true surround sound.

Based on some limited research it looks like this is something that happens with some Android TV devices and Plex. Changing the setting has no effect within the Plex app. Is that the case here? Any solutions to this? I really don’t want to go through the hassle of converting all my old content to AC3 or using the Fire Stick with this TV.

Update: Switching to an older version of Plex solved the issue of converting AAC to AC3. However, it looks like AAC content is not supported on the Onn box. Someone pointed this out and I tested it out with another TV that has an A/V receiver that works with AAC content. Even if you have audio equipment that can handle AAC, you will still get stereo sound because the box itself doesn't support AAC. Doing the trick I mentioned with optical passthrough and forcing conversion of AAC to AC3 will allow multi channel audio, but this really shouldn't be necessary as other streaming devices would be capable of outputting multi channel AAC on their own. You'd only want to do that method if you have audio equipment that can't work with AAC like my soundbar on the secondary TV I have. Just a heads up for anyone who has a lot of media with AAC audio.