Apparently it only supports Dolby Digital. I know for a fact is doesn't support DTS, but I knew that when I bought it. I guess I assumed it supported 5.1 PCM and DD+, but was wrong. I have the Surround 3's and I can only get 5.1 when using Netflix, Prime or HBO max. I have tried just about every hook up and TV settings I can, but still cannot get 5.1 though certain apps even when the broadcast is in 4K. I use the Dish Anywhere app a lot and can only get 2.0 stereo when using. I can get sound to run through the Surround 3's when I set the TV audio settings to pass through or PCM, but it is just in stereo, not 5.1. It's not the TV as I have auto detect, auto pass through, DD, DD+ and DTS setting on the audio out settings. I tried them all. I can get 5.1 / 7.1 on all apps including the Dish Anywhere app through Firestick when using my tradition set up, so I know it is not the signal. Really disappointing. I will say the sound and clarity of the bar and surrounds are great, but if it only decodes DD and stereo then what the use. Very disappointed. Maybe they will come out with a firmware update to support more audio formats. I pre-ordered the Cinema 1200 to get Atmos and was going to move this to the bedroom, but I am thinking I am going to cancel now.