Originally Posted by Dave3000
If I intend to use optical or HDMI ARC from the TV to the receiver and the Apple TV 4k is connected to the TV using an HDMI cable and the TV can only passthrough PCM 2.0 or Dolby Digital 5.1 through optical or HDMI ARC, would Dolby Digital 5.1 be the best audio setting in the Apple TV 4k in this case? Also in this case only 2 front speakers are connected to the receiver and the receiver can decode Dolby Digital 5.1 and output it to the 2 speakers without discarding the LFE channel as it will be mixed into the 2 channels. I only use Netflix and iTunes on my Apple TV 4k, so lossless audio is not required.
Generally speaking, the higher the bandwidth audio signal you can send to your AVR, regardless of # of speakers your system has, the better off you are. I would choose DD 5.1 instead of PCM 2.0 in your setup.
Here is my supporting test:
- My HT setup: "only" 5.2 speakers
- test case movie: Thor Ragnarok
- Netflix streaming via ATV4k: Dolby Digital 5.1 (compressed audio). Letting ATV choose 'best audio' I only get PCM 2.0...so I force it to DD 5.1
- BluRay physical disc: Dolby True HD 7.1 (uncompressed audio)
Despite not having a 7.1 setup, watching the movie on BluRay disc offered tremendously better HT experience than streaming: the explosions, the depth of voices, the entire spatial and movie experience was kicked up 5 notches. No contest. The reasoning is that the BluRay audio codec was an uncompressed signal
So if given the chance, I would always watch something on disc vs. just streaming it, and if I have to stream, I try to send my pre/pro the best/highest signal possible.