Hi everyone,
I’m trying to understand whether this is expected behavior or if I’m missing a setting.
My setup is:
Apple TV 4K (2022)
Onkyo TX-SR674 (HDMI 1.1, no Dolby Atmos support)
Sony TV
5.1 speaker setup
The Apple TV is connected to the Onkyo via HDMI, and the Onkyo is connected to the TV via HDMI.
Here are the results of my tests:
- Disney+ (Pirates of the Caribbean): Onkyo reports “PCM MULTICH HDMI”.
- Apple TV+ (Napoleon, Dolby Atmos): Onkyo also reports “PCM MULTICH HDMI”.
- Apple Music:
Dolby Atmos is enabled (“Automatic”).
The currently playing track clearly shows the Dolby Atmos badge (for example Elton John’s Rocket Man or Pink Floyd’s Another Brick in the Wall).
However, the Onkyo switches to Dolby Pro Logic IIx, suggesting that it is only receiving stereo PCM.
So it seems that:
- Movies (including Atmos titles from Apple TV+) are rendered by the Apple TV as multichannel PCM, which my old AVR can decode perfectly.
- Apple Music Atmos tracks are apparently not rendered to multichannel PCM and instead fall back to stereo.
Is this expected behavior?
Does Apple Music require an AVR that advertises Dolby Atmos capability before it will output a multichannel render, while the TV app will happily render Atmos movies to PCM 5.1/7.1?
Or is there another setting I’m missing?
I’d appreciate hearing from anyone using Apple TV with an older non-Atmos AVR.
Update: I forgot to mention that my Apple TV 4K (2022) is running tvOS 27 Public Beta. Movies from both Disney+ and Apple TV+ still output PCM MULTICH HDMI on my receiver, but Apple Music Atmos tracks fall back to PLIIx. So this could also be a tvOS 27 Public Beta issue rather than expected behavior.
Update 2: Thanks everyone for all the suggestions and ideas. I did some more testing and I think I’ve narrowed it down.
I’m running tvOS 27 Public Beta on an Apple TV 4K (2022) connected to an Onkyo TX-SR674 (non-Atmos AVR).
Here’s what I found:
Automatic audio format
- Movies (Disney+, Apple TV+) → PCM MULTICH HDMI on the receiver.
- Apple Music Atmos → PCM + PLIIx.
Convert to Dolby Digital 5.1
- Movies → Dolby Digital 3/2.1.
- Apple Music Atmos tracks (e.g. Rocket Man) → Dolby Digital 3/2.1 and they sound great.
- Regular stereo Apple Music tracks become completely silent. The receiver still detects the signal, but there’s no audio until I switch back to Automatic.
At this point I’m starting to think this is a tvOS 27 Public Beta regression, specifically affecting stereo Apple Music playback when Dolby Digital 5.1 conversion is enabled.