Arc & Dolby TrueHD: Sonos System Info still displays when receiving?

  • 21 September 2021
  • 3 replies

Userlevel 1

Hi everyone. Hoping you can clear something up for me. When I first received and set up my Arc last Summer, I remember that the Sonos System Info (under About my System) would differentiate between the two types of Dolby Atmos audio signal received: DD+ or Dolby True HD.

Having established that my Arc was capable of receiving both types of Dolby Atmos signal (depending on source, of course), I pretty much stopped paying attention (just so long as the magic 'Dolby Atmos' lights up on the app, I'm happy.

I've been playing with my set up again, however, and even sources that I know to be TrueHD rather than DD+ display simply and only as DD+.

Has something changed on the software end? Has anyone else noticed something similar? I'm running the latest version of the S2 app and software, 13.2.2. Nothing has changed on the hardware side (although I'm acutely aware how finickity these audio settings and set ups can be).

If anyone could clear this up for me, I'd appreciate it. Cheers.


Best answer by jonnym75 21 September 2021, 16:59

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3 replies

Userlevel 7

If you are playing a Dolby TrueHD audio source, the Sonos app should display “Dolby TrueHD” or “Dolby Atmos (TrueHD)”. What is the source you are playing? A Blu-ray or UHD disc? Do you have a TV equipped with HDMI eARC?

Userlevel 1

Hi. TV is a Sony 65" AF9 connected to the Sonos Arc via eARC. Source is a Nvidia Shield Pro playing Dolby Atmos trailers, including at least one I know to be Dolby TrueHD (rather than Dolby Atmos DD+).


The reason for my question is that several months ago, the app would show it was playing Dolby TrueHD when playing this file. Now it shows Dolby Atmos (DD+). None of my hardware has changed - just can't figure out why I'm no longer getting Dolby TrueHD.


In the grand scheme of things, this is a minor annoyance. It just bugs the hell out of me!

Userlevel 1

Hurrah. Fixed!

What I hadn't realised is that the Arc can receive Dolby Atmos (DD+) through an HDMI-ARC connection, while Dolby TrueHD requires eARC.


Short version: for some reason, the aARC setting on my AF9 had decided to turn itself off. Because I was still getting Dolby Atmos (DD+), I never thought to check. Re-enabled and, bingo, I'm back to getting Dolby TrueHD. Happy days!