What soundbar do you have, Sony or Sonos?
Soundbar connects to HDMI 1. That's your ARC connection according to your TV manual. You can connect your Roku to HDMI 4.
Go to the TV settings/home menu/sound/speakers and choose "audio system".
Go to the TV settings/home menu/sound/audio out and choose fixed or variable output.
If you still get no DD at the soundbar, use an optical connection.
from the Sony manual:
When connecting a digital audio system that is compatible with “Control for HDMI” (“BRAVIA”
Sync) and Audio Return Channel (ARC) technology, connect to HDMI IN 1 with an HDMI cable. If
connecting a system that is incompatible with “Control for HDMI” or Audio Return Channel, an
additional audio connection via DIGITAL AUDIO OUT (OPTICAL) is necessary
also:
To use multi-channel audio, connect to an external audio system compatible with Dolby Digital
using an optical cable, and select [Audio System].
[Audio System] must be selected to listen to 5.1 multi-channel audio.
My apologies for the typo in my original post; I have a Sonos Beam Gen 2 sound bar.
Connections are:
Roku Ultra 4802X (hdmi) <--> (hdmi) Sony XBR-46HX929 (hdmi/arc) <--> (hdmi/arc) Sonos Beam Gen 2
As states in the original post, I can see what audio codec is in use via the Sonos iOS app, and Netflix/AmazonPrime/Hulu all output DD 5.1 just fine. It's only HBO Max that will only output Stereo PCM. In the Roku HBO MAX v54.1, all of the Atmos labeled content (Avatar Way of Water for example) should be outputting DD 5.1 if the receiving unit doesn't support Atmos (which my configuration doesn't, as it's limited to the Sony TV @ DD 5.1). However, it seems that HBO MAX will deliver Stereo PCM only, and not DD 5.1, as it should.
I have the suspicion that if I were to upgrade my TV to a newer eARC capable TV, than HBO MAX would pass-through Atmos content just fine to the Sonos Beam Gen 2, but I don't plan on upgrading my TV until this one fails on me (For it's age, even today it's a surprisingly good TV even when I compare it to the newer LCD (non-OLED) TV's at Best Buy). However, I believe HBO MAX should be outputting DD 5.1, when Atmos isn't supported. I don't really know where the problem is, however, if it's with the Roku not selecting DD 5.1, or the HBO MAX app has a bug that prevents it from correctly outputting DD 5.1 in this case.
(This is why I never upgraded to a 4802.)
I don't decode atmos, but I can confirm Avatar WoW on max plays DD 5.1 just fine at 4K60 HDR 10 with the TV audio output via optical.
Do you get atmos audio to the soundbar on any non-max channel?
Do you get DD 5.1 on any non-atmos programming on max? (max is f'd up on video, they lost 24p on the transition; maybe their atmos audio is fubar.)
(Always check that leveling and night modes are off when you see pcm.)
Have you tried the optical/HDMI adapter Sonos gave you, and used the optical out on the TV instead of ARC? That will limit you to DD 5.1, I believe, and maybe max will provide that.
from Sonos:
If your TV doesn’t have an HDMI ARC or eARC port, you'll need to use the optical adapter:
Remove the protective cap from the optical adapter, then attach the optical adapter to the HDMI cable.
Connect the optical adapter to your TV’s optical digital OUT port.
(The TV's optical adapter’s port is “D-shaped”—make sure the connector aligns correctly into the port. Inserting the adapter incorrectly may damage the cable.)
My setup can only do DD 5.1 maximum, and yes DD 5.1 is playing on the Sonos Beam from Netflix/Hulu/AmazonPrime (just not HBO MAX v54.0 build 1).
What version of the HBO MAX Roku app are you using? The latest v54.0 build 1 is not outputting DD 5.1 for me. I do recall that the previous versions were outputting DD 5.1 just fine, but I don't recall which versions worked (as I wasn't checking app versions when things worked).
