Sonos ARC optimal DD5.1 configuration

Hi everyone,

I recently bought a Sonos ARC, wich supports DD5.1 but i am having trouble getting the DolbyDigital 5.1 output in to the Sonos.

The sonos app, shows what kind of sound it is getting, and I am a bit lost with the plenty of options, I’ve been trying them all (passthrough on and off, setting different channels, etc.)

To test I have been using a file in a high speed USB:

the same file when i put it in my iMac Plex Server I am able to see it in the build in PLEX app in the TV (LG 47LB700V ) it outputs DD5.1 according to the SONOS app.

there are so many variables in the AUDIO configuration, and I have been reading all the info in google about it but no luck, sometimes i get no central audio, the only way to hear it properly is using 2.0 channels but that is a waste of such system as the sonos ARC


My question is, can somebody tell me which would be the ideal software setup configuration for my
OSMC Raspberry Pi 3 / Sonos ARC to exploit their capacities better ?

in the AUDIO configuration now (no dialogue unless i put 2 channels)

Channels: 7.1
Output configuration: Best match
MAintaing original volume: off
Stereo upmix: off
include LFE: 100
Resample quality: GPU Accelerated

Passthrough: OFF
Dolby Digital AC3: on
Dolbi Digital Plus E-AC3: on
DTS capable: off

To get a better understanding of the problem you are experiencing we need more information from you. The best way to get this information is for you to upload logs that demonstrate your problem (playing something but no central audio). You can learn more about how to submit a useful support request here.

Depending on the used skin you have to set the settings-level to standard or higher, in summary:

  • enable debug logging at settings->system->logging

  • reboot the OSMC device twice(!)

  • reproduce the issue

  • upload the log set (all configs and logs!) either using the Log Uploader method within the My OSMC menu in the GUI or the ssh method invoking command grab-logs -A

  • publish the provided URL from the log set upload, here

Thanks for your understanding.

OSMC skin screenshot:

Also describe with some words the cabling and used ports among the Sonos ARC, your TV and the OSMC device.

Do you mean you’ve read all this? Audio hardware and software configuration

passthrough should be ON. Channels depends on whether the Pi is connected directly to the Sonos (better - 7.1 is OK) or to your TV (probably need to set 2.0 and AC-3 transcode)

Update: I see the Arc doesn’t have HDMI in and the LG doesn’t do eARC. You do therefore need to set channels to 2.0 and engage ac-3 transcode.

Thanks; yes i did read that,

but its a bit confusing since none of the options really apply to sonos.

sonos ARC (and Beam) have only one HDMI, if I connect RPi to the sonos, how do i suppose to get image on the TV set? (Sorry just saw your update…)

I did try your suggestion Passthrough on with AC3 on on 2 channels but still no luck.

thanks so much

wow, thanks so much for the speed of your response.

I managed to fix it, I will explain.

I think i found a bug or something, because the option to enable AC3 transcoding, was grayed all the time. Until I did this:

I went to the web interface and set the passtrough on from there, turning on the Dolby Digital option too, the transcoding AC3 doesnt even appear there, ever since I did that on the OSMC menu the options for passthrough dissapeared, only appearing an announcement saying “Audio Passthrough”.

I did reset the settings on OSMC and voila the option to AC3 transcoding appeared again.

NOW IT IS WORKING with @grahamh suggested setup:

Channels: 2

Passthrough: ON
Dolby Digital capable receiver: ON
enable digital Dolby Transcoding: ON

I noticed a slight offset of the audio

the SONOS app now shows it is on DD5.1 and the sound is really great!

thanks so much!

to leave the whole case:
i will describe the setup

Raspberry Pi 3 ===> TV HDMI 3
Sonos Arc =======> TV HDMI 1 (arc)

There is no bug. The option is greyed out unless you have it set as 2 channels, passthrough enabled, and AC3 checked because these are the only settings in which transcoding will happen. Using another method to enable the transcoding option absent the other settings does not actually enable transcoding.

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Here is the log dump


I tried so many combinations that i can’t remember now how I didn’t came to this option before.


Enable Dolby Digital (AC3) transcoding: false

This should be enabled

Number of channels: 5.1 ===> Default: 2.0

This should be 2 for your setup

Output configuration: Optimized

This should be “best match”

Sync playback to display: true

This should be false

With the settings you have now AC3 soundtracks should play fine but you’ll likely have a issues with other sound formats unless you fix your settings.

thanks @darwindesign

thanks for the tip on “best match” instead of optimised,

another question is it good to have harware accelerated ?

I solved it already, I just put the dump to have the whole documentation.

Unless you have a compatibility issue with an add-on or playing some odd format then the default hardware acceleration options are optimal.

Well you still had.

In your last shared logs.