Sonos Arc with Nvidia Shield for TrueHD Atmos via media server

I think there’s a good chance it work.  For whatever reason, it’s not uncommon for TVs to have different audio capabilities for streaming sources (through internal smart apps) and from HDMI input sources.  It makes sense in that 99% of streaming sources will not be TrueHD, but DD+ since that’s what streaming services use.  TrueHD is almost always going to be off discs in an external disc player.  There that are going to stream TrueHD like you, but even they are likely to directly connect their media player via HDMI, rather than stream through a local server.

A bit more forum surfing reveals this thread which does seem to confirm that the in-built LG TV apps will not process TrueHD and also suggests that a separate media player (such as a Shield) will work:

https://www.reddit.com/r/sonos/comments/h7iq8c/lg_c9cx_truehd_and_sonos_arc/

No because my PC is upstairs in the study and my TV is downstairs in the living room, so I’m using powerline adaptors and ethernet cables to stream from the PC to the TV. It works fine. WiFi also works but sometimes causes stutter due to the size of the movie file data stream, hence the wired alternative.

You also aren’t tied to down to a single TV, or even to TV in your home.  At least that’s the case with Plex. 

In the same shoes as the OP

LG CX and Sonos Arc 

When I try stream Dolby Atmos demo TrueHD 7.1 the Emby degrades it to AC3.

When directly connecting USB to TV it says audio not supported and then the video stutters and what not… 

But when I play witcher series on netflix i get dolby atmos and dolby vision, whole package.

I dont understand. Losing my head over this...

You need a nvidia shield as the lg cx does not play TrueHD 7.1.

Hi Bornstrong,

Streaming services (Netflix / Prime) use a lossy (dumbed down / lower bitrate) form of dolby Atmos, which is basically DDP or DD+ (dolby digital +) with Atmos metadata. TrueHD is essentially a lossless “format” and it cannot be streamed (currently) from say a PC, NAS or an external HDD or any “player” through WiFi or ethernet only through BluRay players connected directly to a compatible TV - anyone, please correct me if I’m wrong, but so far I couldn’t find any examples. The catch is that you need to pass TrueHD Atmos through a 2.0+ HDMI attached to an Nvidia Shield, which can “pass through” the lossless Atmos to the LG CX, which then (through the eARC) passes this through to Sonos ARC, which can play it.

Going through several forums, this is not always problem free and when you want to go “above and beyond” to have a lossless Dolby Vision  - profile 7 or 8 - as well then things get even more complicated (formats like MKV, mp4 starts to matter so as MEL /FEL coding etc.)

In a nutshell, you will need a Nvida Shield (2019 pro) to play TrueHD Atmos on your ARC.

How to set up: Sonos Arc→(through eARC) LG Cx → Nvidia Shield (through one of the 4K HDMIs, any of the remaining 3) running Plex or some other media server.

Does it have to be an nivdia shield or will a Roku Ultra 2020 or an Apple TV 4k do this as well? Thanks.

@rishey A Roku Ultra or Apple TV does not support Dolby TrueHD audio. 

I was under the impression that the MAT used by Apple’s own apps carried a TrueHD signal. Which may not be the case by other apps, such as Netflix, etc.

Here are the audio formats supported by the Apple TV 4K from Apple’s website:

HE-AAC (V1), AAC (up to 320 Kbps), protected AAC (from iTunes Store), MP3 (up to 320 Kbps), MP3 VBR, Apple Lossless, FLAC, AIFF, and WAV; AC-3 (Dolby Digital 5.1), E-AC-3 (Dolby Digital Plus 7.1 surround sound), and Dolby Atmos