No issues here LG B9 and sonos arc with Apple TV output 5.1content as multichannel PCM 5.1

Just to update happens on my xbox series x as well, which is set to uncompressed 5.1, and sonos arc outputs as 7.1

Perhaps its an lg cx issue, I know i’m not the only one with this issue, those that have the problem please state what tv you have.

I get the 7.1 if it is set to passthrough.  It changes to 5.1 if I set the tv to auto.   This is on 2020 75 LG Nano 90 and I also just got a 55 LG OLED CX.  It was the same, so I just returned it and just now realized my Nano 90 is doing the same thing.

Yeah seen a few mention AUTO works on lg cx, but for those that want to pass full fat atmos (true hd) from say a 4k bluray player, it needs to be set as passthrough.

Certainly a strange issue/bug.

I also have the 7.1 issue. I just wanted to chime in and say that AUTO does not work to output Multichannel PCM in 5.1 on the LG CX for me. If I do AUTO, then it will only play PCM 2.0.  My settings are HDMI Input Audio Format set to Bitstream and Digital Sound Out set to Pass Through. On my PS5, I have the Audio Format set to Linear PCM. When I play games,  the About My System page in the Sonos app shows Multichannel PCM 7.1. 

Good to know, hadn't tried Auto on the cx myself, just thought someone had mentioned that works, but perhaps not then.

Hi

I have an LG OLED B7 and since the update I can now get my OPPO 203 to play pcm 5.1 when a DTS disc is in use which is great. the volume was a lot lower than when Atmos is playing. however it means I don’t need another Blu ray player.

Can anyone from Sonos please advise, this might be more of an LG CX and latest LG models issue, but your update caused it.

Thank you

I was really hoping that today’s speaker update was going to fix this.  Anyone able to see if this was addressed? The 5.1 content from Netflix through my ATV still shows Multichannel 7.1

Exactly. To be honest even if the LG OLED is passing through a 7.1 LPCM signal, the Sonos Arc should be able to downmix it to 5.1. There is no such thing as Dolby Multichannel PCM 5.1 as the Sonos reports with certain content either, so clearly the first version of LPCM support on the Sonos Arc is buggy.

I have the same issue with the Opposite 203 and my LG OLED C9. I now get 5.1 from DTS discs but the volume is so low it’s almost unwatchable. 

Really disappointing as I only bought the Arc as I knew it would eventually work with DTS content with the LPCM update but the quality of the audio this way is terrible.

@Ryan S are you guys looking into this issue? We’re glad the LPCM update is out but there are multiple reports of devices defaulting to sending 7.1 tracks to the Arc and the soundbar is unable to downmix it to 5.1. In most cases this causes missing dialogue or audio coming out from the wrong channels. On top of that the sound volume when using LPCM is really low compared to bitstream.

I could be wrong, but I think Sonos HT speakers just play what they are sent (or silence if sent something incompatible like DTS), and don’t attempt to do any downmixing or other audio processing.  

I thought the demand for multichannel LPCM came from the gamers.  I am puzzled as to why there was an expectation this would deal with the DTS issue on Blu-rays.

Is the volume low on LPCM for all scenarios?  I ask in genuine curiosity.

I get the low volume on PS5, Series X and Apple TV 4K. The latter is the most problematic one with the 7.1 issue  since there’s no way to force 5.1 through settings like the consoles can.

Hi

Well for me I got stereo from DTS blurays before the update, TV set to bitstream/passthrough and bluray player set to bitstream.

Not quite sure why you think this LPCM update was just for the gamers, I’m much happier to get multichannel pcm than stereo 2.0, just be nice if it was outputting correctly and not in 7.1.

Also all my content on my apple tv 4k box in dolby 5.1 is output as multichannel pcm 7.1.

So i’m not sure where you are coming from.

So what happens if you set your TV to output DD5.1?

I have not looked to try, I know there is an auto setting but then that stops me getting full fat atmos from my oppo203.

Where I am coming from is that if you want a Sonos HT speaker to play DD5.1 you have to send it DD5.1.  Although id you want Atmos on the Arc it needs to be DD+

I’m not worried about DD 5.1 I just would like it to output correctly so multichannel pcm 5.1 not 7.1.

Yes streaming atmos is atmos DD+ but from my 203 I get Atmos (True HD)

‘ I just would like it to output correctly’

By ‘it’ do you mean the Arc and by ‘output’ do you mean play?

Also, have you considered powering off (not standby) the Apple TV4K and the LG TV for a few minutes and then first power-on the TV and set it’s HDMI-2 eARC port to ‘pass-through’ and then power on the Apple TV4K to see if that fixes the issue.

Yes sorry, I want the ARC to play multichannel pcm 5.1, for me its “outputting multichannel pcm 7.1. 

Well I did power it all off the other week, but I will give it a go, although I dont seem to be the only one with this issue, so Im not hopeful it will solve the issue, but thank you for the suggestion.

ledzep1,
I see this in the ‘About my Sonos System’ for the Arc when playing an ATV Netflix DD5.1 source, but it’s an LG C9 TV and an Apple 4HD (not 4K) (just set to ‘Auto’ audio out). So not sure if that is what you’re looking to see as your output/input? I’d expect the ATV 4K to output the same audio, but note I am running the latest ‘public beta’ of Apple’s tvOS software.

I think it is playing what you are sending it, so the solution is to send it PCM5.1.