LG has released a firmware upgrade for the B9/C9/E9 supporting multichannel PCM passthrough. This is great except Arc doesn’t support it yet.
Because of this new update, my Apple TV decides it should use LPCM instead of Dolby Digital 5.1 with Atmos enabled resulting in only 2.0 audio for non Atmos content. The current only workaround is to disable Atmos and enable it when you want to watch an Atmos file. Very frustrating as the previous firmware had no issue.
Ledzep1,
Apple TV 4K is able to output DD 5.1
In Audio Format, click on Change Format, and the new format will become DD 5.1. The issue with this will be you will not receive full Atmos, and will need to change it back if you are watching a show or movie which you need it to be enabled.
Hi
Thanks, but I was aware of this and getting dolby digital 5.1 and atmos before the LPCM update fine from all content on my apple 4k tv box without having to change any settings.
With this update I still get atmos, but all dolby is not down mixing correctly to multichannel PCM 5.1 instead it's outputting 7.1.
That may be a temporary solution I agree.
Thanks for the reply khaz22 and ledzep1. I have been doing this ever since I bought the Sonos Arc but I was under the impression that this latest update would fix this and I wouldn’t need to keeping switching Is that not the case?
Well for me I have never needed to change settings, I have always got atmos and dolby 5.1 perfectly fine on the auto settings via apple tv 4k.
But since the LPCM update, it works as intended in outputting LPCM for dolby 5.1 content but it is outputting as multichannel PCM 7.1, it should be 5.1.
If you go into the apple 4k tv settings you will see that on auto settings the apple TV states it sends audio as uncompressed LPCM which I believe is better quality to dolby 5.1.
Its just not doing it correctly and outputting as 7.1, not sure where the issue lies.
I think I should create a separate thread for this as Sonos might not be aware of an issue.
So do you have EARC or just ARC? also what TV do you have? I’m thinking it might be a problem with my Panasonic GZ950.
Ledzep1,
Apple TV 4K is able to output DD 5.1
In Audio Format, click on Change Format, and the new format will become DD 5.1. The issue with this will be you will not receive full Atmos, and will need to change it back if you are watching a show or movie which you need it to be enabled.
Hi
Thanks, but I was aware of this and getting dolby digital 5.1 and atmos before the LPCM update fine from all content on my apple 4k tv box without having to change any settings.
With this update I still get atmos, but all dolby is not down mixing correctly to multichannel PCM 5.1 instead it's outputting 7.1.
That may be a temporary solution I agree.
Thanks for the reply khaz22 and ledzep1. I have been doing this ever since I bought the Sonos Arc but I was under the impression that this latest update would fix this and I wouldn’t need to keeping switching Is that not the case?
Well for me I have never needed to change settings, I have always got atmos and dolby 5.1 perfectly fine on the auto settings via apple tv 4k.
But since the LPCM update, it works as intended in outputting LPCM for dolby 5.1 content but it is outputting as multichannel PCM 7.1, it should be 5.1.
If you go into the apple 4k tv settings you will see that on auto settings the apple TV states it sends audio as uncompressed LPCM which I believe is better quality to dolby 5.1.
Its just not doing it correctly and outputting as 7.1, not sure where the issue lies.
I think I should create a separate thread for this as Sonos might not be aware of an issue.
So do you have EARC or just ARC? also what TV do you have? I’m thinking it might be a problem with my Panasonic GZ950.
I have LG cx which has eARC.
Fantastic news 
Any follow up on the issue of Sonos ARC mixing up the channels with LPCM7.1 input?
Hi
We’re currently working on it, but at present have no details as to when that will be released in an update. Currently only 5.1 multichannel LPCM is supported on the Arc.
Hi
We’re currently working on it, but at present have no details as to when that will be released in an update. Currently only 5.1 multichannel LPCM is supported on the Arc.
Thank you for the quick feedback.
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