Answered

Dolby Multichannel PCM

  • 17 December 2022
  • 9 replies
  • 8832 views
T

Hi,

 

I recently bought a Sonos Arc. And I’m wondering if the settings are correct. 

 

I have a Samsung Frame (2022) with a one-connect box which has HDMI e-arc, which I connected the Arc to. Now watching most streaming services I end up getting Dolby multichannel PCM 5.1. Unless the show is offered in Atmos, then Atmos will show up in the app. 

 

So my question is why I don’t get Dolby Digital plus instead. 

 

I’ve checked my TV settings and I can’t choose ‘passthrough’ watching built-in apps like Netflix. 

 

My setup is:

Arc

Sub (gen 3)

2 SL Ones

 

Curious to hear what you think.

 

Thijs

icon

Best answer by Corry P 20 December 2022, 13:37

View original
This topic has been closed for further comments. You can use the search bar to find a similar topic, or create a new one by clicking Create Topic at the top of the page.

9 replies

Corry P
Userlevel 7
Badge +18

Hi @Thyz 

Welcome to the Sonos Community!

I can’t really say why you get PCM 5.1 instead of Dolby Digital, but it will have something to do with the TV’s settings.

What I can tell you is that if the Arc did receive Dolby Digital, it would then decompress the stream into PCM prior to playback (because it has to - all formats/codecs need to be decompressed to PCM because that’s how digital audio devices handle audio internally), so the only thing that would change is which device is doing the decoding, and I very much doubt it will make much difference.

If you get 5.1 playback when you should, and Atmos playback when you should, then everything is as it should be.

I hope this helps.

"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein
G
Userlevel 7

Set the HDMI-eARC Mode setting on your TV to OFF you should get Dolby Digital Plus audio from the native apps. 

"Receive with simplicity everything that happens to you." - Rashi
P
Userlevel 6
Badge +5

In my humble opinion, PCM is superior to DD+. So I  think your TV is making a good choice sending PCM when it can and you should be happy with it. 

Corry P
Userlevel 7
Badge +18

Hi @ProfessorFrag 

In my humble opinion, PCM is superior to DD+. So I  think your TV is making a good choice sending PCM when it can and you should be happy with it. 

This is very true, but if the source media isn’t a Blu-Ray (which it isn’t - TV apps are mentioned) then it’s very likely that the received PCM has been decompressed from DD+ by the TV, and is therefore the same (the TV and Arc possibly even use the same software libraries to decode DD+, which would result in identical output).

From physical media, PCM is indeed likely to be higher quality, it being a lossless format.

I agree that the OP should be satisfied, however - they’re getting what they should be getting, either way.

"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein
T

Thank you for your replies!

 

I’m not as knowledgeable on the subject as you all are so when you tell me that PCM or DD+ doesn’t really matter for sound quality, I’m happy!

 

Cheers,

Thijs

P
Userlevel 6
Badge +5

Hi @ProfessorFrag 

In my humble opinion, PCM is superior to DD+. So I  think your TV is making a good choice sending PCM when it can and you should be happy with it. 

This is very true, but if the source media isn’t a Blu-Ray (which it isn’t - TV apps are mentioned) then it’s very likely that the received PCM has been decompressed from DD+ by the TV, and is therefore the same (the TV and Arc possibly even use the same software libraries to decode DD+, which would result in identical output).

From physical media, PCM is indeed likely to be higher quality, it being a lossless format.

I agree that the OP should be satisfied, however - they’re getting what they should be getting, either way.

Totally agree on the quality of the soundtrack itself. But since PCM is uncompressed, TVs can mix their sound effects into the movie soundtrack. The boops and bongs for the menu etc. While in DD+, TVs often have to turn off the movie sound if they want to play an operating system sound. Unless they are fancy enough to decompress, mix in the sound, recompress; and still get it out without lag.

Same reason Xbox and Apple TV use LPCM. It’s just a little nicer.

Corry P
Userlevel 7
Badge +18

Hi @ProfessorFrag 

Totally agree on the quality of the soundtrack itself. But since PCM is uncompressed, TVs can mix their sound effects into the movie soundtrack. The boops and bongs for the menu etc. While in DD+, TVs often have to turn off the movie sound if they want to play an operating system sound. Unless they are fancy enough to decompress, mix in the sound, recompress; and still get it out without lag.

Good point - I hadn’t considered that!

"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein
S

Set the HDMI-eARC Mode setting on your TV to OFF you should get Dolby Digital Plus audio from the native apps. 

can you advise why earc should be off for dolby digital plus?

 

G
Userlevel 7

Set the HDMI-eARC Mode setting on your TV to OFF you should get Dolby Digital Plus audio from the native apps. 

can you advise why earc should be off for dolby digital plus?

 

Because it seems like with eARC set to Auto, the TV is converting the native Dolby Digital Plus audio from streaming apps to Dolby Multichannel PCM.

Also, eARC isn’t necessary to get the highest quality audio (Dolby Digital Plus/Dolby Atmos) from the native streaming apps.

"Receive with simplicity everything that happens to you." - Rashi
Terms & ConditionsCookie settings