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spyguy
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Dec 2, 2019

Can't Enable Dolby Digital output when connected to ARC HDMI on Samsung q900

after connecting the the sound bar to the arc HDMI PORT 3 on the Samsung one connect box and enabling cec and disaabling multiple times the only selectable option for digital output on the TV setting is PCM. The other dolby digital options are present but not selectable.  I read numerous other posts and tried many different tests but none worked for me.  I am hearing sound but I presume it is using PCM and not Dolby digital

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Re: Can't Enable Dolby Digital output when connected to ARC HDMI on Samsung q900

Hello spyguy,

 

Thank you for posting and welcome to the community. 

 

It is strange that your TV is not allowing us to select Dolby Digital as an audio format to use over HDMI ARC, as the soundbar does support Dolby Digital. What might be the case, is that the sources we are playing through the TV do not support Dolby Digital, whether this is an app in the TV, your cable box or Blu Ray player, it is possible that they are causing the restriction on audio formats.

 

What I would like to mention for you though, is that PCM, unlike Dolby Digital, is an uncompressed audio format, so you should be getting better quality audio from your system while using PCM as it is affecting the source signal less than Dolby DIgital would. In this instance, as we are getting sound through the system, and PCM should be providing a better audio experience than Dolby DIgital would, I would recommend continuing to use PCM as the audio format.

 

I hope this helps.

 

Keith L - Community Support

Robbon did
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Nov 23, 2019

Re: Can't Enable Dolby Digital output when connected to ARC HDMI on Samsung q900

Hi guys 

 

spyguy my thoughts are that this may be a hdmi handshaking issue between the tv and the bar. Try power off the tv fully leave for a bit then re turn on and adjust your sound settings on the tv to see if it outputs DD.

 

keith - you make an interesting comment in that PCM outputs a better quality sound. My understanding however is that the sound is output from the tv as uncompressed pcm that is then decoded by the soundbar. The soundbar can only out put a 2.1 stereo sound unless you have all surrounds connected for full 5.1. Does the soundbar therefore process the uncompressed pcm to a full 5.1 ? Ie it is capable of decoding a pcm signal to full surround?

secondly for those of us with soundbar plus bass unit (2.1) is the Dolby Digital output through hdmi being further down graded from a lossy DD feed to a 2.1 output ? What is the soundbar actually doing with either an optical or hdmi feed exactly ?

interms of soundbar + bass unit, if this is the case isn’t it better to output from the tv as pcm stereo over optical and live with good quality stereo?

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Re: Can't Enable Dolby Digital output when connected to ARC HDMI on Samsung q900

Hello Robbon did,

 

Thank you for posting and welcome to the community. These are some very good questions and I will do my best to answer them for you.

 

You are correct that the TV will be outputting the uncompressed 5.1 signal via PCM which the soundbar will then decode. It is capable of decoding it into full 5.1 surround audio but will not use the additional channels unless we have the surround speakers connected. Using it in this way allows for a higher quality signal to reach the soundbar before it decodes the information which may be preferable for you.

 

If you are using Dolby Digital as your audio format for a 2.1 setup, the audio quality should not be downgraded at any point during the decoding process.

 

As for what method of outputting the audio to the soundbar from your TV, this will largely come down to personal preference because the soundbar can decode anything from a stereo signal to a 5.1 signal from PCM as it's input and, as stated before, the audio should not be downgraded during the decoding process if you were to use other audio formats.

 

As audio quality is such a subjective discussion, the only way to find what you would be to be the 'best' quality from the soundbar would be to test this yourself and decide which process you prefer.

 

I hope this helps.

 

Keith L

Robbon did
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Nov 23, 2019

Re: Can't Enable Dolby Digital output when connected to ARC HDMI on Samsung q900

Hi thanks 

 

I agree everyone has their own taste.

 

i tested both pcm and DD over optical and hdmi.

 

my preference is DD over hdmi. To me the sound appeared to be more separated and defined. 

each to their own. However it is interesting that in terms of a 2.1 set up there is no real benefit to choosing hdmi over optical other than for cec control.

 

hope spyguy resolved his issue.

spyguy
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Dec 2, 2019

Re: Can't Enable Dolby Digital output when connected to ARC HDMI on Samsung q900

I did some research and learned alot and have figured out what's goin on and it has nothing to do with the sound bar (yay!)

 

The reason I was not getting the Dolby option on the TV was because my roku and my TV are not agreeing on what format to send so the default is PCM.  It's a documented issue.

https://community.roku.com/t5/Playback-Issues-Audio-Video-Power/Dolby-Digital-5-1-surround-sound-aud...

 

I also did more research on PCM.  While I understand that it supports 5.1 audio, it will only do so over HDMI and only if the the TV and source agree to send all of audio channels.  Optical does not have enough bandwidth and will only get 2.1 channels when using PCM.  So it seems that while I'm getting PCM from the Roku, it's still only 2.1 channels.  So my workaround is that my TV now has the same apps as the Roku (Netflix and YTTV).  When using the app on the TV I get Dolby digital to the sound bar and it sounds tremendously better.  I tried changing the Roku audio output settings in every config and I never got it to work...bye bye Roku...

 

This is the link that helped me understand PCM vs Dolby Digital better.  

https://www.lifewire.com/what-is-pcm-1846928

 

Robbon did
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Re: Can't Enable Dolby Digital output when connected to ARC HDMI on Samsung q900

Good stuff.

 

i ditched roku in the  end in favour of ATV.  The ATV has much more choice in terms of customisation for picture and sound.