Beam: PCM vs Dolby

  • 8 December 2018
  • 13 replies
  • 9558 views

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As we mostly all know by now, some TV’s (especially LG) have lip sync issues with the Beam.

Most people report that switching from Dolby to PCM helps the problem. So before I buy a Beam, can anyone tell me what the real world
difference is in sound quality and UX (when not using the Beam with any other speakers). Is it really noticeable? If I’m really going to be missing out, should I look at other options?

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13 replies

@melvimbe
I’m not sure what you mean by connecting the DD source (audio only) bypassing the tv. The beam only has one input (HDMI). How can I achieve this without introducing some other hardware?


The Beam comes with an adapter to convert optical to HDMI-ARC (in a way). So you can connect an optical output (your TV or Sky box) to your Beam.


PCM setting on TV (I.e. disabling DD) still has a delay. Not as bad but nonetheless a delay. The audio comes out after lips have moved so no amount of adjusting delay on sKY mini box (sat) or the TV audio sync has no effect. It would require a minus adjustment.


Right. That's why I was suggesting connecting the optical audio output from the Skybox directly to the Beam. If the lip sync issue is resolved, then at least you know that the delay is introduced in the TV (which it has been in most cases I've seen).


This is a 2 month old tv. I expected too much from Sonos to have a enhanced experience. I just refrain from watching HD channels for now


Why are you assuming that Sonos is causing the delay? If Sonos doesn't receive the audio on time, there is no way they can play it on time. And 2 months old...is that when you bought or when the product was first released. I did a quick look at your TV and couldn't see a release date. But based on the fact that it doesn't appear to be 4K, I'm guessing the model is a few years old.

Regardless of the age though, there are current TV models that have an issue with delaying audio.
@melvimbe
I’m not sure what you mean by connecting the DD source (audio only) bypassing the tv. The beam only has one input (HDMI). How can I achieve this without introducing some other hardware?

PCM setting on TV (I.e. disabling DD) still has a delay. Not as bad but nonetheless a delay. The audio comes out after lips have moved so no amount of adjusting delay on sKY mini box (sat) or the TV audio sync has no effect. It would require a minus adjustment.

This is a 2 month old tv. I expected too much from Sonos to have a enhanced experience. I just refrain from watching HD channels for now
For my issue, I will look at connecting the tv to the Sky box with optical connection and go from there.


????. TVs don't accept optical inputs. Not sure what you meant here. And maybe I don't understand what 'Sky box' is. I'm assuming it's your cable/satellite box?


Why would I want to spend £££ on a 5.1 soundbar only to use PCM?


If you had no interest in surround sound for whatever reason. I know plenty of folks who have a soundbar capable of 5.1 who are only interested in better audio than their tv.


and as for buying a new TV :D:D:D:D You're funny.


It makes sense depending on the age, quality, and features of your TV. Or perhaps, if you've got a different older TV in the house you want to upgrade. I agree, don't get a new TV just so it will work better with Sonos or some other sound system, get it for other reasons as well, if those other reason matter to you.
For my issue, I will look at connecting the tv to the Sky box with optical connection and go from there.

Why would I want to spend £££ on a 5.1 soundbar only to use PCM?

and as for buying a new TV :D:D:D:D You're funny.
If there is no delay with PCM, but there is with DD, then it seems logical that the TV is processing the DD signal and causing a delay. I would look at the audio settings on the TV to see if there is any sort of processing I can turn off. If nothing is there to change, my next step would be to verify that my sources are sending audio in DD, so my TV isn't having to do any conversions.

Last step would be to try connecting a source that's sending in audio in DD directly to the TV, bypassing the TV altogether. Hopefully this can be done by optical, so HDMI still goes to the TV. If there's no delay, then it's clearly the TV causing the delay.

If the TV can't sending anything beyond PCM without causing a delay, then you're going to have trouble passing anything through the TV. You'll need a solution that doesn't pass through the TV, or get a new TV.
Well my LG oled works great with my sony AVR via optical, so this is beginning to sound like a sonos beam only problem.
Can you not induce an audio delay in sonos or tv or sky mini box?
I've tried with both the TV settings and SKY Mini box but quickly worked out that it needs to be a negative delay rather than introduce more delay (if that makes sense), which is how the increments go. 😞
Userlevel 7
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Well my LG oled works great with my sony AVR via optical, so this is beginning to sound like a sonos beam only problem.
Can you not induce an audio delay in sonos or tv or sky mini box?
What TV do you have? What source? I thought this was primarily an LG issue...

No, it's never been solely a LG issue, where did you get that from?

Samsung M5500 (5 series). Source is SKY Minibox on HD (surround) channels only. Exhausted all avenues with Sonos support aside from calling them directly.
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Using the supplied optical adaptor in the box makes no difference, I still experience lip sync issues. As well as audio drop outs and incompatibility with Samsung. The list goes on...

What TV do you have? What source? I thought this was primarily an LG issue...
Using the supplied optical adaptor in the box makes no difference, I still experience lip sync issues. As well as audio drop outs and incompatibility with Samsung. The list goes on...
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Shame we can’t use optional for the audio, and ARC for control - or can we?
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Is that that all I would lose? I hear the TV control functionality is a bit janky anyway, so that might be a good option, thanks.
Userlevel 7
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You could always use the beam via optical lead, surely there is no lip sycn issues with optical?
That would give you all the sounds quality of DD5.1, just loose the whistles and bells of controlling your tv, just use tv remote 😉