Quiet, muddy sound DD5.1 through Beam

No idea what CH9HD is....but I'll assume it's a standard Dolby Digital signal.

To be honest, with what you're describing, I'd be taking a look at the audio settings on the TV set. It sounds to me like the TV may be messing with the signal before it gets to the output. Take a look at the TV's audio settings, and turn off anything that might be modifying the signal. Things like MPX and Auto Gain Control. Make sure that Digital Audio Preference is set to DD. SPDIF is set to Dolby Audio.

This is all on pages 87 to 97 of the manual for the TV. I may have missed a setting or two, but basically you want the TV locked down to Dolby Digital, and not modifying the signal its getting in any way before it outputs to the HDMI/ARC.

Hi Bruce,

Firstly, thank you for the help! Very generous with your time. CH9 HD is the HD broadcast for Channel 9, one of our free-to-air channels. I have been A/B testing with the SD Channel 9 as it comes through in stereo.

I have had the Digital Audio preference set to DD and the SPDIF set to Dolby Audio. All other settings are actually greyed out.

I’m trying to follow an elimination process, but just struggling to figure out how. The elements in the chain are:

- Source Content / Broadcast
- Media Player (Pana FZ series TV)
- ARC output
- HDMI cable
- Sonos Beam

I have an old Apple TV 3, so could probably flick between Netflix on it and TV, but I have 4K available through tv so not sure if that’s a good A/B test

No worries, happy to help wander through this (in my mind).

I don't think we care whether or not its 4K or not, we're not dealing with the video, just the audio aspect. A/B testing with a stereo channel is a smart thing, it helps narrow down where the issue is. If you're getting sound out of the Beam in stereo, then we know there's not an issue with the Beam, and it's down to figuring out what's going on with the Dolby Digital signal.

And, at this moment....I'm at a loss. If it works fine with the stereo signal, that means that the CEC handshake with the Sonos device has worked, and it's propogating the signal out of the ARC/CEC connection down to the Beam. So we know that that's working.

I should have bookmarked the manual when I was looking at it online. But at least it's good that all the other options are greyed out now.

If I remember correctly, there was an option to switch it to Bitstream (PCM). Give that a shot, and see what happens. Specifically, I'm looking (or you are) a piece of data in the settings of the Sonos app. If you click on "more..." and then settings, you should see near the bottom of the list an option for "about my Sonos System", or words to that effect. If you click on that, it will give you a list of all of your Sonos components that it sees connected, and various bits of information. The one I'm most interested in is under the Beam settings, and should be something like Audio Line In, or something like that. If you're getting sound out of the Beam, it will say either Stereo or Dolby Digital.

I'm really at a loss here. If you're getting stereo, then everything should also be working with Dolby Digital, on the HD channel. I didn't look at the specs page of the manual, but it's hard for me to believe that an HDMI/ARC would ever be stereo only. Just doesn't make any sense.

To be honest, the other thing I'd try is using the optical output on that TV, and using the adapter provided by Sonos to connect the optical cable to the Beam and see if that works better. Can't figure out why it would, but it is worth a shot.

I'd still recommend that you submit a system diagnostic and post the number here, on the offhand and extremely rare (unheard of, honestly) possibility that there's some sort of hardware fault in the Beam that is causing Dolby Digital not to be processed, but stereo working. And then I'd be bugging Panasonic.

At the end of the day, you may be better off contacting Sonos directly. They probably can do a better job of remote diagnosis than I can.

I think will do both: system diagnostic and contact Sonos.

I should clarify as well - DD5.1 is playing through, it just sounds very weak compared to stereo. The Sonos app reports Dolby Digital 5.1. It just sounds like a small, muddy speaker with no soundstage at all. Vocals coming through are very disconnected from faces on screen.

I'm pretty suspicious of the TV, despite it being a decent one. However, there are a couple of threads on this forum that describe this issue with v9+ software, but not on v8x software. Eg,

https://en.community.sonos.com/home-theater-228993/sonos-beam-dd5-1-problem-6810138

That's the only thing that has me wondering if there's an issue with the beam processing 5.1 - I simply can't think of how to eliminate down. I think I'll have to grab that optical lead and see if that makes a difference

Last thing to note is that some of the menu items listed in the manual for the TV aren't actually in any of the menus. Fairly certain it's set OK.

Diagnostic Ref #: 63082766

I have noticed something quite odd.

- if I start an episode on Netflix with Stereo, then switch to 5.1, I get big sound, but poor vocal focus
- when the next episode starts, small sound with large vocal focus.

I’m starting to think it’s TV....

Well, I’m at a loss, can’t figure out how a TV could be doing that to the DD signal...unless it’s broken in some way. If you’d be so kind, please come back and let me know what you find out, I’m fascinated at this point.

No problem Bruce, will do. Might take some time to get to the bottom of this, as I have a baby and a toddler and finding time to access live help isn't easy!

I have a plot twist: Live switching between audio out formats produces odd behaviour. Here's the latest test

## Set Up
- Embedded Netflix app
- Atypical TV Series 1
- 4k HDR format (according to the Netflix info)

1) Start an episode with Dolby Digital output on TV
- Sound is small, muddy, not great

2) Switch to PCM output on TV during the same episode
- Sound improves
- I left the TV on PCM out for the remainder of the episode

3) Start the next episode with PCM output on TV
- Sound is still great, but louder, bugger!

4) Switch to Dolby Digital output on TV during the same episode
- Big sound! Huge soundstage - perhaps too big. As in, voices seam too wide, almost like they are coming from behind the screen. Almost like a simulated surround mode (remember Pro Logic? lol)
- I left the TV on Dolby Digital out for the remainder of the episode

5) Start the next episode with Dolby Digtial output on TV
- Sound is small, muddy, not great. Back to the start....
- This is quite telling, as the audio quality changes dramatically from the previous episode (where audio out was changed mid-viewing) to this episode, without actually touching any settings.

## Theory so far
- Probably something to do with the TV or the ARC connection
- I have no knowledge whatsoever of 'CEC handshakes', so don't know if this could be a contributing factor
- This is a bummer, as there's no Panasonic community that's as engaged as this Sonos one that I know of. I feel if it's a TV issue, I'll have a much harder time of getting help

Will continue to add updates here though 🙂

Update: tried the optical to hdmi adapter that came with the beam. Toslink connector in the TV, HDMI connector in the beam. No change (other than losing volume control from TV remote)

To me, this simply rules out a potential HDMI ARC issue with the TV. We still may have an issue with the Sonos Beam, and with the TV interpretation of DD5.1

Have you talked to Sonos regarding the diagnostic you submitted?