Trending Lyricist I

Multichannel PCM 5.1 dropping out since 14.10 update

516 replies
36731 views

Anyone else experiencing the same issue? Multichannel PCM 5.1 blanks out for a second every 1-2 minutes. I don’t think it’s a bandwidth issue as it works flawlessly with Multichannel PCM 7.1 (thorough test) and Dolby TrueHD Atmos (quick test). And it may have been caused by the Sonos 14.10 update. Setup is PS5→ LG C1→ Beam 2 (via earc).

2 weeks ago before the 14.10 update, I watched a bluray film wherein I had my PS5 transcode the DTS-HD MA 5.1 audio to Multichannel PCM 5.1 (as the C1 does not support DTS) and had no issues. Earlier today, I played a bluray film for the first time in 2 weeks and I encountered consistent audio dropouts every 1-2 minutes. It had the same setup where DTS-HD MA 5.1 → Multichannel PCM 5.1. I tested other bluray discs including the one I watched 2 weeks ago and they all now have the same issue.

Curiously, I’ve been gaming heavily on my PS5 the past two 2 weeks and haven’t had any audio issues. Then I realized that I’ve been using Multichannel PCM 7.1 when gaming on my PS5. So I made some changes under the PS5 sound settings to make it output Multichannel PCM 5.1 instead. Lo and behold, I am now getting the same consistent dropouts in games and even on the PS5 main menu.

I think it’s due to the Sonos 14.10 update as that’s the only firmware update I’ve done in the last 2 weeks. No PS5 update, no LG C1 update. Well actually while I was composing this post, I received and applied the latest LG C1 firmware update and I still have the same issue.

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.

Pinned Reply By Corry P

Hi @throwawaybeam2 et al

We now recommend you reach out to the TV manufacturer (LG) as this behaviour is also occurring with different soundbar manufacturers (so it’s not a Sonos-specific issue).

Alternatively, please utilize different audio formats from McLPCM 5.1 (e.g., McLPCM 7.1, DD+, etc).

I hope this helps.

View in thread

Show previous replies

J

jay house

Avid Contributor III

Ah, I see. I didn’t realise multichannel LPCM required eARC.

I’m a little confused as to how the fault could be with the TV though if it’s set to just passthrough the bitstream?

R

RANDUSR23296

Enthusiast I

Ah, I see. I didn’t realise multichannel LPCM required eARC.

That hadn’t occurred to me either until I tried it, or that the Amp was just ARC.

I’m a little confused as to how the fault could be with the TV though if it’s set to just passthrough the bitstream?

Presumably the TV shreds the HDMI data stream from the console/bluray and only copies the audio stream to the eARC HDMI port. There’s enough software there for a memory leak or an exception to disrupt the process inside the TV, we know the Beam 2 is reporting the stream drying up. From reading other threads and forums it seems LG have had a difficult time stabilising multichannel LPCM, especially on the 9/X models. Having said that, it doesn’t rule out the Beam provoking the TV into quitting sending data. Would be interesting to know if the diagnostics had shown any kind of handshake during the recovery of the audio drop outs.

R

RANDUSR23296

Enthusiast I

My 5.1 dropouts seem to have gone, none for at least 12 hours of music/films/games. Sadly I cannot attribute a single setting to the behaviour change. I decided to test removing the (wireless) surrounds which did not fix the dropouts, so I added them back to the Beam 2. Then

Toggled “Sound Mode Share” out of curiosity (as it was mentioned in another thread) - didn’t notice any obvious change
Changed “passthrough” to “auto” - this changed the Beam input type from “Multichannel PCM 5.1” to “Dolby Multichannel PCM 5.1” (whatever that’s meant to be - I’m guessing MAT?). This format however had no dropouts for 10 minutes or so, so I flipped back to “passthrough”, but I don’t remember if the dropouts returned at this point :(

my colleague spotted some issues happening on the CEC network and suggests you factory reset your TV

Before factory resetting the TV as my next step (it’s not my main TV so not very inconvenient) I thought I’d try manually switching the devices on from standby instead of using CEC.

Then I noticed the dropouts had gone on “Multichannel PCM 5.1”. I then toggled CEC control on the source devices and the drop outs haven’t come back even when using CEC to standby/powerup .

I’ll try to isolate the steps above if the dropouts return, but I can see why the problem is not wide spread, seems to be a temporary state involving the C1/Beam2, possibly cleared by either the auto/passthrough setting or CEC order.

B

Blanks27

Lyricist I

I can confirm that I am having the same issues on my LG C1 Oled with beam gen 2. The only audio file that I have cut outs with is PCM multichannel 5.1, when playing blu rays on my Sony X700 blu ray player. All other formats work fine, including Atmos. Neither Sonos support or LG support have been able to help. Really frustrating as obviously a lot of blu rays have 5.1 tracks on them and I would rather not have to watch them with standard stereo pcm which sounds as bad as the TV speakers. (Hyperbole).

R

RANDUSR23296

Enthusiast I

PCM Multichannel began cutting out again, now on Sonos v14.16 still LG v03.33.11. I tried toggling all the settings I tried previously (I didn’t see “Dolby Multichannel PCM 5.1” this time, only stereo) and disabling CEC on the sources but the drop outs persisted.

I then factory reset the C1, but that did not clear the issue either, so I then generated diagnostic #997513791.

Ken_Griffiths

PCM Multichannel began cutting out again, now on Sonos v14.16 still LG v03.33.11. I tried toggling all the settings I tried previously (I didn’t see “Dolby Multichannel PCM 5.1” this time, only stereo) and disabling CEC on the sources but the drop outs persisted.

I then factory reset the C1, but that did not clear the issue either, so I then generated diagnostic #997513791.

If you have tried the various things mentioned in this thread and it’s repeatable, then it is suggested earlier by Staff, to get in touch with the Sonos technical support team directly, so they can perhaps look into the matter. I would perhaps give them a call and see if that leads to the issue being resolved with your TV/Devices.

R

RANDUSR23296

Enthusiast I

Support have raised a case. I also decided to time the audio drops, I thought they were random but today I measured them as a regular 39.8 seconds apart.

R

RANDUSR23296

Enthusiast I

The dropout duration is almost exactly 1 second, which leaves 38.8 seconds of sound (crudely measured by recording onto my computer). If my assumptions (LPCM signal is 24-bit/channel, a full channel is wasted on LFE) and calculations are correct then probably still co-incidence that this is close to the region of 32MB of data:

2^25 Bytes / 6 channels / 3 bytes / 48KHz = 38.836 seconds

R

Romancin

Lyricist II

Same problem here since Sonos v14 update with LG C1. Really frustrating :(

In my case, I have 1 second cutoff every exactly 59 seconds.

K

kikeminchas

Lyricist III

Earlier in this post I mentioned unplugging and restarting all devices fixed it but it comes back after a while. It seems some actions, either changing settings, unplugging cables, resetting devices fix it for a while but it comes back, even if no changes in setup are done. This is not such a weird scenario either... My PS5 can output Dolby 5.1 instead (no dropouts) but prefering uncompressed audio from the source is completely normal if your device supports it?

@RANDUSR23296 , could you keep us updated here if you receive a reply to your support case? Many thanks.

Show more replies

Sign up

Login to the community