Maybe try switching off HDMI-CEC control on any ‘other’ devices that are connected to the LG TV HDMI ports 1, 3 and 4.

Also, If the TV allows, set the ‘Digital Sound Out’ on the HDMI-ARC to ‘pass-through’ and see if those things fix the issue for you.

Note after switching off CEC on your other devices, it is also worthwhile rebooting the connected device too.

Hi Ken,

Thanks for your note, unfortunately on the LG TV I have, turning off SIMPLink will also disable ARC, so without resorting to optical, I need it on.

The only device I have connected is a Firestick and I have disabled CEC on that, so I’ll see how I go.

Thanks for you help.

That’s not what I was suggesting @Robert100 - it’s a case of leaving Simplink ‘ON’ on the LG TV, but switching off CEC on your ‘other’ HDMI connected devices. So if you have Apple TV for example then switch off CEC in its settings and reboot it… do the same for devices connected to HDMI ports 1, 3 and 4.

If it resolves your dropout issue, then switch CEC back ‘ON’ on each device, just one at a time, and test for a while to see if the issue returns and if it does, then leave CEC ‘OFF’ on that one device only.

Thanks Ken, as per post, the only connected device is a Firestick with CEC disabled. SIMPLink still on for above reason.

Ah sorry I missed the fact you had switched off CEC on your FireStick - I have an LG C9 TV and that has  the older FireStick 4K attached and has been fine with CEC enabled with the eARC port on the TV enabled and set to ‘passthrough’ - maybe try the FireStick on a different HDMI port as that can sometimes make a difference in some cases.

If I still get it, I may just revert to the TV built in Netflix etc. useful to hear that this works with the 4K (which I have) and SIMPLink.

Hi @Robert100 

Welcome to the Sonos Community!

Have you tried unplugging your TV from power for a couple of minutes? If not, I recommend it - it resolves the majority of such cases.

I hope this helps.

Thanks Corry, 

This has been an issue for 2 years, so yes power has been switched off multiple times over that period (including disconnecting to change rooms).

Thanks,

Robert.

Hi @Robert100 

Is there any change if you disconnect the Firestick from the TV?

Hi Corry, that is the only thing I have not tried, as I don’t ever watch live TV and don’t have any other sources to test with.

Thanks,

Robert.

Hi @Robert100 

The part about not watching live TV I get - I don’t either. I find watching adverts weird now.

Do you have a laptop? - it might be a source that you have not considered to be a source.

Looking at the diagnostic, the issue is readily apparent, but all I can tell you about it is that it is regarding the feed from the TV - “Could not get input delay (RESTART)”. When the feed arrives at the Beam, enmeshed within it are instructions on how long to delay it by (usually 0). For some reason, your Beam is unable to determine a value. Whether this is due to the TV or the Firestick I am unable to determine. Tolerating adverts for an evening way be the only way to determine the source of the interruptions.

I highly recommend checking both the TV and the Firestick for any available software updates. Reseating the HDMI cable by swapping the ends around might fix the issue, but considering the error I see (which I don’t remember seeing ever before) I think it much more likely that a device is operating outside of specifications (and considering the number of Firesticks out there, it’s probably the TV).

I hope this helps.

Hi Corry, actually, thats super helpful, as I have experienced very odd sync issues with the the FireTV, so that correlates. I have performed a factory reset, and updates on the stick, so I might just order another one and see if a more recent model performs better.

I do have many other sources of course in different rooms, I just don’t watch any of them for hours at a time, for the intermittent fault to appear.  

While I think of it, I may see if I can update the TV, as the ARC firmware may be involved. 

Thanks again.

Hi @Robert100 

Did you fix the issue? Because I have the same problem.

several factors can contribute to the problem. Here are some potential causes and solutions:

HDMI-CEC (Consumer Electronics Control) is a feature that allows devices connected via HDMI to communicate and control each other. In some cases, HDMI-CEC conflicts can cause audio switching issues. Try disabling HDMI-CEC on both the LG TV and the Sonos Beam.

Ensure the LG TV's audio output is set to "External Speaker (Optical/HDMI ARC)" and not "TV Speaker." Check the TV's audio settings menu to confirm this.

While a standard HDMI cable should suffice for audio transmission, using a high-quality HDMI cable specifically designed for ARC can sometimes resolve audio switching issues.

Ensure both the LG TV and Sonos Beam have the latest firmware updates installed. Outdated firmware can lead to compatibility issues.

If none of the above steps resolve the issue, consider performing a factory reset on both the LG TV and the Sonos Beam. This should eliminate any software glitches or configuration issues.

Moderator edit: This response is likely AI-generated.