Since this is happening only on your device, and apparently nobody else’s, I’d lean towards LG….but only after a reboot of your system, including the TV and Sonos Arc, to make sure that all the various operating systems are “refreshed”. Entirely possible it’s just a bad load of an OS/software on one of the devices. Never hurts to do the famous control-alt-delete :)

There is one other post of someone having same issue. Also an LG…. Hmm…

Hmmm, haven’t seen that particular post yet, although I probably will. Again, an LG, so the chance is much greater it’s on their side of things, otherwise folks like myself with Vizios, or other TVs would be complaining, too. 

Still the possibility of a local issue, with just two folks reporting it. I’d think it it was endemic with all LG versions of the eARC code, there would be dozens or more posts. I’d still recommend the various reboots. 

I have changed the HDMI, re ran the earc setup, re booted TV, and sonos and I still get blasting arc when TV turns on. If you turn it off the TV  real fast and turn it back on it is normal sound.  I do notice the arc has a green led when this happens. Sonos please help.

LG nano9175 TV

Hi @Mcp8189, thanks for reaching out! I suspect that the increase in volume is coming from the TV, however I’d recommend recreating the issue and then submitting a diagnostic. 

Once that’s done if you reach out to our Customer Care team via either live chat or phone call and let them know the confirmation number, they’ll be able to take a look at the diagnostic and confirm what’s going on here.

Let us know how you get on!

I also have a LG Nano, and experience this a few times per week.  The fix has been the same, to quickly turn off the ATV/TV and reboot, and it works fine.  Seems as though there is no connection to the Arc in the initial startup, and the TV speakers are incredibly loud.  Unfortunately, the sound is so loud trying to grab a diagnostic report isn’t really an option, and I do not know that there would be a useful report since the light on the soundbar is green and doesn’t look like it is connected to the TV.  

Since the Arc isn’t connecting to the Nano, I have assumed it is an LG issue with the TV not seeing the speaker as it turns on.

@khaz22

I would certainly try powering off (not standby) everything for a minute or two for starters and check the HDMI cables are seated correctly at both ends.

In addition to having ‘Simplink’ enabled, have you perhaps also switched on ‘auto-power-sync’ in the LG TV Settings to see if that makes a difference - perhaps also worth a try is switching off ‘HDMI-Ultra HD Deep Colour’ and ‘Instant Game Response’ on the HDMI-2 port to maybe see if that may help resolve the matter too.