LG WebOS v3.11.25. No Volume Control with ARC

Hello I have a LG 65 CX OLED running WebOS v3.11.25. I have pretty much everything working except for volume control via ARC.

Things I have tried:

  1. Enabled IP Control via the Hidden Menu
  2. Set Single Device Control on the Roomie Primary Controller (this sped everything up)

Additional Info

  1. I can toggle mute from Roomie but not turn up or down the volume when ARC is selected for Sound Output
  2. If I select TV Speakers it works fine.
  3. The physical TV Remote will adjust the volume in either mode, although the visual prompt is different depending on if I use the internal speakers or ARC.

Im wondering when the TV is in ARC mode if it needs a different command sent to it vs the Standard Volume Up/ Down?

I am open to alternative configs, I just want to be able to control the volume of sound bar with an IR Blaster. Maybe optical would work better?

Then you would setup control of the sound bar. You wouldn’t try to relay it through a TV.

I mistyped my original post. I didnt / dont want to use a blaster.

For what it’s worth. Here is how you can control the sound-bar via the TV.(Plus additional steps to get full functionality out of roomie)

  • Connect both Optical and HDMI between the TV and the Soundbar.

TV Config:

  • Sound Output = Optical /w Volume Sync over Optical
  • HDMI - CEC Enabled /w PowerSync (This allows the TV to power on / off the soundbar)
  • IP Control - TV’s Settings Menu > Keep the Network icon focused, then enter numerical key 828888 using TV’s IR Remote.

Roomie Config for TV

  • Discover TV as usual
  • Disable Relay (This really helps with performance)
  • Add the TV to an Activity
  • In the Setup for the Activity, locate the TV startup commands and add:
    • Set TV as Volume for the Activity
    • +Wake on Lan and enter the MAC address of the active network interface for the TV (This will let roomie turn on the TV)

What you end up with is using Optical and Volume Sync, and the TV will communicate over the optical cable to the Soundbar to adjust the volume. This allows you to not have to add the soundbar to roomie. This is less about avoiding a device license and more about not having to buy another $100 IR Blaster for 1 device. Soundbars are by far my least favorite device from an IP control standpoint due to most if them not having an IP interface.

To be clear this is a work around. There is something unique about using HDMI-ARC for sound and sound control. For instance when using the built in speakers or optical, what the on screen display shows when you adjust the volume looks different then if you are using HDMI-ARC. And its my theory when using HDMI-ARC you need to send a different command to the tv vs the usual volume+ or volume -. Just a theory though. It is also interesting to note that mute works in any configuration.