Due to having an older receiver that does not have HDMI inputs, I was planning on using the TV to switch between my HDMI devices (TiVo & PC) and have the TV output the audio to my receiver over the optical connection. What I found was that the TV would not pass Dolby Digital sound from the HDMI inputs to the optical output, only PCM audio. The TV does output DD from the built in tuner over optical, but not from the HDMI inputs.
The solution I found is changing a setting on the LG OLED TV in the service menu (EZ Adjust), you need to change the EDID setting under Tool Option7 from PCM to AC3. After doing this and powercycling the TV it now tells HDMI connected devices that it supports Dolby Digital. I also noticed that the EDID setting had the following options (PCM, AC3, DTS, DTS-HD) so it may be able to support pass through of other audio formats, but I only needed AC3 Dolby Digital so that is all I tested.
There are different ways to access the service menu (EZ-Adjust) on the LG TV, I used a Logitech Harmony 650 since I had one (other Harmony models should work to).
This assumes you have a Harmony remote, a MyHarmony account and the MyHarmony software on your PC.
1. Start MyHarmony software and log in to your account
2. Click on "DEVICES" tab and click on "Add a device"
3. In manufacturer field enter "LG" and in model number add 47LE5300-UC and then click on Add. Your device should now be added.
4. Click on "Buttons" and then under “Remote Buttons” select LG 47LE5300-UC in the select box and click on "Go"
5. On the right hand side of the screen you should see all the commands for this device, just drag the EZ-ADJ command to an unused button on the remote.
6. Once you are done click on "Save"
7. Remember to sync your remote
Process used on the LG OLED TV 55EG9100.
1. Turn on the TV with the LG Smart Remote
2. Select the LG 47LE5300 device on the Harmony 650
3. Press and hold (about two seconds) the key on the Harmony 650 that you programmed for the EZ-ADJ command until a password box shows up on the TV (note: this is the only step where you use the Harmony 650 remote, use the LG Smart Remote for all other steps
4. Using the LG Smart Remote enter the password 0413
5. Arrow down (don’t use the pointer) to “6. Tool Option7” and hit enter
6. Select the “EDID” option and change PCM to AC3
7. Hit the Exit button on the remote
8. Powercycle the TV & HDMI connected devices
Settings on the LG OLED TV after enabling AC3 Dolby Digital.
1. Select the HDMI input device that you want to enable Dolby Digital pass-through (you need to do this for each HDMI input where you want DD enabled).
2. Press the Setting button on the remote and go to Advanced Settings
3. Select Sound
4. Set Sound Output to “Audio Out (Optical/HDMI)”
5. Set Digital Sound Out to “Auto”
6. Under Sound Out go to the “AV Sync Adjustment” and adjust sync to -5. (note: I noticed that after enabling AC3 on the HDMI inputs there was a Video/Audio Sync issue that you need to adjust out on each HDMI input, I used some AV sync videos on YouTube.)
So far this seems to work
, I get Dolby Digital from the TiVo when the program outputs DD and get PCM if the program ouputs PCM to my receiver. I will update if I run into any other issues.