LG OLED C1/C2 eARC Audio Dropouts: Diagnose the HDMI Chain

Quick Answer

For intermittent eARC sound on an LG C1/C2, prove each audio hop separately. First confirm that TV speakers play the same source without interruption. Then connect only the soundbar or receiver to the LG's HDMI port labeled eARC, use a suitable HDMI cable, and test stereo PCM before Dolby Digital Plus, multichannel PCM or lossless bitstream. Add consoles, streamers and CEC control one device at a time.

This sequence reveals whether the dropout follows the source stream, the TV-to-audio return link, a codec transition, HDMI-CEC state or receiver firmware. Switching every Sound Out and Digital Sound Output option at once may temporarily restore audio but destroys the evidence needed for a stable fix.

Audio-Dropout Symptoms

Describe what the audio system reports when sound disappears:

Sound cuts for one or two seconds and resumes in the same format.

The receiver display changes from Atmos to PCM or Dolby Audio after the interruption.

Audio vanishes after standby until eARC is toggled or devices are restarted.

Internal webOS apps fail, but a console connected directly to the receiver is stable.

Only one app or title drops when it changes between trailers, menus and main playback.

PCM is stable while bitstream Atmos drops.

Both optical and eARC interrupt at the same timestamp.

Video also blacks out. That suggests a wider HDMI or source issue rather than an isolated return-audio failure.

Record source, app, codec shown by the receiver, LG Sound Out mode and the exact event that triggers the problem. “Atmos” can mean Dolby Digital Plus from streaming or Dolby TrueHD from disc; the transport demands differ.

Causes in the eARC Signal Path

Return-channel handshake

eARC uses the HDMI connection between TV and audio device for return audio and capability discovery. Standby, input changes or CEC commands can leave devices with inconsistent state. A cold, ordered restart can clear that state, but recurring failures indicate firmware or interoperability still needs attention.

Cable or port placement

The sound system must use the TV port physically labeled ARC/eARC and the receiver's corresponding output. eARC data uses a dedicated channel, but cable quality and connector seating still matter. An optical cable bypasses eARC and is useful as a diagnostic, although it cannot carry every format.

Format conversion and codec support

The TV can output PCM, Auto or Pass Through depending on firmware and active source. C1/C2-era codec support differs from newer LG models; notably, DTS handling is not something to assume from a current-model guide. A player can decode an unsupported format to compatible PCM, or connect directly to the receiver.

Source and app transitions

Streaming apps often move between stereo menus, Dolby Digital Plus previews and Atmos content. A dropout exactly at a format change may be negotiation rather than bandwidth. Repeated losses during steady playback need a different branch.

CEC competition

Simplink/HDMI-CEC lets devices choose inputs, power states and audio destinations. Multiple boxes may issue conflicting commands on wake. Removing all but TV and audio device is the cleanest way to expose that.

Step-by-Step eARC Fix

1. Establish television audio

Select TV Speakers and replay the known scene. If they also drop, eARC is not the first suspect. Compare another app or source and inspect network playback when streaming. A fault contained in one title should be reported to the provider rather than “fixed” through HDMI settings.

2. Build a two-device system

Disconnect every HDMI source. Connect only the LG eARC port to the receiver/soundbar ARC/eARC port. Enable the documented eARC support and Simplink controls on the television. Use the audio device's TV/eARC input. Confirm ordinary menu sounds or an internal app.

If ARC works but eARC does not, update both devices and check the audio product's exact eARC support. ARC success does not prove its eARC firmware is correct.

3. Begin with PCM

Choose a simple stereo PCM source. If stable, test multichannel PCM where supported, then Dolby Digital Plus/Atmos streaming, and finally a lossless disc path if required. Note the first format that fails. This is more useful than cycling Auto and Pass Through without knowing what the source emits.

Pass Through is appropriate when the downstream device can decode the incoming codec. PCM delegates decoding upstream. Neither is universally best; compatibility and desired channel layout decide.

4. Inspect cable and connectors

Reseat both ends with power off. Test a short certified cable appropriate for the HDMI generation. Avoid tight bends and adapters for the baseline. If the cable is in-wall or long, use a temporary short run before opening walls or replacing equipment.

5. Update and cold-start in order

Record LG, receiver and soundbar firmware versions. Install stable public updates. Power all components down, disconnect briefly where permitted, start the TV and audio device, wait for eARC recognition, then add the source. A restart is a diagnostic; if it must be repeated daily, capture that pattern for vendor support.

6. Add HDMI sources individually

Reconnect one console or streamer, test standby and input switching, then add the next. If a particular device causes the TV to abandon eARC or choose its speakers, examine that device's CEC power and audio-control settings. Disable only the conflicting CEC function if possible rather than losing all control.

7. Test direct-to-receiver routing

For a disc player or streamer, connect it directly to the receiver and send video onward to the TV. If audio becomes stable, the return path or TV pass-through is implicated. This topology may not support every 4K120/VRR format on an older receiver, so consoles may still need direct TV video with eARC audio.

C1/C2 Format Caveats

C1/G1 use the 2021 webOS audio menus; C2/G2 use the 2022 organization. Labels for Digital Sound Output, eARC Support and Pass Through can move. Follow the description on the installed firmware and verify the receiver display.

An Xbox or PC can output multichannel uncompressed PCM, Dolby formats and application-specific bitstreams. PS5 settings distinguish the HDMI device type and preferred format. Do not select an AVR channel layout when the console is actually connected to a two-channel soundbar unless its documentation requires that topology.

Lip-sync delay is independent from dropouts. Adjusting AV Sync may align continuous audio but cannot restore a broken eARC link. Likewise, changing picture mode should not be credited with an audio repair unless video processing demonstrably changes the source timing.

When Not to Reset the TV

Avoid a factory reset until the two-device, PCM and direct-routing tests are complete. Resetting deletes apps, network and picture profiles while leaving a bad cable or receiver bug untouched.

Do not assume every absence of DTS or lossless Atmos is a dropout. First confirm that C1/C2, source app and audio device support the codec and transport. Streaming Atmos normally uses Dolby Digital Plus; disc TrueHD requires a different path.

Contact LG when internal apps repeatedly lose supported audio over multiple known-good eARC devices/cables after firmware updates. Contact the audio manufacturer when TV speakers remain stable and only its product loses lock. Provide timestamps, codec transitions, firmware and simplified wiring diagram.

HDMI Licensing Administrator — Enhanced Audio Return Channel

LG — Troubleshooting no audio from an LG TV

Dolby — Dolby Atmos home theater setup guide

Xbox — Choosing speaker audio output

Reddit — LG C1 owner reports of eARC dropouts