The LG C3 and C4 are excellent OLED TVs, but their built-in speakers cannot do justice to the picture quality. Adding a Dolby Atmos soundbar over eARC is the fastest way to transform your viewing experience. Here is what to look for, how to set it up, and which soundbars work best with LG OLEDs.
Quick answer
- Get a soundbar with eARC and Dolby Atmos — This ensures full-quality audio passthrough from LG C3/C4 built-in apps
- Use HDMI 3 on your LG C3/C4 — This is the eARC port on LG OLED TVs
- Connect with a certified HDMI 2.1 cable — eARC needs 48Gbps bandwidth for Dolby Atmos
- LG soundbars have the fewest compatibility issues — LG's WOWCAST and Synergy features optimize the pairing
What to look for in a soundbar
eARC support (mandatory) Your LG C3/C4 outputs Dolby Atmos from built-in apps through eARC. A soundbar that only supports standard ARC will downgrade Atmos to basic Dolby Digital, losing the immersive overhead effects.
Dolby Atmos decoding The soundbar must decode Dolby Atmos, not just pass it through. Look for upward-firing speakers or dedicated height channels — these create the overhead sound effects that make Atmos content immersive.
HDMI 2.1 passthrough (for gamers) If you connect a PS5 or Xbox to the soundbar, it needs HDMI 2.1 inputs with 4K 120Hz passthrough, VRR, and ALLM. Without this, plug consoles directly into the TV and use eARC for audio only.
Wireless subwoofer Soundbars alone cannot produce deep bass. A soundbar with an included wireless subwoofer fills in the low frequencies that make action movies and music feel powerful.
How to set up your soundbar with LG C3/C4
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Connect the soundbar to HDMI 3 (eARC) Use a certified Ultra High Speed HDMI cable. Plug one end into the soundbar's HDMI OUT (ARC) port and the other into HDMI 3 on your LG C3/C4.
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Power on the TV, then the soundbar Let the LG C3/C4 boot to webOS, then turn on the soundbar.
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Set audio output Settings → Sound → Audio Output → select "HDMI ARC." The soundbar should appear as the active audio device.
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Enable eARC Settings → Sound → Additional Settings → eARC → On. This ensures uncompressed Dolby Atmos passes to the soundbar.
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Set digital audio format Settings → Sound → Additional Settings → Digital Sound Out → "Auto" or "Pass Through." Pass Through sends the original audio stream to the soundbar for decoding.
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Test Dolby Atmos content Play a Dolby Atmos movie on Netflix or Disney+ (look for the Atmos badge). The soundbar should display "Dolby Atmos" or "Atmos" on its front panel.
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Adjust sound settings Use the soundbar's remote or app to adjust EQ, subwoofer level, and center channel volume to your preference.
LG C3/C4 specific tips
- Turn off TV speakers — Settings → Sound → Audio Output should be "HDMI ARC," not "TV Speaker + HDMI ARC" (the combined mode adds delay)
- Disable AI Sound Pro — Settings → Sound → AI Sound Pro → Off. This TV processing can conflict with the soundbar's own processing
- Use Sound Mode on the soundbar — Let the soundbar handle sound modes (Movie, Music, etc.) rather than using the TV's sound settings
- Match Content on — Settings → General → AI Service → AI Picture Pro → Match Content → enables the TV to signal content type to the soundbar
Troubleshooting
No audio from soundbar — Power cycle both devices, disconnect and reconnect the HDMI cable, and verify eARC is enabled on the TV. See our full guide: LG C3 + soundbar eARC no sound or cutouts.
Dolby Atmos not showing on soundbar — Make sure Digital Sound Out is set to "Pass Through" not "Auto." Auto sometimes downmixes Atmos to Dolby Digital.
Lip sync issues — Settings → Sound → Additional Settings → AV Sync Adjustment → adjust until audio matches video. A value of 10-30ms is typical.
Audio drops during gaming — If gaming at 4K 120Hz causes audio dropouts, try connecting the console directly to the TV instead of through the soundbar. Use eARC for audio from TV to soundbar.
Looking to Upgrade Your LG TV Audio?
If LG audio or eARC issues keep coming back, our best soundbars for LG TVs guide covers the top picks — including which LG soundbars support WOW Orchestra (combining TV speakers with the soundbar) and which third-party options have the most reliable eARC performance with LG's implementation.
FAQ
Does it matter if I get an LG soundbar vs. another brand? LG soundbars integrate best with LG TVs. Features like WOWCAST wireless connection, Synergy mode (which combines TV and soundbar speakers), and seamless volume control work only with LG-to-LG. However, Samsung, Sonos, Sony, and JBL soundbars all work well with LG TVs over standard eARC.
Do I need a 5.1 or 7.1 soundbar? For most living rooms, a 3.1.2 or 5.1.2 system is ideal. The ".2" means two upward-firing Atmos speakers. A 7.1 or higher system adds rear surround speakers, which is worth it for dedicated home theaters but overkill for casual viewing.
Can I add rear speakers later? Many soundbar systems (LG, Samsung, Sonos) let you add wireless rear speakers after purchase. This is a good way to start with a soundbar + subwoofer and upgrade to full surround later.
Will the soundbar improve dialogue clarity? Yes, significantly. Soundbars with a dedicated center channel speaker are much better at reproducing dialogue than TV speakers. Look for a 3.1 or higher channel configuration.