Audio lag or lip-sync issues on your LG NanoCell NANO90 can ruin your viewing experience, making movies unwatchable and dialogue frustrating to follow. Whether the sound arrives before the picture or trails behind it, this guide walks you through proven fixes for LG NanoCell NANO90 sound not synced problems. These solutions work for built-in speakers, soundbars, and external audio systems.
Quick Audio Sync Adjustments on Your LG NanoCell NANO90
Start with the simplest fixes that resolve most LG NanoCell NANO90 sound not synced issues without extra equipment or complex setup.
1
Access the Sound Settings Menu: Press the Settings button on your LG Magic Remote, navigate to All Settings > Sound > Additional Settings. Look for the "AV Sync Adjustment" or "Audio Delay" option, which lets you manually shift audio timing forward or backward in millisecond increments.
2
Enable Automatic AV Sync: In the same Additional Settings menu, turn on "Auto AV Sync" if available on your NANO90 firmware version. This feature uses HDMI-CEC communication to automatically align audio with video when connected to compatible devices like LG soundbars or receivers.
3
Test with Built-In Speakers First: Temporarily disconnect all external audio devices and test the NANO90's internal speakers. If sync issues disappear, the problem stems from your external audio chain rather than the TV itself, narrowing your troubleshooting focus.
4
Adjust Lip Sync Per Input Source: The LG NanoCell NANO90 stores audio delay settings per HDMI port and app. Switch to the problematic input (streaming app, HDMI 1, HDMI 2, etc.) and set a custom AV Sync value. Try increments of 20ms—positive values delay audio, negative values advance it relative to video.
Fixing Sound Sync with External Audio Devices
Soundbars, receivers, and home theater systems introduce additional processing that commonly causes LG NanoCell NANO90 sound not synced scenarios. These steps target those configurations.
5
Enable HDMI-CEC (SimpLink) on All Devices: On your NANO90, go to All Settings > General > Devices > HDMI Settings and ensure SimpLink is turned on. Then activate CEC (often called Anynet+, BRAVIA Sync, or similar) on your soundbar or receiver. This allows devices to negotiate timing automatically.
6
Switch to PCM Audio Output Temporarily: Navigate to All Settings > Sound > Sound Out > Optical/HDMI ARC and change "Digital Sound Out" from "Auto" or "Pass Through" to "PCM." While this disables surround sound formats, it eliminates processing delays that cause sync issues, helping identify whether your receiver or soundbar is the bottleneck.
7
Update Firmware on All Connected Devices: Check for TV updates at All Settings > General > About This TV > Check for Updates. Then update your soundbar or receiver firmware through its respective app or settings menu. Manufacturers regularly release patches addressing HDMI timing and lip-sync bugs.
Warning: Do not factory reset your LG NanoCell NANO90 as a first troubleshooting step. This erases all account logins, app data, and picture settings. Exhaust targeted audio and connectivity fixes before considering a full reset, and document your current picture settings if you proceed.
Advanced Troubleshooting for Persistent Sync Problems
If basic adjustments don't resolve your LG NanoCell NANO90 sound not synced issue, deeper configuration changes or hardware checks may be necessary.
8
Disable Motion Enhancement Features: Go to All Settings > Picture > Picture Mode Settings > TruMotion and set it to "Off" or "User Selection" with both De-Judder and De-Blur at 0. Motion interpolation adds video processing delay that can throw audio out of alignment, especially noticeable with 24fps film content.
9
Test Different HDMI Ports and Cables: Connect your external audio device or source to a different HDMI port on the NANO90. Use certified Premium High Speed HDMI cables (HDMI 2.1 for 4K/120Hz sources). Damaged or underspecified cables cause signal timing irregularities that manifest as audio drift.
10
Reset Audio Settings to Default: Navigate to All Settings > Sound > Reset to Initial Settings. This clears any accumulated custom delays or output configurations while preserving your picture and network settings. Reconfigure your preferred sound output method afterward and retest sync.
Frequently Asked Questions
Why does the LG NanoCell NANO90 sound not synced only happen with streaming apps?
Streaming apps process audio and video separately, and buffering differences can create sync drift. Force-close the problematic app, restart your NANO90, and ensure your internet connection exceeds 25 Mbps for 4K content. Some apps also have their own audio sync settings in their playback menus.
Can a soundbar cause permanent audio delay on the NANO90?
Most soundbar delays are correctable. Check if your soundbar has its own "AV Sync," "Audio Delay," or "Lip Sync" adjustment in its companion app or physical remote. Set the soundbar to minimal processing (direct or bypass mode) and handle all delay compensation through the TV's AV Sync menu for centralized control.
Does eARC on the NANO90 improve audio synchronization?
Yes. The LG NanoCell NANO90 supports eARC (enhanced Audio Return Channel) on HDMI 2, which handles uncompressed surround sound with better timing precision than standard ARC. Ensure both your TV and audio device use eARC-enabled ports, and enable eARC in the TV's HDMI settings for optimal sync with Dolby Atmos and DTS:X content.
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