MacBook Air M1: No sound from external speakers via monitor

Hi there,

Here are a few steps to check when audio is not playing through external speakers connected to an LG UHD IPS monitor after a macOS update:

1. Select the correct audio output

Go to  → System Settings → Sound → Output and choose the LG monitor (may appear as “LG…”, “USB-C”, or “DisplayPort”).

Apple guide: Change the sound output settings on Mac - Apple Support (CA)

2. Check the monitor’s audio settings

In the LG on-screen menu, confirm:

• Audio Out is set to Line Out or Headphones
• Volume is enabled
• Speakers are connected to the correct port

3. Reconnect the USB-C cable

Unplug the cable for about 10 seconds and reconnect it to re-establish audio routing.

4. Restart Mac audio

Open Terminal and run:

sudo killall coreaudiod

5. Check Audio MIDI Setup

Open Applications → Utilities → Audio MIDI Setup and set the monitor to 48,000 Hz, 2-channel.

Apples guide: Set up audio devices in Audio MIDI Setup on Mac - Apple Support (CA)

Thanks for the update. Since the apps freeze as soon as the LG monitor is selected, that usually means the audio stream isn’t initializing correctly. Here are a few quick things to try next:

1. Fully shut down the Mac (not Restart)

Power off → wait 10–15 seconds → turn it back on. This forces the audio system to reset.

2. In Audio MIDI Setup

Try switching the LG monitor between 44.1 kHz and 48 kHz. Sometimes the audio format gets stuck after an update.

3. Try a different USB-C cable or port

A cable/port issue can make the display work but cause audio to hang.

4. If possible, test with HDMI

If HDMI audio works, it confirms the issue is specific to USB-C after the macOS update.

Regards.