Disabling the Default Audio Device in ChromeOS for External USB Headsets

If you frequently use Chrome OS and connect external USB headsets, you might experience issues with Chrome OS switching the default audio device to the built-in audio whenever a user logs in. This article will guide you through disabling the default audio device, so your external USB headsets function correctly without the need to switch the audio device every time.

Background

Chrome OS is a lightweight, versatile, and secure operating system developed by Google. Its simplicity, built-in security features, and fast boot times make Chrome OS an excellent choice for users who need a reliable device for browsing, productivity, and lightweight tasks.

Default Audio Device Settings

Whenever an external USB headset or audio device is connected to a Chrome OS device, the operating system automatically switches the default audio device. However, on a subsequent login, Chrome OS reverts to the built-in audio device as the default.

Disabling Default Audio Device on Chrome OS

In this section, we will walk through the steps required to disable the default audio device on your Chrome OS device.

Using the Chrome OS Developer Mode

To disable the default audio device, you must enable the Chrome OS Developer Mode, which allows you to access the underlying system files. Before proceeding, remember that enabling Developer Mode may affect your device's security and performance.

Enabling Developer Mode

To enable Developer Mode, follow these steps:

1. Press Esc + Refresh (F3) keys while powering on your device.
2. When you see the red exclamation mark, press Ctrl + D to enable Developer Mode.

Note: Enabling Developer Mode will wipe all your local data. Be sure to back up any critical files before proceeding!

Disabling the Default Audio Device

To disable the default audio device, follow these steps:

1. After enabling Developer Mode, open the Terminal by pressing Ctrl + Alt + T.
2. To access the root shell, enter the following command:

   sudo su

   You will be prompted to enter your user password.

3. Enter the following command to edit the configuration file for audio devices:

   nano /etc/chromeos-platform/sound/platform_sound.conf

   This will open the configuration file in the Nano text editor.

4. Locate the following section in the configuration file:

   <match name="system"> <attribute name="output_name">internal-speaker</attribute> </match>

5. Replace the value of the output\_name attribute from internal-speaker to duplex. Your updated section should look like this:

   <match name="system"> <attribute name="output\_name">duplex</attribute> </match>

6. Press Ctrl + X to exit the Nano text editor. Confirm the changes you made by pressing Y and then press Enter to save and quit.
7. To apply the new configuration settings, restart your device by entering the following command:

   reboot

Upon restarting the device, the default audio device should be set to duplex. Connect your USB headset, and Chrome OS should now maintain the headset as the default audio device.

• Chrome OS has a default behavior of switching back to the built-in audio device after logging out or rebooting the system.
• To prevent this behavior, the Chrome OS Developer Mode must be enabled, and the system configuration file platform\_sound.conf must be updated.
• The output\_name attribute of the system match section should be changed from internal-speaker to duplex in the configuration file.
• After making the changes, restart the device for the new settings to take effect.

References

• Chromium OS Developer Information
• Chrome OS System Requirements
• Chromium OS Sound Troubleshooting