The Bluetooth headphones (earbuds) volume does not increase or sync with the smartphone volume

For LinkBuds Clip (WF-LC900):

Refer to the following article: LinkBuds Clip (WF-LC900)

For other earbud models:

For other models, follow these steps to troubleshoot the issue:

• Depending on the connected device, the volume may not sync with the earbuds and you may not get the desired volume. For best results, adjust the volume on both the earbuds and the connected device.

  Note: If you are using the Sony | Sound Connect app, adjust the volume in the app and on the connected device.

• If your earbuds are In-Ear or Truly Wireless models, make sure the earbuds fit your ears properly. If they do not, the volume may seem low.

  Note: The best earbud size may be different for each ear. Use the size that fits best according to each ear. For information on how to wear the earbuds properly or how to change them, refer to the product manual or Help Guide.