Make sure your phone supports LDAC. Android phones prior to version 8.0 and all iOS devices do not support LDAC. 2. LDAC is not the default audio codec. It needs to be set via the soundcore App (2.7.0 and newer versions). - Pair the earbuds with soundcore App. - Select "Sound Quality Mode" in settings. - Select "Preferred Audio Quality". 3. For Samsung S series and Note series users, please select LDAC in your phone's Bluetooth settings before using the LDAC mode.