You can easily adjust the volume by tapping the (+) Button or the (-) Button. You will hear a beep when the volume reaches maximum or minimum level. The volume is set and maintained independently at different levels for each audio source even when you turn off and on the Bluetooth Mic. For example, once you set the volume for a paired mobile phone, it will not change even if you adjust the volume when you hear Bluetooth MP3 music. So you can always maintain the preferred optimum volume level for each audio source.