When the channel level is raised while the AUX jack is not being used, you may hear white noise in the headphones. When you aren’t using the AUX jack, set the channel level to minimum, or mute the sound.
Noise picked up by the microphone (background noise) can be suppressed using the noise suppressor function. Set the noise suppressor to ON. If noise is still heard even when the noise suppressor is ON, adjust the settings of the noise suppressor parameters. For more details about the noise suppressor parameters, refer to the BRIDGE CAST Owner's Manual under “Calibrating the Mic Sound Quality (Cleanup).”