Abstract: A mobile radio device is disclosed that includes a microphone and a loudspeaker, wherein said loudspeaker (LP) is adapted for sound reproduction in the hands-free mode and/or for call signaling. The device is provided with a unit to acoustically measure the distance between the loudspeaker and an obstacle, the distance measured by measuring the propagation time of the test sound. The call signal volume or hands-free volume is controlled in accordance with the propagation time measured. Additionally, the output volume on the loudspeaker can be controlled in accordance with the measured volume of the reflected test sound.