A mobile communication apparatus for adjusting at least a physical property of an acoustic signal , comprising - a ringtone generator means adapted to generate the acoustic signal , - processing means in signal communication with said ringtone generator means , - ultrasound receiver means apt to receive at least an ultrasonic signal generated by an accessory device , said ultrasonic signal carrying a measure of a property of the ambient noise, which is picked up by a microphone of the adjustment accessory , wherein the processing means are configured for a. detecting at least a physical parameter and/or decoding at least a content of said at least one ultrasonic signal received through the ultrasound receiver means , b. determining, on the basis of said at least one physical parameter and/or content of said at least one ultrasonic signal , attenuation information that can quantify the attenuation suffered by the ultrasonic signal and/or allow an assessment of the attenuation suffered by the acoustic signal along a propagation path, c. determining, on the basis of said attenuation information, said at least one physical property of the acoustic signal , and d. generating, through said ringtone generator means , said acoustic signal having said at least determined physical property, said apparatus further comprising transmission means for requesting emissions of ultrasonic signals to the accessory device that is configured for emitting the ultrasonic signal on request, and wherein the processing means are also configured for requesting, through said transmission means, an emission of said ultrasonic signal , said apparatus further comprising audio input means in signal communication with the processing means , and wherein the processing means are configured for - detecting, by means of the audio input means, at least a variations of at least a property of the ambient acoustic noise around said apparatus, and - requesting, through said transmission means, at least an emission of said ultrasonic signal when said at least one variations of said at least one property of the ambient acoustic noise is detected. - a ringtone generator means adapted to generate the acoustic signal , - processing means in signal communication with said ringtone generator means , - ultrasound receiver means apt to receive at least an ultrasonic signal generated by an accessory device , said ultrasonic signal carrying a measure of a property of the ambient noise, which is picked up by a microphone of the adjustment accessory , a. detecting at least a physical parameter and/or decoding at least a content of said at least one ultrasonic signal received through the ultrasound receiver means , b. determining, on the basis of said at least one physical parameter and/or content of said at least one ultrasonic signal , attenuation information that can quantify the attenuation suffered by the ultrasonic signal and/or allow an assessment of the attenuation suffered by the acoustic signal along a propagation path, c. determining, on the basis of said attenuation information, said at least one physical property of the acoustic signal , and d. generating, through said ringtone generator means , said acoustic signal having said at least determined physical property, - detecting, by means of the audio input means, at least a variations of at least a property of the ambient acoustic noise around said apparatus, and - requesting, through said transmission means, at least an emission of said ultrasonic signal when said at least one variations of said at least one property of the ambient acoustic noise is detected. <EOS>