A communication device comprising an acoustic system and a housing , the acoustic system comprising a transducer and a microphone located in an enclosure of the housing , the enclosure providing a single inward recess in a front face of the housing and including a single cavity located on a top side of the enclosure, the enclosure defining a first location for the placement of the transducer and a second location for the placement of the microphone adjacent to the transducer , and the acoustic system further comprising a grill placed in the cavity , wherein: the single cavity is defined by and extending continuously between sidewalls inwardly extending from the face of the housing and a bottom formed by the housing ; a first port extends from the bottom of the cavity and connects the first location to the cavity to provide a direct first acoustic channel from the transducer to the cavity , and a second port extends from the bottom of the cavity and connects the second location to the cavity to provide a direct second acoustic channel from the microphone to the cavity , wherein the second acoustic channel is separated from the first acoustic channel and the first port connects to the cavity beside the second port ; and the grill covers the first port and the second port ; characterized in that : the grill is configured to leave a free space within the cavity between the bottom of the cavity and the grill so as to allow some components of output sounds generated by the transducer to directly reach through the free space the second port from the first port ; and said acoustic system is further configured as a feedback system for adjusting the output sounds generated by the transducer using input signals received from the microphone . the single cavity is defined by and extending continuously between sidewalls inwardly extending from the face of the housing and a bottom formed by the housing ; a first port extends from the bottom of the cavity and connects the first location to the cavity to provide a direct first acoustic channel from the transducer to the cavity , and a second port extends from the bottom of the cavity and connects the second location to the cavity to provide a direct second acoustic channel from the microphone to the cavity , wherein the second acoustic channel is separated from the first acoustic channel and the first port connects to the cavity beside the second port ; and the grill covers the first port and the second port ; characterized in that : the grill is configured to leave a free space within the cavity between the bottom of the cavity and the grill so as to allow some components of output sounds generated by the transducer to directly reach through the free space the second port from the first port ; and said acoustic system is further configured as a feedback system for adjusting the output sounds generated by the transducer using input signals received from the microphone . the grill is configured to leave a free space within the cavity between the bottom of the cavity and the grill so as to allow some components of output sounds generated by the transducer to directly reach through the free space the second port from the first port ; and said acoustic system is further configured as a feedback system for adjusting the output sounds generated by the transducer using input signals received from the microphone . <EOS>