Acoustic sleeve for telephone receiver and mobile telephones

摘要

The acoustic sleeve includes perforations on the entire front surface or at least at the microphone and loudspeaker area of the telephone. The perforations have the same opening diameters as the holes of the telephone receiver. The front outer side is transparent or non-transparent. A napped chemical pulp or plastics insert is provided on the inner side of the sleeve for damping the resonance and shielding disturbing ambient noise. Alternatively the inner side can be deadened or coated.