Abstract: A pneumatic compression supplies both positive and negative pressure for operating a medical device. The pulsing sounds generated by the compressor are attenuated by connecting the inlet of the positive pressure side of the compressor and the outlet of the negative pressure side of the compressor to a common resonating chamber. A port in the resonating chamber acts as an outlet for the discharge of excess air in the chamber and an inlet for the entry of make-up air. By adjusting the diameter of the port with respect to the volume of the resonating chamber, sound attenuation can be optimized. In a compact design, the compressor housing serves as the resonating chamber.