Abstract: A CPAP system includes a PAP device (5) structured to generate a supply of pressurized air, a patient interface (15) adapted to engage with the patient's face to provide a seal, an air delivery conduit (102,104) provided between the PAP device and the patient interface to deliver the supply of pressurized air along a gas delivery path from the PAP device to the patient interface, and a muffler (100) provided along the gas delivery path downstream of the PAP device.

Abstract: Methods and apparatus provide acoustic detection for automated devices such as respiratory treatment apparatus. In some embodiments of the technology, acoustic analysis of noise or sound pulses, such as a cepstrum analysis, based on signals of a sound sensor (104) permits detection of obstruction (O) such as within a patient interface, mask or respiratory conduit (108) or within patient respiratory system. Some embodiments further permit detection of accessories such as an identification thereof or a condition of use thereof, such as a leak. Still further embodiments of the technology permit the detection of a patient or user who is intended to use the automated device.