The present invention is related to a device for acoustically monitoring a subject’s airway to determine airway obstruc­tion( s) and their location(s ). The device is particularly useful when performing sleep analysis and sleep therapy, but is also highly useful in determining airway obstructions of any subject when the subject is sleeping or otherwise uncon­scious, and can further be used in certain applications when the subject is awake or conscious. The device, in its simplest form, is comprised of a supporting body ( e.g. a mask, mouthpiece, or nasal cannula) used to position at least one acoustic generator and at least one acoustic sensor at a location essentially proximal to a subject’s airway, the acoustic generator and acoustic sensor generating and/or sensing sound waves useful in determining obstruction(s) and their location(s) within the airway of a subject.