A device and a process for analysis of acoustic reflectance of components of an ear directs into the ear canal acoustic waves covering a range of frequencies including resonance frequencies of ear components such as the tympanic membrane. Measurements are made without pressurizing the ear canal...http://www.google.com/patents/US5699809?utm_source=gb-gplus-sharePatent US5699809 - Device and process for generating and measuring the shape of an acoustic reflectance curve of an ear 
