The anatomy of the middle ear was transformed into a mechanical model, using masses, springs, frictional constants, etc. From this, mathematical equations describing the action of the middle ear were derived and the frequencies of free vibration of the middle ear elements were computed and then detd. experimentally. From the results, the following conclusions are drawn: the middle ear has 4 main peaks of resonance; the middle ear and cochlea appear to be a displacement receiver and a pressure receiver, respectively; the tympanic membrane composes the vibrations of the external auditory canal, the antrum, and the air cells of the mastoid process and propagates these vibrations to the ossicles; nonlinear vibrations of the tympanic membrane and basilar membrane produce combination tones; the air vibration system of the external auditory canal, the antrum and the tympanic cavity magnifies the intensity of speech sounds.