Because of the difference in size between the eardrum and the base of the stapes and the extra leverage in the ossicles the pressure at the cochlea is 17×1.3=22 times the pressure on the e...Because of the difference in size between the eardrum and the base of the stapes and the extra leverage in the ossicles the pressure at the cochlea is 17×1.3=22 times the pressure on the eardrum. Sharp clicking sounds can be presented to the ear (including the ears of babies and children too young to respond to a hearing test) and if the ear is working correctly, there will be a sound response coming from back from the ear that can be detected with a small microphone near the ear.
