Ratio of tympanic members to oval window is

According to some workers (Wever and Lawrence) out of a total of 90 mm2 area of human tympanic membrane, only 55 mm2 is functional and given the area of stapes footplate (3.2 mm2), the areal ratio is 17:1 and total transformer ratio (17x 1.3) is 22.1. Ref: Dhingra 7e pg 17.