The Design of the Mammalian Auditory System: A Brief Overview

Abstract

There are three stages in sound reception at the periphery. First, sound reaches the external ear, or pinna, where, owing to the difference in acoustic impedance between air and tissue, most of the sound energy is dissipated by reflection. The sound entering the ear canal will be amplified to an extent dependent on the direction of incident sound waves in relation to the acoustical axis of the pinna. Thus, the pinna acts as a directional (and, for some species, highly mobile) sound amplifier.