External-ear acoustic models with simple geometry.

The properties of the human ear are duplicated in simple physical models that may be accurately specified. A shallow cylindrical cavity set in an infinite plane that represents the concha has a depth resonance with values of gain and bandwidth in agreement with those observed in typical real ears under “meatus‐blocked” conditions. To represent the human pinna, a rectangular flange is added to an inclined cylindrical concha. A cylindrical canal with a two‐element network to simulate the eardrum impedance completes the model. Response curves with hard and soft eardrums, measured at eardrum position, at canal entrance and with blocked meatus, all have identical angular dependence up to 7 kHz and very similar angular dependence up to at least 12 kHz. The response of the model with blocked meatus and with open canal is in good agreement with real‐ear data up to 7 kHz at normal and oblique incidence. Pressure distributions in the model ear for the first two modes (M1 and M2) are in excellent agreement with replica data.