Response of an edge-supported circular membrane electret earphone. Part I—Theory

The behavior of an edge-supported circular membrane foil electret earphone is studied in a three-step analytical procedure. First, the static deflection is determined for a specified set of transducer parameters. The deflection is expressed as a power series in radial location. Second, the dynamic deflection, which depends on the static deflection, is found. It is also expressed as a power series in radial location. Third, the linear dynamic response is examined to determine a procedure for maximizing the sound pressure level which is generated in the ear. The results presented here indicate that with the choice of an optimum set of earphone parameters it is possible to construct an earphone with a sensitivity of 82 dB/V and a relative distortion level of about −40 dB.