Abstract:

Elko previously established the performance improvement for intensity measurements of an acoustic sensor using two microphones embedded on the surface of a hard sphere to that of a sensor comprising two infinitely small microphones separated in space [G. Elko, Noise-Con 91, pp. 525--532]. Elko derived his results for perfectly matched microphones, with regard to phase and sensitivity, in a plane-wave field with a variable angle of incidence. The performance of a spherical sensor and a two-point sensor are compared here for the case of a one-dimensional standing wave field with an arbitrary reflection coefficient and incidence angle, when the measurement microphones have a phase and sensitivity mismatch. Results are generated using sensitivity and phase variations typically found in inexpensive electret microphones. The effect of bias errors in potential energy density, kinetic energy density, total energy density, and intensity are reported.