Transfer matrix modeling of a recessed microphone for unsteady surface pressure measurements

Recessed microphones are commonly used for unsteady surface pressure measurements, either due to space limitations or to satisfy performance requirements. A technique is developed using transfer matrices to design a configuration by modeling its frequency response. This technique is beneficial since it provides guidance to optimize the recessed configuration prior to fabrication. The recessed nature also allows for utilization of closely-spaced pressure ports on a surface, thus providing an inexpensive means for measuring unsteady surface pressures with high spatial resolution. A tube-branch design capable of achieving a 10-kHz bandwidth is presented and validated experimentally using an acoustic plane wave tube.