ERRORS IN THE MEASUREMENT OF ACOUSTIC ENERGY DENSITY IN ONE-DIMENSIONAL SOUND FIELDS

Acoustic energy density has been shown previously to be an effective cost function for active control of noise in enclosed sound fields. Here bias errors in the energy density measurements that occur in one-dimensional sound fields when using the two-microphone technique to estimate the particle velocity are discussed. Four types of bias error for both two- and three-microphone arrangements are investigated; namely, inherent, phase mismatch, sensitivity mismatch and spatial errors.