Further developments in the active control of free‐field sound using near‐field energy‐based error signals

Abstract

Practical efforts to actively control sound often require error sensors located in the acoustic or geometric near field of sound sources. Unfortunately, when using conventional acoustic pressure sensors, control performance often becomes very sensitive to sensor location. Optimal sensor positions are difficult to ascertain or maintain with changing system conditions. Alternate types of error sensors often lead to fewer position‐dependent complications, producing global sound field control with greater ease and consistency. The distinct spatial and spectral uniformities of potential, kinetic, and total energy density for near‐field error signal measurements will be discussed for the sound control of sources located in a free field. Numerical results will be compared to experimentally measured results.