Spheres for calibrating an eleven-frequency acoustic measurement system

Abstract

Calibration of a single resonant transducer by standard sphere is a\nsimple matter. How does one calibrate an array composed of eleven\ndifferent resonant transducers spanning the frequency range from 27 to 710\nkHz? A solution is given by specifying the diameters and target strengths\nof four precision ball bearings made from tungsten carbide with 6% cobalt\nbinder.