Probes Design and Experimental Measurement of Acoustic Radiation Resistance

Abstract

An experimental method used to measure radiation resistance was developed, which was based on a lumped parameter model. Three probes (devices for measuring acoustical radiation resistance) were designed, and the test system was built. To verify the accuracy of the experimental results and to find the application frequencies range for each of the probes, self-resistance and cross-resistance measurements of baffled circular pistons were conducted. The results show that this method is a practical way to obtain the acoustical resistance and that the probe with a 57 mm speaker can obtain resistance values in the frequency range from 260 Hz to 1700 Hz. The probe with a 50 mm speaker, on the other hand, presents resistance in the frequency range from 460 Hz to 1900 Hz; the range of 700 Hz to 2600 Hz is for the probe with a 40 mm loudspeaker. To verify the actual application effects, experiments measuring the resistance of a horn were performed. The results show that the measuring system with three probes can be used to predict acoustical resistance of various structures with high accuracy in a convenient and simple way.