A Method for Determining Frequency Response of Microphones in Unmuffled Laboratory Room Using Wideband Signal Excitement

Abstract

The paper introduces a method for determining the frequency response of microphones using a broadband excitation signal. The method is based on time deiay spectrometry and uses the recursive filter of the Goertzel algorithm and additional sliding complex weighted averaging under conditions burdened by sound reverberation. A combination of field and pressure measurements was used to minimize the effect of reflections during measurements. Relying on the algorithm, we developed software for post-processing the measurement results when determining the frequency response of microphones in an unmuffled laboratory room. Furthermore, we assembled a research measuring complex and experimentally tested the developed method and software determining the methodical error in the frequency response of microphones using a broadband excitation signal. The developed method and software are recommended for determining the frequency response of measuring microphones by the field in unmuffled reverberating laboratory rooms without auxiliary equipment, such as a damped chamber and a small-volume chamber, provided the practical recommendations given in the research are taken into consideration