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Increased emphasis toward the development of new microphones for measurements at high acoustic pressure occurring in sonic-boom phenomena, flight-vehicle noise, and shock-wave studies has necessitated continued development of devices and methods to measure and calibrate these transducers. Since each method has its limitations with regard to pressure, frequency, and accuracy, it is necessary to apply several calibration methods for evaluation and calibration of pressure transducers. From the great number of calibration devices available, the pistonphone is the apparatus that delivers an absolute calibration of high accuracy in the pressure range up to 185 dB (re 10−4 dyn/cm2). Its application at high pressure and frequency is limited owing to nonlinearity characteristics of the gas, which leads to a distortion of the waveform applied. A high-intensity pistonphone has been developed; its theoretical aspects are described and compared with experimental results. It operates in the range from 5 to 200 cps at sound-pressure levels from 134 to 185 dB. A number of measurements showing nonlinearity, hysteresis effects, and repeatability of sensitivity are described.
Dahlke et al. (Tue,) studied this question.