Basic examinations of the sound transmission loss measurement using two cardioid microphones

This paper reports results of an experiment on sound transmission loss measurement using the C-C method. This method is an inexpensive and stable method for measuring the sound pressure, the particle velocity, and the sound intensity. The measurements are carried out in accordance with JIS A 1441-1:2007 based on ISO 15186-1:2000, and the C-C method is applied for measuring the sound intensity. Comparing the measured results with those of the sound pressure level difference method, comparable results are obtained above 250 Hz. Naturally, the precision of the measurements depends on the microphone calibration used in the C-C method. In this report, we employ two calibration methods using an acoustic tube and an anechoic chamber, and also exhibit comparison of the results obtained by these methods.