Improved method for sound velocity measurement with frequency response under atmospheric pressure

Based on the characteristics of frequency responses at different positions, a new method of sound velocity measurement in a sound tube is suggested to get more stable sound velocity. Two hydrophones with moderate distance are adopted for measuring sensors, and it does not need to change the position of the water surface and the sensor position. The operation of the experiment is simple, and the data processing is easy. The fluctuation of frequency differences is small. It can be used in the condition that pressure exists. The influence of the reflection coefficient of the transmitting transducer on the bottom of the sound tube is eliminated. As a result, more accurate sound velocity is obtained. Simulation results demonstrate the periodicity of the function and the stability of the frequency differences. The accuracy and reliability of this method are proved by the experiment's results. The local sound velocity can be measured correctly with the frequency response. This method offers an accurate reference for the sound tube measurement system. The precision of the measurement can be ensured.