In this paper, a method of measuring the input mechanical impedance of the array element (longitudinal vibrating transducer) with square radiation head by using impulse sound tube is proposed.

The effects on the underwater sound attenuation by the thickness and concentration gradient of polymers were measured in a sound tube at different frequency during the polymers dissolution process.

Fans cooling the transmitter wailed with a sound like a high-powered leaf blower — and the thermometer inside the tube began to climb.