Variability of SCUBA diver's acoustic emission

Knowledge of the variability of the acoustic emission characteristics from SCUBA divers is critically important for designing and operating a passive acoustic SCUBA characterization system. Using modeling and experimental measurements in a controlled environment, we identified key source factors influencing the variability of the acoustic emission parameters including Source Band Level (SBL), Spectral Power Density (SPD), and breathing periodicity or emission modulation frequency. The key factors are: equipment, specifically, the design of the first stage (high pressure) regulator and its service life; diver's experience and training; and, finally, operating conditions of the equipment and diver, i.e. tank air pressure and the diver's motion activity. We found, for example, that the SBL could vary as much as 16 dB depending on the equipment used and up to 15 dB depending on the diver's intensity of motion.