There are several wav files in the Sound folder for different "classes" of ship. If you take the Corvette sounds, there's "Corvette.wav" for 'normal' listening, a "Corvette_hyd.wav" for close underwater, a "Corvette_Low.wav" for being away further, and a "Corvette_mix.wav". There's BBKingGeorge (or whatever) that most of the bigger capital ships use, a DD of some sort for the medium sized ones, that corvette wave, several for Merchants, etc. Not one file for each ship, but one shared between the groups... They run the SH.SDL for volume control, however, that has nothing to do with the sonar detection. Only your ears perception of the physical sound.
