Annoying super rapid torpedo pinging

[Castout]

I just had a weird experience that an enemy torpedoe, well there were actually two torpedoes but only one seemed to be heading my way while the other was oblivious to my presence, anyway that one torpedo pings so rapidly like it was mere few feet from me which is ridiculous and not to mention very annoying.

Does anybody know why is this happening(very rapid pinging). I know that the closer the torpedo gets the more rapid is its pinging but this one is so rapid thus becoming very ridiculous. It's not that rapid all the time but when the torpedo is heading my way it gets very rapid but the distance was still at least 1.5 to 2 nm away.

Latest LWAMI 3.08 installed and the improved sound mod from subguru.

And the torpedoes were fired from a Trafalgar sub. Perhpas this would give some clue?