When the torpedos shoot out of the "Nerka", it sounds like cymbals and tympani crashing.
Torpedos are forced out of the tube by compressed air when they're fired, so the sound you heard was the sound of the air blasting out of the tube.
shareMany Former Submariners reported the sound as a whoosh of compressed air followed by the high pitched whine of the propellors activated. There was also an associated ear-popping rise in pressure each time a Fish was fired as a popit valve was opened and the air that fired the Torpedo was bled back into the boat to prevent the bubbles from rising to the surface.
After a prolonged submergence and multiple torpedo firings, along with depth changes that required recompensation of bouyancy... the Air Pressure inside a boat could be dangerously higher than sealevel pressure on the surface. Care had to be taken on surfacing the boat to bleed off that pressure before just opening the hatch.
It has been recorded where sailors popping the hatch have been blasted clear out the hatch and over the side from the pressure differential.
(Source: CDR Richard O'Kane's Biographical book "Clear The Bridge" The Five war patrols of USS Tang.)
I joined the Navy to see the world, only to discover the world is 2/3 water!