I'm specifically thinking of this scene of the movie Das Boot. The crew seems to be able to hear the ping sound coming from British destroyers without using a hydrophone or SONAR headphones. Is this historically accurate?
In short, yes. Sound propagates very well through the water compared to air. ASDIC was initially designed to work in a 14-22 KHz range, with 20 KHz being the high end of normal human hearing. Hydrophones can help you determine the direction of incoming sonar, and can also help the submarine detect own ship's sound transients (improperly operating equipment, sailors dropping wrenches in the bilges). As a submariner myself, I have firsthand experience of trying to go to sleep and hearing another ship's sonar through the hull. I have even heard whales through the hull, although I am sure someone in the sonar shack heard them a lot clearer than I did.
This is how an ASDIC ping sounds through an WW2 submarine sonar: http://www.hnsa.org/sound/soundinthesea/track30.mp3
JP Sonar Training Records: The JP was the most important and most frequently used submarine passive sonar used during WW II. These 78-RPM training records were created for the Bureau of Naval Personnel by Columbia University - Division of War Research at the U.S. Navy Underwater Sound Laboratory, Fort Trumbul, New London, Connecticut.
These declassified sounds from the USN were collected together by sonar development company in the 1960s.
However there is no recording of the ping from within the submarine hull outside the sonar station. :(
From what I've read, it wasn't quite as clear as the crisp "ping" in the movies. I heard a recording a long time ago from a training exercise on an American submarine, where it sounded a bit scratchier. I'm having a problem finding it, but I think this is it. The person who made the clip just layered the sound on top of his video, but I think I recognize it.
I just finished reading Steel Boats, Iron Hearts by Hans Goebeler, who was a crewmember of the U-505, the U-boat that the US captured in WWII. In it he describes being able to hear the pings, but that they had to be very quiet to do so (of course, while being pursued they were very quiet anyway, to avoid detection).
That book was great by the way, I found it a very enjoyable read (although Hans isn't exactly an unbiased source, I have no idea how well regarded it is as a history rather than a memoir).