underwater sounds heard at three sites in the indian ocean, two of them very close together. the question now, were they from the flight's missing pinger? a chinese ship detected pulse signals on consecutive ships. an australian ship is also investigating pings it detected from the north. so let's try this again. wave been talking about this. we'll get to the pulse and all those things. you were saying once we do get those things, if we do get them, you said we can distinguish whether the pilot or the co-pilot or who was talking. something very interesting you said, we don't need to hear them talking. even just from listening to the airplane sounds, the am beent noises, you can tell what's going on? >> we can track the engine sounds, any of the alert sounds.