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Humans have some ability to localize sound based on the fact that a sound strikes one ear a fraction of a millisecond sooner than it strikes the other ear. Our brain calculates a location based on this time delay.
But sound travels about 4.5 times faster underwater than in air. So the time delay between the two ears is only about 22 percent of what our brains expect. So underwater, every sound seems to come from directly in front or overhead or behind.
Imagine that a scuba diver's ears were each plugged by headphones that blocked all sound, but recorded the sounds, compared the sounds with each other, determined the time delay between the two ears, then replayed the sounds with 4.5 times the time delay. Then theoretically, we should be able to more accurately localize sound underwater. A low tech alternative would be for each ear to be plugged with a trumpet-like device a foot long or so, or each ear connected to a microphone such that the microphones are separated by 4.5 times the distance between the ears. |
