1.   At different times rescuers detected tapping noises and followed the sounds toward trapped students.

2.   Hart says there is anecdotal evidence that elephants detect noise from such a distance.

3.   Inside the ear cups, microphones detect any noise that gets through the outer shell.

4.   Meanwhile, sonar monitors seek to detect any noise in the vicinity, listening especially for the sound of propellers.

5.   Russian surface ships soon afterward detected noises from the bottom.

6.   This is possible because of a DSP inside the phone that detects the noises and deletes them instantly.

7.   Audio equipment can detect noises as subtle as raspy breathing or weak scratching in the bowels of a toppled building.

8.   Minutes before the crash, the cockpit voice recorder detected noises, some resembling a human heartbeat.

9.   The Greeneville also had a sonar used to detect the noise of any vessel at the surface.