Thousands of miles away, underwater microphones all over the Pacific are to pick up the faint signals.

Instead, larger boats and planes or underwater microphones will scan the waters for signs of animal distress.

He said the device, a sort of "underwater microphone," was expected to arrive on Long Island sometime today.

Transducers were a type of underwater microphone.

The sounds, which are inaudible to people under water, were detected by linking a highly sensitive underwater microphone to a miniature video camera.

Chow was amazed as he listened to Tom gliding about, via an underwater microphone.

Loud sounds of low frequency produced in this channel have been detected by hydrophones (underwater microphones) halfway around the world.

Unfortunately, since we'd only just thought of it, we didn't have an underwater microphone with us.

They used high-performance optical instruments and underwater microphones in an attempt to locate one of the dolphins.

Suddenly, one afternoon, the cracking stopped and he began receiving a tapping sound, as if something was rapping a pencil on the underwater microphone.