New Underwater Microphone Inspired By the Design of Orca Whale’s Ear

Stanford University researchers say they have developed an underwater microphone, using technology inspired in part by the ears of an orca whale, that is capable of capturing sound frequencies across a span of 17 octaves even at high-pressure depths. While existing underwater microphones typically have limited range because of the variations in background pressure that become increasingly intense at greater depths, the Stanford team found that allowing water into the microphone maintains equal pressure on each side of the membrane, regardless of depth. Their ultimate design uses a pea-sized instrument that is able to damp the extent to which its membrane moves in response to any sound wave that strikes it. Noting the connection to orcas, Onur Kilic, a Stanford researcher and lead author of the study published in the Journal of the Acoustic Society of America, said, “Orcas had millions of years to optimize their sonar and it shows. They can sense sounds over a tremendous range of frequencies and that was what we wanted to do.” The microphone, which actually contains three separate sensors “tuned” to different volume ranges, can capture a range of 160 decibels. Ultimately, researchers say, the technology could be used for a wide range of research, from surveying the ocean floor to monitoring ultra-high-energy neutrinos.