While there’s little doubt that dolphins are saying something to one another with all their clicks, squeals and whistles, we’re still not entirely sure just what it is that they’re communicating. We may be getting closer to figuring it out, however, as Japanese scientists have created an underwater speaker that’s capable of playing back the creatures’ entire acoustic range. The next step - see how they respond.

The device was created by a team from the Tokyo University of Marine Science and Technology, working with colleagues from tech company Fusion, Inc. It can reproduce not only the dolphins’ low-frequency sub-20 kiloHertz sounds, which can likewise be made and heard by humans, but also their high-frequency sounds that we can’t hear, which go up to 150 kHz.

Tokyo University of Marine Science and Technology's "dolphin speaker"

“Acoustic studies of dolphins that have been done so far focus mainly on recordings of vocalizations and hearing abilities, but relatively few playback experiments have been conducted,” said Tokyo University grad student Yuka Mishima. “There were no speakers that could project from low to high frequencies like dolphins, although some could project the low-frequency sounds or parts of dolphin sounds.”

The speaker incorporates “new types of piezoelectric elements that had never been used for underwater acoustic transducers,” and is capable of producing sounds ranging from 7 to 170 kHz. Mishima says that they now plan on using the device to play back recorded dolphin sounds, to observe the reactions of real dolphins.

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