Dinacon 2025: Passive Acoustic Listening August 3, 2025
Whale songs were first noticed by accident, when analysts tracking Russian submarines at the height of the cold war heard cetacean interference instead. An engineer sent some recordings to Roger Payne, a biologist friend of his, who did something that proved pivotal: he played the hours-long recordings on his hi-fi at home, while he went about his day.
By listening for hours at a time, Payne noticed that these vocalizations weren’t simple chirps, but complex structured social patterns — songs, even. His 1970 album Songs of the Humpback Whale introduced the masses to these spectacular recordings and spurred a sea change in oceanic environmental stewardship.
A trendy topic in biology now is “passive acoustic monitoring,” the science of understanding ecosystems through their soundscapes. Modern machine learning is often used to analyze these long recordings and identify species, complexity and community health. But are we missing the listening?
While participating in Dinacon 2025 in Les, Bali, I investigated different techniques for collecting and listening to bioacoustic field recordings.
First, running a workshop to make inexpensive and radically accessible hydrophones that work as simply as a computer microphone.
Secondly, expanding the hydrophone to stereo. Sound propagates differently underwater, spreading farther and faster than on land, which can often turn underwater recordings into a cacophony. By using multiple hydrophones at different depths, a stereo field can be constructed that creates something spatially interpretable.
Finally, going slow with “passive acoustic listening”: a collaboration with Ashlin on new ways of listening and annotating multi-day recordings.
A $5 hydrophone construction workshop
At Dinacon 2025, I ran a hydrophone construction workshop where 7 participants were able to build a piezo-based hydrophone from a handful of electronic components. This was an evolution of a workshop I first ran at ITP Camp 2025. The full method is documented below.
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