It’s so quiet you can hear a pin drop on the stage of Conrad Prebys Music Center Concert Hall.
Then, the recording of a Stejneger's beaked whale plays. UC San Diego student and percussionist Camilo Zamudio is on stage, listening with his eyes closed.
He grabs two glass jars filled with marbles and starts rubbing their textured bottoms together near a microphone. They complement the sound of the whales.
In nature, humans aren’t capable of hearing these and other marine mammal sounds because they communicate with frequencies that are too low or too high for the human ear.
A new collaboration between scientists and musicians at the Laboratory for Emerging Intelligence at UC San Diego is helping make those inaudible ocean sounds perceptible to humans. It’s called “The Inaudible Ocean,” and it premieres May 20.
“We can now hear what the world sounds like at some of the most inaccessible places to human beings,” said Lei Liang, a music professor and composer at UCSD.
Liang said the process starts by gathering audio data with a microphone designed to detect and record ocean sounds.
“We work together with Whales Acoustics Lab at Scripps Institution of Oceanography and one of their great scientists, John Hildebrand, a very renowned oceanographer, what he has done is to design this microphone that records underwater, called hydrophones,” Liang said.
The hydrophones are placed at the bottom of the ocean and record year-round, he said. After researchers retrieve the instrument, they take the data to the lab and start listening.
A lot of those sound waves range from the infrasonic, or sound waves with frequencies as low as 10Hz, to the ultrasonic, sound waves as high as 320 kHz. The typical, healthy human hearing range is between 20Hz and 20kHz.
“Our brain is, compared to some of these marine mammals, quite slow and insensitive to some of the higher frequencies and extremely fast speed sound signals,” said Liang. “The only way we can actually hear them is to slow them down. Transpose them lower so that they're brought to the human hearing range.”
For example, Liang said to imagine hearing the Arctic sea ice.
“We can hear the ice formation and all that,” he said. “But when you slow down to 1% of its original speed, it becomes a totally different world because you're hearing ice formation at the microscopic level.”
These sounds also happen on timescales humans cannot perceive, said Joshua Jones, Scripps oceanographer.
“When a beaked whale makes an echolocation, it sounds like (a) click,” he said. “The animal is hearing that click and then the return of that click off all the things that it encounters in the environment. But it happens so fast, not only we can’t hear it, but we can’t even perceive that.”
Jones and Liang said they have been spending a lot of time not only observing the ocean through sound but also thinking about what music can offer to disciplines like engineering, geology and oceanography.
“Can we do something other than just play some music in a concert hall? And I think that’s behind everything that we’re trying to do here,” said Liang.
The oceanographer and composer are working with several musicians, some of whom are professors and students at UCSD, to create the immersive musical experience. Among them is pianist Cory Smythe. At a rehearsal on Monday, he played with low and high notes as different frequencies of whale sounds played.
“The Inaudible Ocean” won’t be your typical concert, Liang said.
“This is not a kind of sit in your seat and just kind of be entertained,” he said. “You’re here to rediscover some of these things that didn't exist before. They might be there, but it's only because artists and scientists are working together now that we can finally reveal the beautiful world that there is. But, it takes a community to also appreciate that.”
The premiere of The Inaudible Ocean is scheduled for 7 p.m. on May 20 at the Conrad Prebys Music Center Concert Hall in La Jolla.
