Bio-artist Joe Davis’ installation piece, Audio Microscope, allows not just a glimpse of the microscopic world of living cells, but a listen, too. From his write-up on the piece at Viewing Space:
At the turn of the last century Alexander Graham Bell built what was probably the world’s first optical transducer of sound waves. He called it a “photophone”. Instead of translating sound into electrical signals, Bell built an apparatus that turned sound waves into audio frequency pulses of light. He also built “detectors” that would convert audio frequency pulses of light into electrical signals that could then be converted into sound. To construct my audio microscopes I also used optical detectors and specially illuminated stages and microscope slides that allow only light reflected from the surfaces of specimens to enter the objective lens of microscopes . These optical signals are then transduced into electrical signals via detectors mounted on the microscope eyepiece. The electrical signals are subsequently routed through more or less conventional audio equipment so that they may then be perceived as sound in the ear/brain of the user/observer.
At early stages of this work I was surprised to find a wide range and diversity of information in the microacoustic world. At lab we find organisms on almost a daily basis that we have never seen or listened to before. We therefore now routinely listen to organisms for the first time. Different organisms make different sounds in the way that say, the sounds of horses are perceived as different than the sounds of sheep. My experiments with spectrum analysis tend to reinforce that notion. I found that slightly different acoustic signatures corresponded to slightly different species of microorganisms.