A Rainbow of Noise - a podcast by PRX

Everybody knows about white noise — that sound that comes out of your TV when it’s not working quite right. But there are many other colors of noise, too: pink, brown, blue, and purple. Marnie Chesterton brings us this story on the colorful science of sound.

Play with your own noisy rainbow — and learn more about each color — by clicking here:

Inside the Episode:

We meet Shelley, who uses pink noise to drown out the constant ringing in her head (tinnitus); Professor Trevor Cox at the Acoustic Engineering group at Salford explains why engineers need to classify different frequencies this way; and Cyrus Shahrad, electronic music producer, whose love of brown noise filters through into his work.

Producer/reporter Marnie Chesterton

We asked Marnie how she got interested in making a story about the science of sound.

She tells us that she came across this story idea after having heard about pink noise. She began an investigation sparked by her own curiosity about the spectrum of sound: “I started unpicking the stories of different colours of sound, mainly by talking about this topic to everyone I could think of,” she recounts. “After a few chats with various academics, I came to Professor Trevor Cox, an acoustic engineer at Salford University, who is obsessed with qualities of sound – reverb, echo.”

Prof. Trevor Cox

Through Trevor Cox, Chesterson got a first-hand look at an anechoic chamber, a whole room constructed to deaden any type of sound whatsoever. She describes the room as the most bizarre one she’s been in for a while: “The walls and ceiling are covered with these meter-long, dark grey foam spikes, and the floor, if you can call it that, is a mesh a bit like that of a trampoline. Through the holes in the floor, I could see down into darkness, maybe more foam spikes.”

Imagine a room that is so silent that the sounds seem to come from your own head. Chesterson explains, “The brain’s response to that kind of silence is to fill it with something, anything. And that’s what tinnitus is.”

If you’re interested in exploring the different bands of sound described in Chesterson’s story, you can play with the companion interactive rainbow of noise. Listen to which bands are used to treat tinnitus, to describe regime shifts in climate, to help sirens cut through background noise, and more.

A Rainbow of Noise was produced by Marnie Chesterton and mixed by Henry Hocking. It was hosted for this episode of Transistor by Genevieve Sponsler and mixed by Erika Lantz.

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