We Asked an Audio Engineer Which Background Noise Is Best for Concentration

There are many different background noises known to boost productivity or to help you fall asleep faster. Here’s how to find the right one for you.

When it comes to working, some of us prefer absolute silence, while others are more productive when background noise is present. Whether it’s the sounds of a coffee shop, leaves rustling, or just “noise,” technology has made it easier to tailor our preferences. No matter what environment you’re in, you can now generate a specific type of noise through an app, or simply by searching online for specific sounds. But how do you know where to start?

We’ve all heard of “white noise,” but there are actually many more types of broadband sounds, including pink, white, red, and brown noise.

The answer to why each has its own characteristics and different purpose is complex, so we asked musician and audio engineer K. Marie Kim to break it down for us. Kim has worked on tour or in studio sessions with artists like Lorde, Rosanne Cash, and Dead Kennedys. She is a monitors engineer at various music venues in New York City, and was recently touring as keyboardist for the artist Mitski.

What are the different types of broadband noises, and why are they assigned different “colors”?
Kim: There are about six defined colors of broadband noise. Pink noise and white noise are used most commonly in audio and electronic applications. I’ve also seen some references to the use of red noise (also known as Brownian noise after Robert Brown) for sleep aid or masking usage. The color name assignments are loosely correlated to colors of light. Where white light contains all visible wavelengths, red light has higher energy at lower frequency waves, and pink is the in-between.

How would you describe what you hear between the different types of broadband noise?
Kim: It helps to know that humans perceive varying frequencies as varying pitch. It’s especially easy to tell apart if you hear them closely in series. Pink noise is often heard as being even across all frequencies (it can be somewhat comparable to the fullness of a commercial pop or rock record, or perhaps closer to a dense heavy metal or noise record), mostly due to the fact that human ears are generally less sensitive to low frequencies. White noise sounds a little hissy or thin, like a small faucet running at high pressure. Red or Brownian noise on the other hand, sounds rumbly and lacks brightness, like a herd of animals moving along.

In terms of productivity, is having these types of noise better than having just silence?
Kim: There actually isn’t enough research to fully support this claim. There have been some studies that show there may be correlation between noise being present during memorization and recall tasks, but only certain people performed better with significantly loud noise compared to silence. There is the possible explanation that our brain associates the noise stimuli with memorization task functions, thus enabling more robust recall when the same stimuli are present. However, the likely explanation of why some people think they perform better with noise present is that it masks other distracting noises in our work environment. Even our quietest environment will have distracting sounds (like cute bird chirps!), and music is often an emotive and attention-sucking stimulus. So out of those options, the information-vacant stream of broadband noise can help reduce distractors to help productivity.

Are different frequencies better for different situations, i.e. sleeping or concentration, and what’s the best way to implement them?
Kim: If you have unwanted sounds you want to mask, using broadband noise on headphones can be helpful. Using pink or even red noise may prove more helpful than using white noise, since lower frequencies can mask higher frequencies, but not as much so the other way around. Broadband noise has also been shown to help you fall asleep faster by not only masking environmental sounds, but at the right volume, the randomly fluctuating nature of pink or white noise also helps increase brainwave synchronization which quickens sleep onset.

Some apps and sound machines use nature sounds. Is this as effective for concentration? Do sounds in nature have different frequencies?
Kim: Actually, a lot of these nature sound models create broadband noises. Rainfall, rustling leaves, and ocean waves are great examples of broadband nature noises that are similar to pink noise. A big difference is that white/pink/red noise are constant, randomized mathematically generated noises, while sounds in nature vary over time in power density distributions. In other words, nature sounds have audible movement over a longer time. Depending on the preference of the listener, they may find constant generated noise best for concentrating, or more natural gradually modulating noise more effective, and some may prefer layers of both kinds of noises (like me!) or a synthesized version meant to represent something in between the two worlds. Using noise to help us calm down, focus, or fall asleep quicker are easy and safe applications, but always be aware of temporary and permanent hearing damage that can occur from prolonged exposure to loud sound pressure levels.

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