The Full Spectrum Of Colored Noise

You probably already know about white noise—the kind that sounds like a whirring fan or the static emanating from a radio—and maybe even use it to sleep. But recently, social media posts have drawn attention to its siblings: brown noise, pink noise, and green noise.

Of course, you can’t see sound, so you might be wondering what exactly these colors mean. Essentially, each one emphasizes a different frequency, which means they all sound different, says Noah Rosen, MD, a neurologist at Northwell Health Physician Partners Neuroscience Institute at Great Neck.

People want to find out what these colors actually represent—and figure out how they affect the brainwaves, although that research is still emerging. Here’s a look at how the most popular color sounds differ from each other, and how each one can be utilized.

Historically, white noise is the only colored noise that’s been a household name. “It has a long history, hundreds of years at least, for its use for sleep,” Rosen says. White noise includes all the frequencies of sound available to the human ear, and its energy is equal across those different bands. (Its name is a nod to white light, which combines all the colors that exist in the visual spectrum.) As the authors of one study put it: “If all the sounds an individual can hear are combined, we will have white noise.”

Research suggests white noise improves sleep quality and duration. In one study, listening to it reduced the amount of time it took participants to fall asleep by 38%. It can be especially helpful in high-noise environments since it helps block out distracting sounds. Some studies have found that white noise may also help people with ADHD focus better on tasks that require paying close attention.

In addition, white noise can help relieve ringing in the ears, otherwise known as tinnitus. “When it gets quiet, tinnitus symptoms often get worse,” Rosen says. “So, a lot of people will use those white noise devices to reduce that exacerbation.”

Brown noise is softer than white noise. While it combines all the different frequencies, “it’s a steeper drop-off of the highest sounds—they actually compare it to rumbling thunder,” Rosen says.

Other examples of brown noise include ocean waves and waterfalls. Sound soothing? It’s supposed to be. Researchers don’t know a lot about brown noise yet, but one study found that workers in an open-plan office were better able to focus on their tasks while listening to brown noise via headphones. So, if you’re just sitting down to tackle a big project, it’s worth testing out whether brown noise helps your productivity.

Pink noise is like white noise, but with more pronounced lower frequencies. “It seems to blunt some of those higher-end octaves,” Rosen says, so it’s not as harsh to the ear as white noise can be. Think a gentle rainfall, the wind, or leaves lightly rustling on a pleasant day.

Some research suggests that pink noise promotes the slow brainwaves associated with deep sleep while decreasing complex brainwaves. So, if you listen to pink noise overnight, you might find that you have fewer sleep disruptions and be able to enjoy a deeper, longer slumber.

While research is still in the early stages, another study found potential cognitive benefits. After listening to pink noise, older adults performed better on a memory recall test the next day than those who didn’t listen. However, the research was small, so more work is necessary to reach any conclusions.

 “Pink noise and brown noise drop off the high end, but green noise tries to drop off both high and low,” says Rosen. “It really focuses more toward sounds on the middle of the spectrum, like the human voice.”

While some people on social media report that green noise helps them sleep better, there’s no research yet on the health benefits associated with it.

Researchers still don’t know a lot about colored noise, Rosen emphasizes. “The popular use of these has probably far outstripped the evidence or research behind some of it,” he says. “That drives us to want to learn more about what might be helpful, where it might be helpful, and if there are safety concerns around any of these.”

And colored noise might not be right for everyone. Rosen specializes in headache disorders, and part of the condition can be noise sensitivity, which means many of his patients prefer silence. In addition, some people have misophonia, which is when someone finds certain sounds unbearable.

But if you’re interested in giving it a whirl, Rosen suggests experimenting with all the different colors to figure out which you like best. The different frequencies will stimulate everyone’s brain differently, so you might be drawn to pink noise while your spouse prefers brown. While white noise machines are readily available for sale, you may need to turn to YouTube videos for some of the newer sounds.

Rosen recommends playing color noise at the minimum effective volume. “Try not to turn it up too much,” he says. If it gets too loud, you could damage your hearing. It’s also a smart idea to set a timer for about an hour, perhaps right before you go to bed, rather than having the noise play on a loop all night so you don’t become dependent on the noise to sleep.

And stay tuned for more research in the coming years. “There’s probably more scientific research around the use of different color light therapies,” Rosen says. “I would hope that this area sees similar growth.”

• Could white noise help you sleep soundly?
• Find out if you should embrace essential oils.
• Read up on Northwell’s Sleep Disorders Center.