White noise might sound high-tech, but it’s actually inspired by your baby’s experience in the womb. Before arriving in the world, they enjoyed a constant, comforting soundtrack of blood flow and heartbeats. But comforting doesn’t mean quiet. In utero noises have been recorded as reaching up to 91 decibels. For comparison, a vacuum cleaner is around 70 to 80 decibels and a hairdryer around 85 decibels. 

Broadly, white noise refers to sounds that mask other sounds, like traffic in a city. And for parents struggling to get their newborn to fall asleep (or stay asleep for any length of time), it can be a winner. Gadgets and apps like Moshi use white noise to create a calming, womb-like environment for little ones. 

The benefits of white noise are backed up by research. One groundbreaking study, published in the Archives of Disease in Childhood in 1990, examined 40 newborns and found that 80 percent of them were able to fall asleep after five minutes of hearing white noise. And it’s not only white noise that can help encourage your baby to sleep.

Here’s the rundown on your color noise options, and how to use them.

What is white noise?

This noise creates a constant ambient sound, a bit like a radio tuned to an unused frequency. It’s called “white” noise because, like the white light that is a combination of all the different colors of light, it is made up of all the different frequencies of sound. When low, medium, and high-frequency sounds are played together at the same intensity, this effectively masks other sounds that might prevent or disturb sleep, like a door slamming or people talking. 

A wide range of white noise machines are available, some of which are designed to use with babies. They often include instrumental lullabies or “whooshing” heartbeat noises designed to mimic the environment of the womb. If your baby tends to fall asleep at noisy times, they might respond well to white noise at nap time and bedtime.

What is Pink Noise?  

Pink noise is basically white noise but with reduced higher frequencies. It might be more beneficial for older babies (four months plus), too. This is because infant development ramps up around this stage, which can come with sleep regression. Pink noise is believed to be more soothing than white noise. Research suggests that it may help babies fall into a deeper, longer sleep. 

In one study, published in Neuron in 2013, researchers synced pink noise with participants’ brainwaves, so that it played when their brain activity registered deep sleep. Compared with no noise, the pink noise corresponded with a longer duration of deep sleep. However, it’s important to note that this was a study of adults, not babies.

Remember, Safety is Key 

A study from researchers at Toronto’s Hospital for Sick Children, published in Pediatrics in 2014, found that many white noise machines reach unsafe levels of up to 85 decibels. The same year, the American Academy of Pediatrics warned that a white noise machine over 50 decibels (the recommended noise limit for infants in hospital nurseries) could cause damage to a baby’s hearing as well as auditory developmental delays. 

But that doesn’t mean you have to rule out a noise machine if you think it might help your baby sleep. Just make sure you do your research on the machine you’re thinking of buying, and take all recommended safety precautions. 

The Pediatrics researchers offer a few tips; position the machine as far away from your baby’s bed as possible and keep the volume at 50 decibels.

Some experts believe that pink noise is safer because it’s at the lower-frequency end of the spectrum. Since the human ear is less sensitive to low-frequency sounds, they’re less likely to damage your hearing. 

Noise machines come in all shapes and sizes, including battery-operated models, and those that only work on a timer. Bear in mind that your baby may wake when the machine stops making noise, which makes a machine that can run all night an attractive option. 

Moshi includes several tracks with white and pink noise — perfect for recreating calming womb-like environments. Check out Flumpy’s White Noise Machine (now available on YouTube) and Moshi Pink Noise, both free in the Moshi app.

Alyssa Morgan