What is white noise?
Time to get a little nerdy.
Remember in science class, when the teacher shined a light through a prism to create a rainbow, showing that white light is a combination of all visible light wavelengths? Well, white noise is similar, in that it contains all audible sound frequencies.
Imagine a sound wave as ripples in water after you drop a pebble. Some ripples are close together, while others are spread farther apart. In terms of sound, when the waves are close together, the sound has a high frequency, which means it has a high pitch — like a whistle or a bird chirping. When the waves are farther apart, the sound has a low frequency, giving it a low pitch — like the throb of a bass guitar, or a deep voice.
We measure these wavelengths in hertz (Hz), which tells us how many times the sound wave vibrates per second. The higher the hertz, the higher the pitch.
White noise occurs when a sound contains all the different frequencies of sound at once, creating a consistent, even tone, and even making other environmental sounds blend into the background.
Our brains are naturally wired to pay attention to any sudden changes in our environment — like a car beeping or a door slamming — and white noise can help make these sudden noises less noticeable. This is why some people find the hum of an air conditioner or a fan particularly calming; and if you’ve ever wondered why you’re so prone to falling asleep during a long journey spent riding shotgun, you can blame the constant hum of the car’s engine!
Will white noise help my baby sleep?
White noise can help your baby sleep, but there’s no guarantee they’ll enjoy it! A 1990 study found that white noise helped 80% of newborns fall asleep within five minutes, compared to only 25% in a control group who didn’t use white noise. So, in short — yes, white noise is likely to help your baby sleep, but success isn’t guaranteed.
The pros of using white noise
One of the reasons white noise is so effective is that it mimics the sound your baby was used to in the womb. Pre-birth, your little one’s life was soundtracked by the rhythmic whooshing of blood, and white noise can replicate this environment by creating a similar soundscape.
As we touched on earlier, white noise is also brilliant at masking and disguising any sudden noises that could wake your baby up. Whether it’s barking from the dog, the clatter of dishes as you (rather clumsily) do the washing up, or a door slamming in the breeze, white noise can limit its effect on your little one’s sleep.
The cons of white noise for babies
If white noise works for your baby, there’s a chance that they could become dependent on it. This might lead to some tricky situations if you need to get your little one to sleep in a place where you’re unable to play white noise, or the device you use to create the white noise breaks.
Some white noise machines may also exceed the recommended noise limits for babies (more on that below), and just like us adults, not all babies care for white noise — you might even find that it prevents your baby from sleeping!
Is white noise safe for my baby?
Despite what you may think, white noise isn’t completely risk-free.
A study conducted by the AAP (American Academy of Pediatrics) in 2014 found that of the 14 white noise machines they tested, all of them exceeded the recommended noise limits of 50dB. Even more concerningly, they discovered that three of the machines tested were actually capable of reaching a volume above 85dB — a volume that, if played for 8 hours or more, could risk noise-induced hearing loss.
Because of this, pediatricians agree that if white noise machines are used, they should be placed at least 7 feet away from your baby’s crib or bassinet, and its volume setting never turned to max.
White noise alternatives for babies
If white noise doesn’t work for your baby, or you’re just looking for additional ways to help your baby catch a few ZZZs, try some of these calm-promoting techniques:
Swaddling
Swaddling — wrapping your baby in a thin, soft blanket — mimics the snug, safe environment of the womb, and can even reduce the startle (moro) reflex. However, it’s important to swaddle safely, following the correct technique (as detailed here), and never swaddle a baby who’s capable of rolling over, as this could lead to suffocation — you should avoid swaddling altogether by 16 weeks at the latest.
Rocking to sleep
Gentle rocking, whether in your arms or in a rocking chair, can be super soothing for your tot. A baby swing, bouncer, or smart bassinet can also provide a calming motion that helps your little one drift off, but they’re not safe for unattended sleeping.
Creating the ideal sleep environment
How snooze-ready is your little one’s sleep space? Babies love to sleep in the dark, so try to make the room as dark as possible when it’s time for bed. Blackout curtains are ideal, but shades can work wonders, too.
Next up: temperature. The ambient temperature of your baby’s bedroom needs to be just right — try to keep it between 68°F to 72°F (or 20°C to 22°C), and eliminate any cold drafts where possible.
Natural daylight
Exposing your baby to natural daylight during the day can help regulate their circadian rhythms (which begin to develop from around 6 weeks), making it easier for them to sleep at night. Try to ensure your baby gets some outdoor time or is in a well-lit room during the day.
Different ‘shades’ of noise to try
If your baby isn’t best pleased with white noise, you could always try another ‘color’ of sound. Each shade has a unique vibe, and most people tend to have a preference one way or the other. It could be the same for your tot; so if you’re curious, give these a try:
Gray noise for babies
You can think of gray noise as “white noise remastered”. With gray noise, the intensity of higher frequencies is reduced, providing a less ‘hissy’ sound, closer to a gentle hum, or the sound of wind rustling through leaves.
Pink noise for babies
Softer and more ‘natural’ sounding, pink noise is often compared to the sound of steady rain or wind. Pink noise reduces the volume of the higher frequencies and boosts the lower ends of the sound spectrum, giving it a deeper, cozier sound.
It’s often considered more soothing than white noise, and many parents find their babies prefer it — maybe because it’s one of the most commonly observed signals in biological systems. In other words, pink noise is closer to the kind of sounds your tot would’ve jammed out to in the womb!
Brown noise for babies
Brown noise (also called Brownian noise or red noise) emphasizes even more of the lower frequencies than pink noise, making it much deeper and rumbling. It resembles the low roar of thunder or a distant waterfall and is often perceived as very calming, especially for people sensitive to high-pitched sounds.
As with so many aspects of parenting, getting your baby to sleep can involve a lot of trial and error, so don’t be afraid to try the whole spectrum of sounds — you never know which (if any) your baby will prefer. Just remember to keep volume levels low (50dB or lower) and position the device at least 7 feet away from their crib!
For more tips on getting your little one off to the land of nod, check out our guide to getting your baby to sleep in a bassinet for the first time, or head to our index to view our complete back catalog of articles.
Reviewed by Rosey Davidson, Sleep Consultant, founder & CEO, in November 2024.