The Difference Between White Noise, Pink Noise and Brown Noise
Updated: Feb 21
In the parenting circles, the use of “white noise” as a baby sleep sound has become nearly as trendy as the Baby Bjorn and the Lulu Lamb and Blankie. But what is it, exactly? Well, the technical definition of white noise is, “a random signal with a constant power and spectral density.” :-/ (Yes, that makes almost no sense to me either.)
Loosely translated, think of it as all the audible frequencies of sound projecting at equal strength… kind of like how white light is a combination of all the colors of light. (Again, that is a loose translation… I don’t want to get the science people up in arms over me dumbing things down.)
In the white noise for babies world, the term “white noise,” has become something we use when talking about most any sort of steady, consistent sound. White noise peddlers (yes, such as myself) put sounds like Vacuum Sounds, Fan Sounds, Shower Sounds, etc. all under the white noise umbrella, even though technically they aren’t white noise. The closest sound to white noise out in the real world is the sound of static…. that lovely analogue sound the TV makes on a channel that has no station… yep, that’s it.
So how come that horrible, anything but pleasant sound has become so trendy? For starters, it’s creates an excellent masking effect. It blocks out unwanted sound and creates an overall “wall of sound”, so noises and changes in sound around us are less perceptible to light sleepers.
Additionally, babies actually like noise (See my prior post, “Turn on the Noise, The Baby is Sleeping”). The womb is a very noisy place, and sound white noise produces calms babies, and brings them back to that familiar environment.
So, getting back to the original point of this article… what is the difference between white noise and pink & Brown noise? Lets start with pink noise. Essentially, pink noise is white noise, but slightly lower sounding. Whereas white noise has all the frequencies of sound playing at equal strength, pink noise has more power going to the lower frequencies, and less to the higher. Pink noise still sounds like static, but not as harsh and high pitched as white noise. There is actually a very specific mathematical formula for how you would achieve producing pink noise.
Brown noise takes that same concept that’s applied to pink noise one step further. It has even less power going to those higher frequencies, thus producing and even lower tone, and some might say and even more pleasant tone, than white and pink noise. The low roar produced by Brown noise has a similar sound quality to a raging river, or the roar of the ocean.
And here’s a little fun fact you can use to dazzle your friends at dinner parties… in addition to white and pink noise, there are other sounds associated with the color spectrum, such as violet noise and grey noise, that each have their own unique sounds. The name, Brown noise, however, wasn’t derived from the color spectrum, but from Brownian motion. And Brownian motion was discovered by Robert Brown. Mind blown.
As you have notice sprinkled throughout this article, for your listening pleasure, I have have provided you with a sample of white, pink and Brown noise so you can hear the difference for yourself.
These sounds can also be found in our Baby Sleep Sound section of our website. And if there’s a certain quality to the Brown noise you like, but it’s not quite natural enough for you, you can find sounds like Rushing River and Ocean Roar in our Nature Sleep Sounds section.
If you have any questions about white noise or sleep sounds, send us a note via the form at the bottom of the page, and I’ll do my best to answer it for you.