Why does white noise work?

January 16, 2010 7:25 AM

Why does white noise work?

Background: my BF has been having a difficult time sleeping soundly and we've been advised quite a few times to try white noise. It would be used specifically to drown out other noise, but would be great if it also induced calm/relaxation. I've done some research, and have experienced white noise machines first hand (my nephew has one in his nursery and a smaller version that doubles as a stuffed animal in the car).

I ask why it works, mainly because the various sounds that came from my nephew's white noise machine (when I visited recently) sounded completely alien and almost scary to me. A couple of times it actually made me feel cold (the sound being akin to rapidly circling wind with, for whatever reason, a couple of barely audible beeps thrown in) and creeped me out to the extent of getting chills down my spine. However, it definitely worked for my nephew at drowning out noise, as we listened to music and talked loudly in the other room while the baby slept. What I don't understand is how this could possibly be the case. I wonder if it not only drowns out noise, but also helped my nephew to relax (are the two things not necessarily found in on type of white noise? Note: nephew's white noise was not swooshy water in-the-womb type sounds). I realize there are many types to choose from. I'm wondering how it works, which white noise is best for adults, and would like to hear any personal experiences people have had on the subject.

posted by marimeko to Science & Nature (20 answers total)

I've been told somewhere that adding white noise emulates the distortion of sounds that the child might have heard while in the womb. I have no idea if this is true or not, but maybe that's a place to start looking for research?
posted by ErWenn at 7:37 AM on January 16, 2010

I recommend the Marpac Sound Screen. The version I used for many years just made a whooshing noise, like a fan. It seemed to redirect my brain away from whatever noise would be keeping me awake, and helped me relax.
posted by pinky at 7:41 AM on January 16, 2010

Response by poster: I should add that nephew's nursery white noise fell somewhere wholly outside anything "human" or comforting (from my perspective). But the sounds that came from his smaller car version were mildly swooshy/gentle rainfall type sounds that I "understood".
posted by marimeko at 7:43 AM on January 16, 2010

HowStuffWorks explains it pretty well, at least so that I can understand it. It has to do with making sounds indistinguishable so that your brain doesn't feel obligated to make sense of them, and therefore can rest. Sort of the same as listening to nondescript yanni-type ambient music when getting a massage --- you don't know the tune or the words so your brain doesn't stay "on" trying to connect with it, it just becomes background and you can relax.

I don't like white noise because it keeps me from being able to hear the bad guys when they break into my house late at night.
posted by headnsouth at 7:50 AM on January 16, 2010

Masking noise can help some people sleep, as white noise covers much of the audio spectrum. For you to be disturbed by a sudden noise, it needs to be louder than the background noise. If you up the level of the background noise, most other noise becomes inaudible or less disturbing.

The sounds people find soothing can be different. Ms scruss, being midwestern, is soothed to sleep by the sound of a fan, or distant thunderstorms. Being Scottish, I'm kept awake by these unfamiliar sounds.
posted by scruss at 7:55 AM on January 16, 2010

We use a fan in our bedroom. I don't need it, but it does help mask the small/abrupt sounds in the night that might otherwise startle me awake.

scruss, thunderstorms are the best! As I get older I seem much less able to sleep continuously for long periods, but a good storm always knocks me out cold.
posted by empyrean at 8:13 AM on January 16, 2010

I think overstimulation has something to do with it. When the brain has too much information to track it compensates by shutting down and/or setting a higher threshold of noise that will get its attention. Engineers and architects design moderate levels of background noise (air conditioning, etc.) into buildings so that people aren't annoyed by small noises, like coughing and the shuffling of paper.
posted by weapons-grade pandemonium at 8:16 AM on January 16, 2010

I used to suffer from terrible insomnia. There were a number of reasons for this, but one was that I couldn't sleep unless my surroundings were perfectly dark and silent (good luck with that if you live in a large city). When I moved to Toronto a dozen years ago the rumbling of the streetcars passing my apartment drove me crazy until a friend suggested white noise (plus earplugs). It worked like a charm, and now I find it difficult to sleep if I don't have a fan running.

> Masking noise can help some people sleep, as white noise covers much of the audio spectrum. For you to be disturbed by a sudden noise, it needs to be louder than the background noise. If you up the level of the background noise, most other noise becomes inaudible or less disturbing.

This. The combination of a fan/white noise machine and earplugs (which I usually don't have to wear in my current apartment) will block out a lot of noise. Except bass. Bass will slice through anything.
posted by The Card Cheat at 8:40 AM on January 16, 2010

As far as I know white noise is relaxing only because it drowns out other sounds that might otherwise attract your attention and distract you or keep you from sleeping. I'm guessing that your nephew's white noise generator includes soft beeping sounds to make household sounds from TV's, appliances, clanking pots and pans not stand out so much. Even though it sounds weird and alien to you, your nephew will get used to to it, and it will merge into the background; other clanks and beeps from the house will blend in with the sound the machine makes and not wake him up.
posted by nangar at 10:53 AM on January 16, 2010

We play "pink" noise in both our and our daughter's room at night or during nap time. My husband is an audiophile, and insists that pink noise is superior to white noise. Something to do with the same energy output every octave vs. every frequency. He downloaded some pink noise and burned it to a CD that we play continuously. No fancy machine needed, but then you miss out on thunderstorms or oceans if that's your thing.
posted by wwartorff at 10:56 AM on January 16, 2010

white noise works for me largely because it cancels out my tinnitus, which is juuuust annoying and persistent enough that it often keeps me from fully relaxing.
posted by scody at 11:14 AM on January 16, 2010

Pink Noise is great for this purpose: it is an equal distribution of energy among octaves, as opposed to the equal distribution of energy among frequencies that makes White Noise, well, noisier-sounding. More Info Here.
posted by Aquaman at 11:16 AM on January 16, 2010

I put on simply noise when I'm on a back shift and have to sleep during the day. It's kind of irritating at first, but then kind of fades out of my attention while still masking the sounds of kids playing outside, the TV downstairs, etc.

No beepy sounds, though. I'd think that would prevent me from ignoring the cover-up noise as easily. Also I can't stand the 'oscillate volume' feature for the same reason.
posted by ctmf at 11:25 AM on January 16, 2010

We register sounds by noticing acoustic features that stand out. True white noise contains every possible audible frequency, at all times, which serves to mask the presence of any other sounds by preventing acoustic features from standing out.

A visual analog would be an overexposed picture, or snowblindness - most features are lost in the intense brightness (white light contains all visible frequencies).
posted by idiopath at 11:36 AM on January 16, 2010

Before sleeping, I run

play -n synth pinknoise

which plays pinknoise on my laptop using SoX a free, open source, cross-platform audio tool. Substitute whitenoise or brownnoise if you prefer. It's also great for doing other stuff to audio files, but that's another ask.me
posted by dirm at 11:36 AM on January 16, 2010 [1 favorite]

Try brown noise as well. Sounds almost exactly like an old TV tuned to a non-broadcasting channel.

If your white noise is producing beeping sounds, it isn't very random.
posted by gjc at 4:25 PM on January 16, 2010

Generically it's just a bland, bland noise that takes the edge off of any other noises. It shifts your "hearing" up a level - as someone said above "overstimulation" makes you less sensitive.

I'll second ctmf's recommendation of simplynoise.com - we use the Brown noise with oscillation turned on.
posted by carlh at 8:14 AM on January 18, 2010

Response by poster: Brown noise, pink noise - I had no idea! Very interesting stuff. Thanks to everyone for the input so far.
posted by marimeko at 5:33 PM on January 18, 2010

Response by poster: Also: all of the comments are favorite worthy, that's why none are highlighted..)
posted by marimeko at 5:35 PM on January 18, 2010

White noise can zone me totally out and away. In fact, it's been so long since I had that problem, I am now wondering whether my computer fan is responsible for recent sleepiness. I don't know why it does it, but I wonder if the reason the issue disappeared for awhile was due to living within hearing of the ocean for 3 years. (The brown noise, from Simplynoise, oscillated, is very much like waves on the beach).
posted by Goofyy at 9:30 AM on January 19, 2010