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Most of us aren't woken by silence. We're woken by a sudden sound: a door, a dog, a truck downshifting, a partner's alarm. A white noise machine works by playing a steady sound that makes those changes less noticeable. It won't fix a sleep problem on its own, but in a noisy home it can make a real difference. We haven't lab-tested these products; this guide explains what to look for.
White, pink, and brown noise in plain terms
- White noise spreads sound evenly across all pitches. It sounds like a hiss, like TV static or an air vent.
- Pink noise turns down the high pitches. It sounds softer, like steady rain or wind through trees.
- Brown (or red) noise turns them down even more. It sounds deep and rumbly, like a waterfall or a jet cabin.
Most machines offer several of these plus nature sounds. Try a few for a week each. The right one is the one you stop hearing after a few minutes.
Give any new sound a few nights before deciding. It's normal to notice it at first; most people find it fades into the background as the brain learns it's harmless and predictable.
Fan-based vs. electronic machines
| Type | How it sounds | Good for | Trade-offs |
|---|---|---|---|
| Fan-based (mechanical) | Real moving air; natural, non-repeating | People who already sleep with a fan | Fewer sound choices; fan can wear out |
| Electronic (speaker-based) | Recorded or generated sounds; many options | Trying different noise colors and sounds | Cheap models may loop audibly or sound tinny |
| Portable / travel unit | Smaller speaker, simpler sounds | Hotels, travel, a second room | Less depth; battery or USB power |
| Phone or smart-speaker app | Depends on the speaker | Testing before you buy; travel | Notifications, screen temptation, small speakers |
What to look for
- Fine volume control, especially at the low end, so you can find a quiet setting that still covers noise.
- No audible loop. Cheaper machines may repeat a short recording, and once you hear the "seam" it's hard to ignore.
- A choice of sounds, or at least white, pink, and brown noise options.
- Continuous play. Some machines only run on a timer; most people want all-night sound.
- An optional timer, if you only want sound while falling asleep.
- Dim or no lights. A bright display defeats the purpose in a dark room.
- Power that fits your setup: wall plug for the bedroom, USB or battery for travel.
Use it at a safe volume
Louder isn't better. Long exposure to loud sound can damage hearing over time; CDC/NIOSH uses 85 decibels averaged over an eight-hour workday as its occupational exposure limit. Your sleep machine should be nowhere near that loud.
- Set it just loud enough to soften the noises that wake you, and no louder.
- Place it across the room or several feet from the bed, not on the pillow or right next to your ear.
- If you have to raise your voice to talk over it, turn it down.
Extra caution for babies
Research published in Pediatrics found that infant sleep machines can produce sound levels high enough to be a concern at maximum volume. Children's Hospital of Philadelphia advises placing a machine at least about 2 meters (roughly 7 feet) from the crib, keeping the volume low, and running it for a limited time. Never put a machine inside the crib or attached to it. Ask your pediatrician if you have questions.
When noise isn't the real problem
A sound machine helps when outside noise is waking you. It won't help much if you lie awake with a busy mind, wake at the same time every night regardless of noise, or wake up gasping. For trouble falling asleep, see what to do when you can't fall asleep. If a bed partner says you snore loudly or stop breathing, read about sleep apnea. A sleep diary can help you tell which wake-ups are noise-related.
Where to shop
Read listings for the specifics: whether sounds are looped or continuous, what the lowest volume setting is like, and whether the display can be turned off.
Browse white noise machines on Amazon
Browse fan-based sound machines on Amazon
Browse travel sound machines on Amazon
If sound is only one part of what's keeping you up, our bedroom sleep environment guide covers light, temperature, and comfort too.
Common questions
Is it OK to run a white noise machine all night?
For most adults, yes, as long as the volume is moderate and the machine isn't right next to your head. Think of a soft shower or a fan across the room, not something you have to raise your voice over.
Is pink or brown noise better than white noise for sleep?
There's no clear winner for everyone. Many people find pink and brown noise less harsh than white noise because they have less high-pitched hiss. The best choice is the sound you stop noticing.
Can I use a phone app instead of a machine?
Yes, an app works fine, especially for travel. The downsides are small phone speakers, notifications, and the temptation to check your phone in bed. A cheap dedicated machine avoids those.
Sources
- About Occupational Hearing Loss — CDC/NIOSH. www.cdc.gov/niosh/noise/about/index.html
- White Noise: Not the Right Noise — Children's Hospital of Philadelphia. www.chop.edu/news/white-noise-not-right-noise
Last reviewed and updated October 17, 2026. This article is for general education and isn't a substitute for advice from your own clinician. Read our medical disclaimer and editorial standards.
