Maybe a friend swears by hers, or you read a headline saying sound machines can harm hearing. Now you are standing in the nursery wondering whether that little box is helping or hurting. Using a sound machine for baby sleep is a common choice, and it fits alongside the basics in our guide to safe sleep practices.
The good news: the research does not say “never.” It says “how.” Distance, volume and how long the machine runs make most of the difference. You can find more answers like this on our baby sleep page.
Quick answer: is a sound machine good or bad for babies?
A sound machine is not bad in itself, but it can be too loud. A study in the AAP journal Pediatrics found some machines at maximum volume reach levels that may harm infant hearing. The researchers advise placing it as far from your baby as possible, keeping the volume as low as possible and limiting how long it runs.
- Keep it out of the crib and off the crib rail.
- Use the lowest volume that works, never the maximum.
- Use a timer, or turn it off once your baby is asleep.
What the research says
The best-known study, published in Pediatrics in 2014, tested 14 infant sleep machines at full volume. Researchers measured the sound at crib-rail distance (about 1 foot), beside the crib (about 3 feet) and across the room (about 6.5 feet). Every machine was louder than 50 dBA at the two closer distances. That is the level recommended for babies in hospital nurseries. Three machines went above 85 dBA, a level that, over 8 hours, is above the noise limits set for adults at work.
Two things are worth knowing. First, the study measured maximum volume, not how parents actually use these machines, and it did not test any baby’s hearing. Second, sound dropped as distance grew, and most machines had a volume control. The authors concluded that safer use is possible.
The National Institute on Deafness and Other Communication Disorders (NIDCD) explains that sounds at or below 70 dBA are unlikely to cause hearing loss, even after long exposure. Long or repeated exposure at or above 85 dBA can cause hearing loss. A 2024 review of the research found that loud, continuous white noise may affect hearing and development when devices are used incorrectly, while low-intensity sound may be beneficial during sleep. The reviewers called for limits on maximum volume and duration, and more research.
How to use a sound machine more safely
| What | What to do | Why |
|---|---|---|
| Placement | Never in the crib or on the crib rail | The AAP advises nothing in the crib but a fitted sheet; the crib rail is also where sound is loudest |
| Distance | As far from your baby as the room allows | Sound drops with distance; the researchers suggest more than 6.5 feet (200 cm) may help, though they did not set a “safe” distance |
| Volume | As low as works, never the maximum | Many machines go well above 50 dBA at full volume |
| Duration | Use a timer or switch it off once your baby is asleep | Hearing risk depends on both loudness and time |
| Cords | Keep the machine and its cord at least 3 feet (about 1 m) from the crib | The CPSC advises this distance for monitors and cords to lower the risk of strangulation |
A sound machine is just one part of the room. For temperature, light and what belongs in the crib, see our guide to the best sleep environment for babies.
If you use sound as a sleep cue, try switching it on as the last step of a calm, predictable routine, then letting the timer end it. Our bedtime routine guide walks through the other steps.
Related: Yogasleep Dohm review: how loud it gets in a nursery.
When to talk to your doctor
The CDC says signs of hearing loss are worth watching for, even if your baby passed a hearing screening before. Talk to your pediatrician and ask about a hearing check if your baby:
- does not startle at loud noises
- does not turn toward the source of a sound after 6 months of age
- seems to hear some sounds but not others
- turns when they see you, but not when you only call their name
- does not say single words such as “mama” or “dada” by 1 year
You can also bring up sound machine use at a regular checkup if you are unsure about your setup.
Frequently asked questions
Should a sound machine run all night?
The Pediatrics researchers suggest limiting how long it runs, for example with a timed shut-off or by turning it off after your baby falls asleep. If you do keep it on longer, keeping it far away and at a low volume matters even more.
Can I attach a sound machine to the crib?
For sleep, keep it out of the crib and off the rail. The AAP advises that nothing but a fitted sheet should be in the crib, and crib-rail placement gave the loudest readings in the study.
Does my baby need a sound machine?
No. A sound machine is optional and is not part of the AAP’s safe sleep recommendations. Some families like how it masks household noise; others never use one. Either choice is fine as long as the safe sleep basics are in place.
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Sources
- American Academy of Pediatrics, Pediatrics: Infant Sleep Machines and Hazardous Sound Pressure Levels (Hugh et al., 2014)
- HealthyChildren.org (AAP): How to Keep Your Sleeping Baby Safe: AAP Policy Explained
- NIDCD (NIH): Noise-Induced Hearing Loss
- CDC: About Hearing Loss in Children
- U.S. Consumer Product Safety Commission: Top Tips: Safer Spaces for Baby
- PubMed (NIH): Continuous white noise exposure during sleep and childhood development: a scoping review (De Jong et al., Sleep Medicine, 2024)
This guide is general information, not medical advice. If you are worried about your baby, talk to your pediatrician.