Where to Put a Sound Machine in the Nursery

Short answer: put it across the room, ideally 6½ to 7 feet or more from the crib. Put it between your baby and the noise you're trying to cover, like the door or hallway. Never place it in the crib or on the rail, and keep its cord at least 3 feet from any part of the crib.

Rule 1: Never in or on the crib

The crib should hold your baby and nothing else. The American Academy of Pediatrics recommends a firm, flat sleep surface kept free of soft objects and loose bedding. [1] A sound machine attached to the rail or tucked into the corner adds clutter and a cord, and it puts the speaker inches from your baby's ears.

Researchers who tested infant sleep machines specifically advised parents never to place them in the crib or on the crib rail. [2]

Rule 2: Distance turns the volume down for you

In a 2014 study, 14 infant sleep machines were measured at full volume at 30 cm, 100 cm and 200 cm. Every one exceeded the 50 dBA hospital nursery benchmark at 30 cm, about crib-rail distance. [3] The study's authors encouraged parents to place machines farther than 200 cm (about 6½ feet) from the infant and to lower the volume. [4]

Every doubling of distance cuts the sound level. It drops about 6 dB per doubling in open space, and somewhat less in a furnished room. [5] Moving a machine from 1 foot to 7 feet away can lower the level at your baby's ear by roughly 10 dB or more.

Rule 3: Put it where the noise comes in

A sound machine works by masking: steady sound makes sudden noises less noticeable. Masking works best when the machine sits between the noise and your baby.

• Noisy hallway or siblings? Place it near the nursery door.
• Street noise? Place it near the window, away from the crib.
• Dog barking in the next room? Place it on the wall you share with that room.

This also lets you use less volume, because the machine is close to the noise instead of close to your baby.

Rule 4: Cords stay out of reach, 3 feet minimum

The U.S. Consumer Product Safety Commission (CPSC) warns that baby monitor cords have strangled infants and toddlers. In one safety alert, it reported seven deaths since 2002, in children between 6 and 20 months old. [6] The same rule applies to any corded device near a sleep space:

• Keep cords at least 3 feet from any part of the crib, bassinet or play yard. [6]
• Check wall-mounted devices too. Hanging cords can be reachable. [6]
• Re-check as your baby learns to roll, sit, stand and reach.

Rule 5: Make it stable and out of reach

• Put it on a dresser or shelf where it can't fall or be pulled.
• Don't hide it under blankets or pillows. That can trap heat and muffle the sound unevenly.
• If your baby can reach it from a changing table or play area, move it.

A quick nursery checklist

• Machine is 6½ to 7 feet or more from the crib.
• Nothing is in or on the crib except your baby.
• The cord is 3+ feet from every part of the crib.
• The machine sits between the crib and the main noise source.
• The level at the mattress reads 50 dBA or less.

Frequently asked questions

Can I put the sound machine under the crib? No. That keeps it close to your baby and puts a cord near the sleep space. Place it across the room.

What if my nursery is small? Use the farthest spot you can, lower the volume, and measure at the mattress. Distance helps, but the reading at your baby's head is what counts.

Does the machine need to face the crib? Not necessarily. Pointing it toward the door or the noise source often masks better at lower volume.

How the ARC is designed to help

The Selah ARC System, now in development, is built around this placement. The speaker goes wherever noise enters the room, and a separate sensor at the crib measures what actually reaches your baby, so you don't have to guess. Follow the build.

This article is general information, not medical or safety advice. Always follow your products' instructions and your pediatrician's guidance.

Sources

1. Moon RY, Carlin RF, Hand I; Task Force on Sudden Infant Death Syndrome and Committee on Fetus and Newborn. Sleep-related infant deaths: updated 2022 recommendations for reducing infant deaths in the sleep environment. Pediatrics. 2022;150(1):e2022057990.
2. NEJM Journal Watch. Sleep machines may damage infant hearing (summary of Hugh et al., 2014).
3. Hugh SC, et al. Infant sleep machines and hazardous sound pressure levels. Pediatrics. 2014;133(4):677–681.
4. American Academy of Pediatrics. News release on infant sleep machines, March 3, 2014, as republished by eNews Park Forest.
5. HyperPhysics, Georgia State University. Measured sound in a room.
6. U.S. Consumer Product Safety Commission. Baby monitor cord safety alert.