Swaddle
White vs pink vs brown noise
| Noise | Sounds like | Good for |
|---|---|---|
| White | Radio static, a hairdryer, a hissing fan | Masking sharp noises: a barking dog, a sibling, traffic |
| Pink | Steady rain, rustling leaves | A softer all-round sound that is easy to sleep next to |
| Brown | A waterfall, strong wind, a low rumble | Parents who find white noise harsh; masking low sounds like footsteps |
The "colors" describe how the sound's energy is spread across pitches. White noise is equal across all of them, which our ears hear as bright. Pink noise drops by half with every octave up, and brown noise drops even faster, so each one sounds deeper than the last.
Does white noise help babies sleep?
There is some evidence it helps babies fall asleep. In a small, often-cited 1990 study, 16 of 20 newborns fell asleep within 5 minutes with white noise, compared with 5 of 20 without it. Research on noise and sleep in general is mixed and mostly small, so it is fair to call white noise a low-risk helper rather than a cure.
What it does reliably is mask other sounds. A steady background sound makes a door closing or a dog barking less likely to wake a light sleeper, especially at the end of a sleep cycle.
There is no research comparing brown, pink and white noise for babies. Pink noise gets attention because of studies in adults, where gentle pink-noise sounds played at specific moments of deep sleep seemed to boost it. That has not been shown in babies, and it is a different thing from playing steady pink noise all night.
How loud is safe?
The 3 rules: keep the sound source at least 7 feet (about 2 meters) from the crib, use the lowest volume that works, and do not put a speaker inside the crib or bassinet.
In 2014, researchers measured 14 infant sleep machines. At full volume and close to the crib, all of them went above 50 decibels, the level once recommended as a limit in hospital nurseries, and some were loud enough to be a concern for hearing with long exposure. The authors advised placing machines as far from the crib as possible, keeping the volume low, and not running them for long periods at high volume.
A phone's volume cannot tell you the decibels in your baby's room. If you want to check, a free sound meter app held where your baby's head lies gives a rough reading. Aim for under 50 dB, about as loud as a quiet conversation.
Tips for using noise at night
- Start the sound as part of the bedtime routine, so it becomes a sleep cue.
- Use the same sound for naps and nights.
- Choose a steady sound over music or songs that change and loop.
- If you play it all night, keep it quieter rather than louder.
- To stop using it later, turn it down a little every few nights.