Glossary
White noise
A steady, unchanging sound used to mask household noise and support more consistent naps and nighttime sleep.
White noise is a steady, consistent sound, sometimes literally white noise and sometimes a fan, rain or static-style sound, played to mask sudden household noises like a door closing or a sibling talking down the hall. The goal is consistency, a sound that does not itself have peaks and dips that could startle a light sleeper.
Machines vary from simple single-sound devices to app-connected speakers with dozens of sound options and scheduling. Placement and volume both matter, most guidance suggests keeping the machine across the room rather than inside or attached to the crib, and at a moderate volume rather than turned up to fully drown out every noise in the house.
A common mistake is running white noise at a high volume continuously for convenience, or placing the machine directly next to the crib rail where the baby's head ends up close to the speaker. Another is relying on a phone app with the volume turned all the way up as a substitute for a dedicated machine with a capped output level. Lower, farther away, and consistent works better than loud and close.