We make Drop, a sleep sounds app, and it is one of the options below. This page repeats published guidance and does not add medical advice of its own.
What the research found
- It can help some newborns settle. In a small randomised trial in London (Spencer et al., Archives of Disease in Childhood, 1990), 16 of 20 newborns (80%) fell asleep within five minutes with white noise, against 5 of 20 (25%) without it. The authors' conclusion is cautious: white noise “may help mothers settle difficult babies”.
- Machines can be too loud. Researchers in Toronto measured 14 infant sleep machines at maximum volume, adjusting for a 6-month-old's ear canal (Hugh et al., Pediatrics, 2014). At 30 cm all of them were above 50 dBA, the recommended noise limit for hospital nurseries, and three were above 85 dBA, which over 8 hours exceeds adult workplace limits.
- Distance and volume matter most. Writing about that study, a paediatrician at the Children's Hospital of Philadelphia advises to “place them more than 200 centimeters from the crib” and “keep the volume low” (CHOP, 6 April 2014).
- For adults the evidence is weak. A 2021 review of 38 studies rated the evidence that continuous noise improves sleep as very low quality (Riedy et al., 2021).
Safe sleep comes first
The American Academy of Pediatrics' safe sleep advice (HealthyChildren.org, updated 11 September 2026) says to place a baby on their back for every sleep, on a firm, flat surface, with “a fitted sheet only — nothing else should be in the crib”, sharing the room but not the bed for at least the first 6 months. That rules out a phone, speaker or sound machine in the cot or tied to its rails.
What we checked in Drop's code
We read Drop's sleep timer in the app's source code (SleepTimer): the options are
15, 30, 45 and 60 minutes, 2 hours, 8 hours, or no end, and in the last 30 seconds the volume falls
gradually to silence instead of cutting off. Playback is set to continue with the screen locked.
Step by step
- Choose one steady sound. White noise, a fan, rain or a heartbeat. Pick one that is even and without sudden peaks, so it does not startle.
- Put the phone or speaker far from the cot. More than 200 cm away, never in the cot or on its rails, per the guidance above.
- Start low. Set the volume at the lowest level that covers the household noise. Listen from where the baby's head is: it should sound quieter than a normal conversation.
- Set a timer. Let the sound stop after the baby is asleep unless you have decided otherwise. On iPhone, Background Sounds has Stop Sound with a Timer (Apple); apps such as Drop have their own timer.
- Use Do Not Disturb or airplane mode. So a call or notification does not play through the same speaker at full volume. Sounds already downloaded keep playing.
- Check with your paediatrician. Especially for premature babies, or if your baby has hearing or ear problems.
Ways to play it on iPhone (App Store, 23 October 2026)
- Background Sounds, built into iOS (Settings, Accessibility, Audio & Visual): Balanced, Bright and Dark Noise, Ocean, Rain and Stream, with a stop timer (Apple).
- White Noise Lite (TMSOFT): many sounds including Heartbeat and Oscillating Fan, a mix pad and a timer that fades audio out.
- White Noise Deep Sleep Sounds (Slumber Studios): 250+ sounds including Shush and Baby Shusher, sleep timer and mixing.
- Drop: 53 sounds in version 2.10 (sent to Apple on 23 October 2026), including White, Pink and Brown Noise, Gentle Breeze (a fan) and Mother's Heartbeat; 9 of them play without a subscription, White Noise and Mother's Heartbeat among them. One sound at a time (it does not mix sounds), timer from 15 minutes to 8 hours with a 30-second fade, plays with the screen locked, works offline, no account.
- Baby Sleep - White noise (AppCode): nature sounds, three kinds of white noise, a timer from 1 minute to 8 hours with a gentle fade-out.
Whichever you use, the volume and the distance are what the studies are about, not the app. More on sound colours in brown vs pink vs white noise.
Sources
- Spencer JA et al. White noise and sleep induction. Arch Dis Child 1990;65(1):135-7.
- Hugh SC et al. Infant sleep machines and hazardous sound pressure levels. Pediatrics 2014;133(4):677-81.
- Pasquariello PS. White noise: not the right noise. Children's Hospital of Philadelphia, 6 April 2014.
- American Academy of Pediatrics, How to keep your sleeping baby safe (HealthyChildren.org), read 23 October 2026.
- Riedy SM et al. Noise as a sleep aid: a systematic review. Sleep Med Rev 2021;55:101385.
- Drop source code (sleep timer and playback), App Store listings of the apps above, read 23 October 2026.
Questions people ask
Is white noise safe for babies?
The published concern is volume and distance. A 2014 Pediatrics study found 14 infant sleep machines were all above 50 dBA at 30 cm at full volume. Keep the device more than 200 cm from the cot, at low volume, and ask your paediatrician.
Does white noise help babies sleep?
In a small 1990 trial, 80% of newborns fell asleep within five minutes with white noise versus 25% without. It is one small study; it may help some babies settle.
How loud should white noise be for a baby?
Low. The 2014 study used 50 dBA, the hospital nursery limit, as the reference. In practice, quieter than normal conversation where the baby's head is.
How far should a sound machine be from the crib?
More than 200 cm, according to the Children's Hospital of Philadelphia, and never in the crib or on its rails.
Should white noise play all night?
The guidance is to keep exposure low; a timer that stops the sound after the baby falls asleep is the cautious default.
Can I use my iPhone as a white noise machine?
Yes: Background Sounds in iOS or a sleep sound app. Put the phone far from the cot, use Do Not Disturb, and set a timer.