The visual environment of a nursery gets all the planning attention. The colour of the walls, the curtains, the pattern of the cot bedding. The acoustic environment — what the room actually sounds like — usually gets none. And the acoustic environment is, by some margin, the more developmentally consequential one.
A baby spends their day moving between rooms with quite different sound properties: the bright stimulating kitchen, the soft quiet bedroom, the family living room with the television on, the bathroom with its tile and echo. Each of these has implications for how the baby's developing auditory system processes information, how easily they settle, and how well they sleep. Some sound is good. Too much is overstimulating. The wrong kind in the wrong room can undermine the rest of what you are doing.
Healthbooq brings together evidence-based guidance on the early sound environment, including how a curated lullaby and visualisation library like Muna's fits into a thoughtfully designed acoustic space.
Why Decibels Matter, and How to Measure Them Accurately Enough
Decibels (dB) are a logarithmic measure of sound intensity. A 10 dB increase corresponds to a tenfold increase in sound power and is perceived as roughly twice as loud. The numbers most parents need to hold:
30 dB — a quiet bedroom at night, a soft whisper.
40 dB — a quiet office, a refrigerator hum.
50 dB — moderate rainfall, normal conversation at a distance.
60 dB — close conversation, a typical television at moderate volume.
70 dB — a vacuum cleaner, busy traffic from inside a car.
80 dB — a hairdryer at close range, a noisy restaurant. Above 80 dB, sustained exposure begins to cause hearing damage in adults.
For infants the safety margins are tighter. The American Academy of Pediatrics and most national paediatric bodies recommend that sleep-environment continuous sound stay below 50 dB measured at the baby's head, and that any sound machine or audio device kept in the room not be capable of exceeding about 50–60 dB at the distance it is placed.
You can measure this yourself. Decibel-meter apps for smartphones — both Apple and Android — have been validated in several peer-reviewed studies (Kardous and Shaw, NIOSH, 2014 and 2016) as accurate to within 2–3 dB compared to professional sound level meters, particularly in the speech-frequency range that matters for infant exposure. Free apps such as NIOSH SLM (iOS) or Sound Meter (Android) are sufficient. Hold the phone at the position the baby's head will be — in the cot, on the changing table, on the play mat — and watch the reading for thirty seconds.
If your sleep room measures above 50 dB during quiet activity, the source is worth identifying. Common culprits: an air purifier or humidifier at the wrong setting, a sound machine on too high, traffic noise through a thin window, a heating vent.
The Sleep Room: Quiet, Stable, and Sometimes Empty
The sleep room has the strictest acoustic requirements of any space in the house. The goal is a stable, low-volume environment that supports the descent into sleep and does not produce sudden disturbances.
Continuous sound levels: under 50 dB at the cot. This includes any white noise machine, lullaby app, or humidifier running in the background. A common error is setting a sound machine "loud enough that I can hear it from the next room" — at that volume it is almost certainly above 60 dB at the cot, which is louder than is appropriate for sleep and louder than the level shown to be safe for prolonged exposure.
The 2014 JAMA Pediatrics study by Hugh and colleagues tested 14 commercially available infant sound machines at the volumes and distances parents typically used them. Three of the fourteen produced sounds louder than 85 dB at 30 cm — louder than industrial noise standards consider safe for adult workers — and most produced over 50 dB at 1 metre even at moderate settings. The recommendation that emerged from that paper was: place sound machines as far from the cot as practical, use them at the lowest effective volume, and limit duration where possible.
Music for sleep: under 50 dB, instrumental or vocal lullabies, slow tempo (60–80 bpm), no sudden dynamic changes. A curated lullaby app — Muna, for example — has the advantage that the curation is already done; the recordings are pre-selected to fit these parameters, which generic streaming playlists are not. The kaleidoscope visualisations in apps of this kind are screen content for the parent during settling, not for the infant — the cot itself should be free of light sources.
When silence is better than music: if the baby has fallen asleep in silence, do not add music for the rest of the night. The change in auditory environment becomes a sleep-association problem (see the article on music and sleep). For night sleep, decide before bedtime: either continuous music throughout the night on a loop, or silence after the baby is asleep. The mistake is music that runs for thirty minutes and stops.
For parents who use white noise: continuous low-volume white or pink noise (under 50 dB) is well-tolerated by most infants and can mask intermittent household noise that would otherwise wake them. Pink noise, which has more low-frequency energy than white noise, is generally easier on adult ears in the same room and many infants seem to settle to it slightly faster than to white noise, though the evidence comparing them is thin.
The Play Space: Variable, Engaged, Not Overstimulating
The play space — the living room mat, a corner of the lounge, a designated play room if you have the space — has different acoustic goals. Here you want some variation, some content, and active engagement, but without crossing into overstimulation.
Reasonable continuous levels: 40–65 dB during active play. A normal conversation between adults sits at around 55–60 dB; a television on at moderate volume is around 60 dB. Playing music at 50–60 dB while a baby plays on the floor is fine and arguably useful — it provides a richer auditory environment than silence and is part of how babies build broader rhythmic and melodic awareness.
What to avoid in the play space: a constant loud television in the background. The American Academy of Pediatrics has documented that secondary television exposure (the TV is on but the baby is not watching) is associated with reduced parent-infant verbal interaction, and the volume levels of background TV often push above the level where it begins to interfere with how clearly the baby hears their parents' speech. If you watch TV, watch it deliberately and turn it off when you are not.
Music in the play space: this is where you can use a wider range than the sleep room — varied tempos, vocal music, even music at moderate energy. The play space is also where the kaleidoscope content of an app like Muna becomes useful for shared interaction: holding a baby up to watch the slowly evolving patterns while a piece of music plays gives a multisensory shared focus that supports both attention and parent-infant joint engagement.
Toy noise: this is where decibel meters surprise people. Many battery-operated infant toys — the ones that sing, beep, talk, and play tunes — measure 70–90 dB at close range. A toy held 20 cm from the baby's ear (which is where infant toys often are) produces an exposure level that would not be acceptable in any adult workplace. The 2018 Sight and Hearing Association noisy toys list and the older PIRG reports both flag this issue. The solution is straightforward: tape over a portion of the toy speaker, or remove the batteries, or simply choose toys that do not produce electronic noise. The baby is not missing anything developmentally if a toy does not sing.
The Feeding Zone: Calm, Low, Stable
Feeding — whether breastfeeding, bottle feeding, or weaning meals — benefits from the calmest acoustic environment of the day. Babies who feed in a quiet, low-stimulation environment generally feed more efficiently and disengage less, particularly in the first months when feeding requires significant concentration.
Reasonable levels: under 50 dB during feeds. This means turning off the television, putting the phone face-down on silent, and not running the dishwasher or vacuum during the feed if you can avoid it. A small amount of soft instrumental music (under 45 dB) is fine; busy music or talk radio is counterproductive.
For parents who like to listen to music or a podcast while feeding (which can be a significant part of how a parent stays sane during the long feeding hours of the early months): use one earbud at moderate volume, or a Bluetooth speaker placed across the room rather than next to the baby's head. Both keep the baby's exposure low while preserving the parent's quality of life.
The Bath and Changing Areas
Bathrooms are acoustically harsh: tile and water create echo and amplify sudden sounds. Hair dryers, taps, and bath toys that squeak or play tunes can produce sharp peaks well above 70 dB.
If your baby finds bath time stressful, the acoustic environment may be part of the reason. Practical adjustments: a soft mat on the bathroom floor near the bath dampens the echo somewhat; speaking and singing softly at close range is more reassuring than the same voice at distance in an echoey room; and avoiding electronic bath toys preserves the calm.
The changing area benefits from a quiet, predictable acoustic. This is a useful place for a single, repeated song — the same nappy-change song every time — which provides a brief, familiar musical signature for a routine moment. A song repeated in the same place at the same kind of moment is more developmentally meaningful than constant background music.
When Silence Is the Right Choice
Music and white noise and ambient sound all have their place. Silence has its place too, and parents sometimes feel they should always be providing audio input.
Useful moments for silence:
After the baby has fallen asleep, if they fell asleep in silence. Adding music after the fact creates a sleep association problem.
During quiet awake time (post-nap, before a feed) when the baby is regulating and observing. Letting them experience the natural ambient sounds of the home — distant traffic, kitchen noises, a parent's footsteps — builds a baseline auditory awareness that constant background music interferes with.
When the baby shows overstimulation cues (averted gaze, splayed fingers, fussiness): turn the music off. The "more is better" instinct is wrong here. Reducing input is the right response.
For at least some of each day. A baby who has had music or white noise on continuously from waking to sleeping is receiving more auditory input than they need, and may be missing the chance to develop comfort with quiet itself.
Sound Machines vs Music Apps: Which Does What
These tools are often grouped together but they do different jobs.
Sound machines (white noise, pink noise, fan sounds, rain): for masking intermittent household noise that would otherwise wake the baby. Most useful in households with thin walls, traffic noise, older siblings, or daytime household activity continuing through naps. Use at low volume continuously through sleep.
Music apps (lullabies, instrumentals, calming music): for the settling phase, for daytime listening, for shared engagement with a parent, and for creating a richer ambient environment than silence in play and feeding zones. Curated apps designed specifically for infant sleep — such as Muna — pre-filter for the slow tempo, instrumental focus, and gentle dynamic range that the developing auditory system responds to, which generic playlists do not.
The two can coexist. A common combination: white noise at low volume through the night, with music used during the bedtime settling phase before the white noise takes over. Or music during daytime naps and silence at night. There is no single right combination — the question is what matches your household's noise profile and your baby's responses.
Setting Up: A Practical Checklist
Take a phone-based decibel reading at the cot, the play mat, and the feeding chair during normal household activity. Note where each one sits.
If sleep-zone readings exceed 50 dB during quiet times, identify the source (sound machine too loud, humidifier too close, window too thin, heating vent too noisy) and address it.
Place sound machines at least 1.5–2 metres from the cot and run them at the lowest effective volume.
Decide for each room whether music plays continuously, intermittently, or not at all. A coherent acoustic plan beats ad hoc reactions.
Audit any noisy toys with the same decibel app. Anything reading above 75 dB at infant ear distance is too loud.
Build silence into the day. Continuous audio input is not the goal.
The acoustic environment is one of the few aspects of early life over which parents have a lot of control and which has measurable effects on sleep, feeding, and developmental experience. A few adjustments — a sound machine moved further from the cot, a noisy toy retired, a quieter feeding chair — can shift the texture of a baby's day in ways that show up in better sleep, calmer feeds, and a more regulated baby overall.
Key Takeaways
The acoustic environment in which a baby spends their day is one of the most overlooked variables in early development. The recommended ceiling for sleep-environment sound is 50 dB — quieter than most parents assume — and the JAMA Pediatrics 2014 study by Hugh and colleagues found that many sound machines on the market exceed safe levels at the volumes and distances typically used. Decibel meter apps on a phone are accurate to within 2–3 dB and are sufficient for setting a baseline. Different rooms in a home call for different acoustic strategies: a calm sleep room (under 50 dB, soft furnishings, music or silence by preference), a moderately stimulating play space (under 65 dB, varied content), and a focused feeding zone (low and stable). Knowing when silence is preferable to music — and when sound machines are doing more harm than good — is more useful than any single piece of gear.
