When White Noise Makes It Worse

The research behind the app's most important design decision

White noise is the default sleep-sound recommendation almost everywhere — pediatricians mention it, sleep apps ship with it on, and it genuinely helps a great many children mask a noisy house. For autistic children, it's a coin flip, and the evidence is specific enough to name a number.

The study

Between February 2023 and July 2024, a hospital in Barcelona offered white noise through headphones to 54 children and adolescents, ages 7–17, when staff observed signs of restlessness — split into two groups: 21 autistic children without an intellectual disability (average age 13.3), and 33 with a co-occurring intellectual disability (average age 9.9).

The results split sharply by group. In the group with an intellectual disability, tolerance was 100%, and the average duration was 15.3 minutes. In the group without one, tolerance was 57.2%, for an average of just 3.4 minutes — meaning 9 of the 21 children (42.8%) would not tolerate white noise at all. The difference between groups was statistically significant.

The limits of this study

It's fair to name the limitations plainly: there was no control group, it was a single exposure rather than a trial over time, and the sample was small and unevenly split between groups — the authors themselves note the possibility of regression to the mean. This is real evidence, not proof of anything universal. But it lines up with a wider, more established pattern: hyperacusis — discomfort at ordinary volumes — is measured at 18–69% across autism studies, several times the 3–17% seen in the general population, however it's counted.

Why pink noise is the gentler default

In audiology practice for sound sensitivity, pink noise is generally preferred over white for exactly this reason: it carries less energy at high frequencies, which tends to make it less irritating to a sensitive ear. In more severe cases of hyperacusis, it's sometimes filtered even further, cutting frequencies above roughly 5 kHz — a "softened" pink noise.

That's a specific, testable reason this app puts pink noise directly next to white noise in the Sound Mixer, rather than treating white noise as the obvious default. Neither one is chosen for your child in advance — every ambient sound starts at zero.

Nature sounds rank higher still

A 2024 study went a step further than pink-versus-white and asked autistic adults to rate a range of sound-masking options directly. The result was clear: nature sounds — water, rain — were rated the most preferred masking category, ahead of white noise, brown noise, and every colored-noise variant tested. The sample skewed toward more independent autistic adults, so it shouldn't be read as universal, but it lines up with what audiology already recommends for gentler masking — and it's a reason to try rain or ocean waves before assuming any noise texture is needed at all.

Sounds worth extra care in a mixer built for sensitive listeners

• Anything with deliberate irregularity — glitchy or artifact-heavy textures are, by definition, exactly the kind of unpredictable, sudden acoustic event that a sensitive auditory system reacts to most strongly.
• Sharp rhythmic impacts — a marching or drumming sound with a hard attack combines an abrupt onset with a driving, insistent rhythm.
• Ticking sounds — a classic trigger for misophonia (a strong aversive reaction to specific, particular sounds, distinct from hyperacusis), which is also documented in autism. Not a reason to remove ticking entirely, but a reason it should never sit in a default preset.
• Low, soft-onset sounds — a heartbeat, gentle rain, ocean waves and similar textures generally sit at the gentler end and are reasonable starting points to try first.

How to actually test a sound

The single most repeated piece of practical advice across the research and clinical practice is the same: assess before you deploy, and start with what's likely to be pleasant.

1. Test during the day, never at bedtime. Bedtime is the worst possible moment to discover a sound is unbearable — you're tired, your child is tired, and there's no room to back off gracefully.
2. Play one sound at a time, briefly. A few seconds is enough to see a reaction. Resist the urge to build a "complete" mix on the first try.
3. Start with soft, low-onset sounds before trying anything sharper or more textured — the audiology approach to hyperacusis training follows the same order.
4. Let your child veto anything, without needing to explain why. A "no" here is data, not a problem to solve.
5. Save what works as a preset so the evening only has to run the routine, not decide it from scratch. The app's Sound check (in the menu) walks you through these steps: six gentle sounds, one at a time, quietly, and the ones you mark are saved as Custom 1.