Sound machines help sleep mainly through masking: steady background noise covers up sudden, attention-grabbing sounds that would otherwise wake you. The research shows white noise improves sleep quality and sleep-onset latency, especially in noisy environments. Brown noise is deeper and 'rumbly', pink noise is between the two, and for tinnitus, sound therapy (including pink noise) is a real, evidence-supported approach — though it manages the perception rather than curing it. Comfort with the sound matters more than the exact color.
Sound machines went from a baby-shower staple to a mainstream sleep accessory, and the 'colors' of noise now have their own vocabulary — white, pink, brown, and the internet's deep-dive debates about which is superior. Here's the science that actually explains them, and what it means for your night.
Why noise helps you sleep: masking
The core mechanism is called masking, and it's simpler than the marketing. Your brain is wired to wake for sudden changes in sound — a door slam, a car backfiring, a partner's snore. Steady background noise raises the 'floor' of the soundscape, so those sudden events no longer stand out enough to trigger an arousal. It's the same reason rain is soothing and a silent room can feel louder than a noisy one: the steady sound hides the surprises.
The research supports the practical benefit. A 2021 review of white noise in a high-noise environment found it improved sleep — and a 2026 randomized trial in older adults found white noise improved sleep quality and reduced fatigue. The evidence is strongest when there's something to mask: a noisy street, a snoring partner, thin walls.
White, pink, or brown: does it matter?
White noise contains all frequencies at equal intensity — it's the classic 'shhhh' hiss. Pink noise is deeper, with more low-frequency power, and many people find it warmer and more natural. Brown (or red) noise is deeper still — the rumble of distant thunder or a plane cabin. The research hasn't crowned a winner; the important variable is that you find the sound comfortable and it masks what's bothering you. A machine with a few options, or an app with different colors, lets you just try them. The 'which is superior' debates online are mostly preference, not science.
White noise and tinnitus
A genuinely important application is tinnitus — a persistent ringing or hissing that can make quiet bedrooms unbearable. Sound therapy is an established approach: providing background sound (often pink or white noise) reduces the contrast between the tinnitus and the silence, so the ringing is less noticeable and less distressing. One 2023 study described pink noise as a potential sound therapy for tinnitus. It doesn't 'cure' the ringing — it changes how much it bothers you, which for many people is the entire point. If tinnitus is affecting your sleep, this is one of the few things with real evidence behind it.
A sound machine doesn't create silence. It makes the silence less surprising.
Choosing and using a sound machine
- Volume matters. Loud enough to mask the problem, quiet enough that the noise itself isn't the distraction. If you can hear it clearly over everything, it's probably too loud.
- Comfort beats specs. The best color is the one you can fall asleep to without noticing. Try a few.
- Consistency helps. A steady sound all night (or a timed fade-out) is better than one that stops abruptly mid-sleep.
- For tinnitus, dedicated sound therapy — matched to your ringing, often pink noise — is more targeted than a generic machine.
Where SleepTrace fits
A sound machine changes what your night sounds like — which is exactly what SleepTrace can show you. SleepTrace records your night with just your iPhone and lays the audio over your sleep stages, so you can see whether a white-noise night actually reduced your wake-ups and deepened your sleep. Try a week with and without, and compare the nights. Start with sleep sounds that help, or read overstimulation if noise sensitivity is your issue.
References
- Ebben MR, Yan P, Krieger AC. The effects of white noise on sleep and duration in individuals living in a high noise environment. Sleep Med (2021). Europe PMC
- Lai H, Wang G, Zheng Z, et al. Pink noise: a potential sound therapy for tinnitus. Am J Transl Res (2023). Europe PMC
SleepTrace is a wellness app, not a medical device. This article is general information, not medical advice. If your symptoms are frequent, severe or worrying, please talk to a doctor.
Hear your own night. SleepTrace turns a night of audio into your sleep phases, the sounds you made, and how it all trends — no wearable, just the iPhone on your nightstand. Download on the App Store →