What the color labels actually measure
Each label is a shorthand for a shape on a graph of power against frequency. The Sleep Foundation defines white noise as containing all frequencies across the spectrum of audible sound in equal measure, which is why it is also called broadband noise. The same source describes pink noise as 1/f noise and says individual pitches decrease by 3 decibels with each higher octave. Brown noise falls away faster still, with a decrease the Sleep Foundation describes as twice as great as pink noise's. Nothing about the labels implies a benefit. They are descriptions of spectral shape.
What each one sounds like
White noise is the one people compare to the static from an untuned radio or television, and the Cleveland Clinic goes further, calling it busy, frazzled and all over the place. Pink noise sits in the middle, and the comparison both the Sleep Foundation and the Cleveland Clinic reach for is a waterfall, along with rain, wind, a river and ocean waves. Brown noise is the deep one: the Cleveland Clinic's examples are waterfalls, thunder, crashing waves, showers, heavy rain and wind through trees, and in research trials people have said brown noise reminds them of rainfall or a shower. The practical consequence is simple. As the roll-off gets steeper, the hiss recedes and the rumble comes forward.
Is one color better for sleep?
Not on the evidence available. A 2021 systematic review in Sleep Medicine Reviews assessed 38 articles on continuous broadband noise and sleep and found enough heterogeneity in noise characteristics, measurement and adherence that the extremes of the literature were that continuous noise improves sleep and that it disrupts it. Against the GRADE criteria the quality of evidence for continuous noise improving sleep was very low. Pink noise has attracted the most sleep and memory research of the three, and those results are best described as initial rather than settled. Brown noise's effect on sleep has not been widely studied at all. So the honest answer to which color is best is that the research does not name one.
How to pick one without overthinking it
Given that the evidence does not separate the colors, preference is a reasonable tie-breaker, and comfort predicts whether you keep using a sound at all. Two practical constraints do have numbers behind them. The first is volume: the Cleveland Clinic advises listening at lower volumes in brief periods of 10 to 15 minutes, and using a timer at bedtime so your ears recover before you fall asleep. The second is that whatever you play should not need managing. A track that ends, cross-fades badly or drops into an ad will pull you back out of the state you were trying to reach. Set the level once, set a timer, and stop auditioning colors.
In short
- The color names describe spectral shape: white is flat, pink rolls off about 3 dB per octave, brown roughly twice as steeply.
- Perceptually the steeper the roll-off, the less hiss and the more rumble.
- A 2021 review of 38 studies rated the evidence for continuous noise improving sleep as very low quality.
- Pink noise has several small sleep studies behind it, and those findings are still initial.
- Volume and a timer matter more than which color you choose.
Related guides
- Brown noise vs white noise: White noise carries equal power across every audible frequency, so it reads as a bright, even hiss.
- Brown noise: Brown noise is broadband sound weighted heavily toward low frequencies, so it comes across as a deep rumble rather than a hiss.
- Pink noise vs white noise: White noise holds every audible frequency at equal power, so it sounds higher-pitched, like a humming air conditioner.