The colours of noise, explained

You’ve probably heard that noise comes in “colours” — white, pink, brown, and now green — but the names can seem arbitrary until you know what they’re describing. They’re not about how the noise feels so much as a precise, physical fact: how the sound’s energy is spread across the range of frequencies you can hear. That single difference is why white noise sounds sharp and brown noise sounds deep, and it’s what makes each one suited to a different job.

01What “colour” actually means

Human hearing spans a wide range of frequencies — very roughly from 20 Hz (a deep rumble you feel as much as hear) up to 20,000 Hz (a high, thin hiss). Any noise contains a mixture of all these frequencies at once. What changes from one colour to another is the balance: how much energy sits in the low frequencies versus the high ones.

The colour names borrow from light, where white light contains all colours mixed evenly. White noise is the audio equivalent — every frequency at equal power. The other colours are named by analogy for how their balance is tilted. It’s the same idea as an equaliser: shift the energy toward the bass and the sound gets deeper and warmer; shift it toward the treble and it gets brighter and sharper. That tilt is the whole story, and it’s why each colour feels so different and suits a different use.

02White noise — equal at every frequency

White noise has equal power in every frequency band across the audible range. Because our ears are more sensitive to higher frequencies, that even spread sounds bright and hissy — think of static, or the airy rush of an untuned radio. It’s the sharpest of the colours.

That brightness is exactly what makes it a strong masker: with energy spread everywhere, it covers a wide range of intruding sounds at once, giving your brain something steady and neutral to settle on instead. Many people find it blocks out distractions well, which makes it popular for sleep and for concentrating in a noisy space. Some find it a little harsh over a long night — which is where the warmer colours come in.

03Pink noise — softer at the top

Pink noise has less energy at higher frequencies than white — the treble is rolled back, so the balance tips gently toward the lows. The result is a “fuller,” softer sound that most people find easier on the ear than white noise while still masking effectively. It’s often described as more natural, and for good reason: many sounds in nature are close to pink. Rustling leaves, steady wind, and even the rhythm of a heartbeat sit in that balanced, low-leaning territory.

If white noise feels too sharp but you still want broad masking, pink is the natural middle ground — warmer and rounder, without going all the way down to a deep rumble.

04Brown noise — deep and booming

Brown noise (named after Brownian motion, not the colour) tilts even further toward the low frequencies. With most of its energy down in the bass, it has a deep, soft, “booming” quality — like a distant waterfall, heavy rain on a roof, or the low roar of a jet cabin. It’s the darkest and most enveloping of the colours.

That depth is why brown noise has become so popular for relaxation and sleep: it’s grounding and steady, with none of white noise’s hiss, and it masks low, rumbling disturbances especially well. Many people who find other noise colours too bright settle on brown as the one that lets them switch off. It pairs beautifully under rain, too — the article on brown noise vs. white noise goes deeper on the sleep comparison.

05Green noise — the middle of nature

Green is the newest colour to catch on, and it has a specific character: its energy is concentrated in the mid-range frequencies, rather than spread evenly or pushed to the extremes. The idea is that this mimics the spectrum of natural, outdoor ambience — the broad background hush of the world without the sharp highs of human-made noise or the heavy lows of a rumble. It sits, quite literally, in the middle.

Because of that mid-focused balance, green noise is often described as especially calming and “natural,” like distant water or wind heard from far off. It’s also sometimes used in sound masking for tinnitus, where a gentle mid-range wash can help take the edge off the ringing without adding harshness. EverLull generates green noise live alongside the others, so you can compare all four back to back.

06Which one for you

There’s no “best” colour — it depends on the job and on your own ear. A rough guide:

The honest advice is to try them. In EverLull all four are free, generated live so they never loop, and you can layer them or blend them with rain and ocean to find what settles you. Start with one, sit with it for a few minutes, and switch if it doesn’t feel right — your ear will tell you quickly. For how sound helps in the first place, see sound, stress, and the nervous system.

07Questions, answered