The three noise colors, explained
“Noise color” describes how a sound's energy is spread across frequencies. White noise has equal energy at every frequency — it's the classic hiss of an untuned radio. Pink noise shifts more energy toward lower frequencies, so it sounds fuller and softer, closer to steady rainfall. Brown noise (sometimes called red noise) goes further still, weighted heavily toward the low end, producing a deep, rumbling sound closer to a distant waterfall or a low fan.
All three mask sound by the same basic mechanism — they raise the room's overall noise floor so smaller, sharper sounds don't stand out — but they differ in how the masking feels, and in how much research actually backs each one.
What the research actually supports
White noise has the longest track record: it's been studied for decades as a general masking tool and is commonly recommended for infant sleep and light sleepers in noisy environments.
Pink noise has the most direct sleep-specific research of the three. Studies on pink noise during sleep have found it associated with deeper, more stable slow-wave sleep in some groups, particularly older adults — though results vary and it isn't a guaranteed effect for everyone.
Brown noise is the newest to go mainstream, largely through social media, and currently has the least dedicated research behind it relative to how popular it's become. That doesn't mean it doesn't work for the people who swear by it — preference and habit matter a lot here — just that the evidence hasn't caught up to the hype yet.
Which one should you use
As with rain versus white noise, there's no universal winner — there's the sound your nervous system stops noticing. If you want the strongest, most even masking and don't mind a clinical sound, white noise is hard to beat. If you want something softer for long sessions, pink noise is the usual recommendation. If you're drawn to a deep, low rumble, brown noise may suit you best, even without the research base to match the buzz.
The only real way to know is to try each for a few nights (or work sessions) in a row, at a consistently low volume, and notice how you actually slept or focused — not how the sound felt in the first thirty seconds.
Where Calming Galaxy's sounds fit in
Calming Galaxy's library is built from real recorded nature sounds — rain, rivers, ocean waves — rather than synthesized noise-color generators. That's a genuine difference: nature recordings carry natural texture and gentle variation that pure tones don't, while still landing in a similar part of the frequency spectrum.
Rain and River, in particular, sit close to pink noise's frequency profile: fuller in the low-to-mid range, softer at the top, and closer to weather than to static (see our rain vs. white noise guide for more on this). If you specifically want a pure, synthesized noise-color track, that's not what this library offers today — but if you want something in a similar masking range with more natural texture, Rain or River is the closest match, and both are mixable with the rest of the library.
Noise color, focus, and ADHD
Some research has looked at whether background noise affects attention differently for people with ADHD, with a few studies finding a modest benefit from steady white or pink noise for sustained attention in ADHD groups specifically — an effect not generally seen in people without ADHD. Brown noise's reputation as a focus tool is currently running well ahead of its research base; anecdotal reports are strong, but there isn't the same body of controlled study behind it yet.
If you're testing sound for focus rather than sleep, our guide to the best sounds for focus covers how to build a mix that stays in the background instead of becoming its own distraction — River and Rain are a reasonable starting point if you're curious whether a pink-noise-adjacent sound helps.
Hear it for yourself
These guides are easier to act on than to read. The sounds they reference each have their own page — the ones marked Free play right there on the site.
