It's personal. Green noise sounds like a calm river or soft surf and feels natural; brown noise is a deeper rumble that many find grounding. Both can help you sleep by masking sudden sounds — try each at low volume and keep whichever you stop noticing first.
Green and brown noise are the two colors people reach for when white noise feels too harsh. They're both soothing, both broadband, and both wildly popular — but they sit in different places on the spectrum, and that changes how they feel.
The quick comparison
| Green noise | Brown noise | |
|---|---|---|
| Sounds like | A flowing stream, soft surf, a breeze | A deep rumble, heavy waterfall, distant thunder |
| Energy sits in | The middle frequencies | The low frequencies (even more than pink) |
| Feels | Natural, balanced, "outdoorsy" | Deep, warm, enveloping |
| Often chosen for | Sleep, relaxation, a nature feel | Focus, deep calm, blocking low rumble |
How they actually differ
Green noise emphasises the mid-range, which is why it reads as nature — think of the even wash of a river. It's soft without disappearing entirely, so it's a common pick for people who want something gentle but present while falling asleep.
Brown noise (also called red noise) pushes the most energy into the low end, producing a rolling, bassy rumble. It's the deepest and often the "warmest" of the common colors, which is why it's become a favourite for focus and for people who find higher frequencies distracting or even irritating.
Rule of thumb
- Want it to feel like being outside? Lean green.
- Want it to feel like a deep, cozy blanket of sound? Lean brown.
Which is better for what
- Falling asleep → personal, but both work; green if you like a nature wash, brown if you want deep and dark. Keep the volume low.
- Focus and study → brown tends to win; its even low rumble slips into the background. Green can work too if brown feels too heavy.
- A racing mind at night → many people find brown's depth more grounding, but green's gentleness suits others. Try both.
- Masking traffic or a noisy building → brown is excellent at burying low rumble; green handles mid-range chatter well.
What the evidence says
Neither green nor brown noise has much direct, high-quality research — most of the solid work is on white and pink. A 2021 systematic review found the overall evidence for noise as a sleep aid is limited and mixed,1 and the strongest single finding remains pink noise's link to deeper sleep in older adults.2 So treat "green vs brown" as a question of preference, not medicine — the best one is the one your brain stops noticing fastest.
There's no winner here, only a fit. Play both for two minutes each at low volume; keep whichever you forget is playing.
Evidence tier: Promising. Broad support for background sound and masking; little research on these two colors specifically. Choose by feel. How we rate evidence →
References
- Riedy SM, Smith MG, Rocha S, Basner M. Noise as a sleep aid: a systematic review. Sleep Med Rev. 2021;55:101385. doi:10.1016/j.smrv.2020.101385.
- Papalambros NA, Santostasi G, Malkani RG, et al. Acoustic enhancement of sleep slow oscillations and concomitant memory improvement in older adults. Front Hum Neurosci. 2017;11:109. doi:10.3389/fnhum.2017.00109.