Noise Generator
White, pink, brown, blue and violet noise, generated sample-by-sample rather than filtered from a loop — with adjustable low-cut and high-cut shaping, a sleep timer that fades out gently, and presets for sleep, focus, a nursery, tinnitus relief and office masking.
Quick Tips for Getting It Right
Features
What "Color" Actually Means for Noise
Noise colors are named the way they are because of a genuine, if loose, analogy to light — white noise, like white light, carries equal energy across every frequency simultaneously. Pink and brown both shift that energy toward the lower end: pink loses about 3 decibels of energy every time the frequency doubles, brown loses about twice that, which is why pink sounds like a steady rush of water and brown sounds like a deep, room-filling rumble with almost none of white's sharper hiss left.
Blue and violet run the relationship in reverse, gaining energy as frequency rises instead of losing it — blue is brighter than white, violet sharper still. They're used far less often for sleep, since that rising top end is the opposite of relaxing, but they have real, specific uses: violet noise in particular shows up in audio dithering and is occasionally used experimentally for tinnitus that sits at a higher pitch than typical broadband noise reaches.
Real Noise, Not a Filtered Recording
A common shortcut for building a "noise generator" is to take plain white noise and run it through one lowpass filter to fake pink or brown — the result technically has less high-frequency content, but it doesn't actually reproduce the real spectral slope, and tends to sound noticeably duller and flatter than genuine pink or brown noise rather than warm. This tool runs the real algorithms instead — Paul Kellett's multi-stage pink noise filter and a leaky-integrator for brown, both computed one sample at a time inside an AudioWorklet — with blue and violet derived mathematically as the exact spectral opposites of pink and brown.
Left and right channels are also generated completely independently rather than copying one channel and panning it — a mono noise source panned wide reads as flat and "in your face" compared to genuinely decorrelated stereo, which is a large part of why some free noise generators sound harsher than others playing what's nominally the same noise color.
Shaping It to the Room
Every noise color still carries content across the full audible range by default, and not every room, speaker or set of headphones handles that the same way — a laptop speaker with weak bass response might make brown noise sound thin, while the same color through a subwoofer-equipped setup can feel overwhelming. Low Cut and High Cut exist specifically to trim that mismatch: pulling Low Cut up removes rumble a small speaker can't reproduce cleanly anyway, and pulling High Cut down softens hiss that feels sharp on sensitive ears or in-ear headphones, without needing to abandon the color that otherwise sounds right.
The two filters also make it possible to land somewhere between two named colors rather than being locked into one. Brown noise with High Cut pulled well down sounds noticeably different from brown with the full range left open — closer to a distant, muffled rumble than the fuller tone the unfiltered color has by default. There's no need to treat the five presets as five fixed destinations; they're a reasonable starting point for a much wider range of actual results.
Who Actually Leaves This Running
People with trouble sleeping through household or street noise use it as a steady background layer that's easier for the brain to tune out than unpredictable sounds. Open-plan office workers and students in shared spaces use it to mask nearby conversation without needing headphones playing actual music, which can be its own distraction. Parents run a nursery preset to help a baby settle and stay asleep through a noisy household. And people managing tinnitus use a steady broadband color as part of a broader sound-therapy approach recommended by audiologists.
Two Ways People Actually Use It
Someone falling asleep to noise most nights picks Brown, trims Low Cut up slightly to avoid the deepest rumble bleeding through a thin apartment wall, sets the 60-minute sleep timer so it fades out on its own, and checks the Sleep Calculator beforehand to work out roughly when to actually start winding down for a full night's rest.
A student studying in a busy shared library instead picks Pink at a moderate volume specifically to mask nearby conversation, running it alongside a Pomodoro Timer so the noise and the study session start and stop together rather than needing to be managed separately across two different habits.
What Noise Can't Fix
Masking noise makes an inconsistent, jarring sound environment more tolerable by replacing it with something steadier and more predictable — it doesn't actually block or reduce the volume of anything, which is a meaningful distinction from earplugs or genuine soundproofing. A loud enough disruption will still cut through any noise color at any reasonable volume, since the goal is providing a comfortable, unchanging texture to tune out against, not physically stopping other sound from reaching your ears.
It's also not a treatment for sleep disorders, anxiety or tinnitus on its own, however often it gets used alongside managing all three. Treated as what it actually is — a genuinely well-built, flexible sound-masking tool — it holds up well against paid apps offering the same basic idea with a subscription attached.
It's also worth being clear that sound masking and active noise cancellation are different tools solving different problems. Noise-cancelling headphones use a microphone and inverted sound wave to physically reduce how much outside sound reaches your ear in the first place — genuinely subtracting noise. This generator adds a steady, predictable sound instead, which doesn't reduce anything but makes what's already there easier to ignore. The two aren't competing approaches; a pair of noise-cancelling headphones playing a masking tone through them is a common and reasonable way to combine both.