Online Noise Generator

Listen safely. The volume starts at 20 % on purpose. Noise has no melody to warn you that it is loud, so it is very easy to creep the level up over an evening. Turn your system volume down before you press Play, then raise it slowly until the noise just covers what you are masking — no louder. For overnight use keep it quiet enough that you can still hear someone speak normally in the room, and prefer a speaker to headphones. Blue and violet noise are bright and fatiguing; keep those well below the level you would use for brown.

Mouse

• Play / Stop — starts and stops the noise with a 200 ms fade, so it never clicks.
• Colour buttons — White, Pink, Brown, Blue, Violet. Click while the noise is playing to A/B them instantly; the swap is crossfaded over 60 ms and the spectrum redraws immediately so you can see the slope change.
• High-pass — 20–2000 Hz, removes everything below the setting (12 dB/octave). Raise it to strip rumble.
• Low-pass — 200 Hz–20 kHz, removes everything above the setting (12 dB/octave). Lower it to soften hiss.
• Tilt — −12 to +12 dB. A single tone control that pivots the whole spectrum around 1 kHz: negative is darker, positive is brighter.
• Band presets — Full, Sleep, Masking, Rumble and Air set the two filters and the tilt in one click.
• Drag on the plot — three round handles sit on the spectrum. HP and LP slide sideways along the frequency axis to move the two cutoffs; TILT drags up and down to brighten or darken. The sliders follow the handles and the handles follow the sliders. Everything has a 30 px grab radius, so it works with a fingertip.
• Volume — master level, 0–100 %. Changes are ramped over 60 ms.
• Timer — Off, 5, 10, 15, 30, 45, 60 or 90 minutes. The countdown runs in the transport bar and the noise fades smoothly to silence over the last stretch, then stops itself.
• Reset — back to pink noise, full band, flat tilt, 20 % volume, no layers, no timer, quiz off.

Soundscape mixer

• Five layers stack on top of whatever base colour you have chosen. Each one has an On/Off button and its own level, and each is a genuinely different filter chain rather than a relabelled copy:
• Rain — white noise high-passed at 1 kHz with a +5 dB lift at 4 kHz, the corner drifting on a 0.09 Hz oscillator so it never sits still.
• Ocean — brown noise under a low-pass that a 0.05 Hz oscillator sweeps between about 250 Hz and 1.35 kHz, with an amplitude swell on the same period. That is the surf.
• Wind — pink noise through a Q 1.4 bandpass drifting between roughly 180 and 660 Hz, gusting on a second, faster oscillator.
• Rumble — brown noise low-passed at 300 Hz with a +9 dB shelf below 120 Hz. Steady and very deep.
• Hum — a narrow Q 7 resonance at 110 Hz with a slow beat, the sound of a fan or an engine.
• Turning a layer up while the mix is stopped still redraws the spectrum: the preview curve is the power sum of the base colour and every audible layer, so you can build a soundscape silently.
• Layers feed the same band shaping as the base colour, so the high-pass, low-pass and tilt shape the whole mix.

Scenes

• Focus, Sleep, Rain (rain on a window), Deep (deep rumble) and Cabin (airplane cabin) each set the base colour, both filters, the tilt, all five layer levels and the master volume in one tap — you can watch every control move.
• Touch any individual control afterwards and the scene button lets go, because the mix is no longer exactly that scene.

Play mode — Name that noise

• Entirely optional; the plain generator never needs it. Start quiz flattens the band, mutes the layers and plays one of the five colours at random with the spectrum covered, so the only clue is what you hear.
• Pick a colour button to answer. You get an instant right or wrong, the plot is uncovered so you can see the slope you just judged, and the score, current streak and best streak update.
• Replay re-triggers the same mystery noise from a new point in the loop; Next noise deals another round; Exit quiz puts your own mix back exactly as you left it.

Phase timer

• 25/5 and 50/10 are repeating cycles: noise for the focus block, then a silent break that keeps counting, then noise again, until you press Stop. The last 12 s of each focus block fade out so the break does not arrive as a jolt.
• Nap 10 and Deep 45 run once and stop themselves, fading over the last 30 s.
• The current phase and its countdown are shown both on the chip under the timer and in the transport bar, so you always know whether you are in Focus or in Break.
• Choosing a phase programme switches the plain minute timer off, and choosing a minute value switches the programme off. Press Play during a break to restart the cycle from the first focus block.

Touch

• Every button is at least 42 px tall and all button grids wrap — nothing is hidden in a sideways scroller.
• Drag any slider thumb; the value above it updates as you move.
• Drag the HP, LP and TILT handles on the spectrum itself. The plot swallows the scroll gesture only while you are actually holding a handle.
• Tap Fullscreen for a large spectrum on a phone or tablet.

Keyboard

• Space start / stop.
• ← → previous / next noise colour — the fastest way to A/B them.
• ↑ ↓ volume ±5 %.
• 1–5 pick White, Pink, Brown, Blue or Violet directly.
• [ ] tilt darker / brighter  ·  T cycle the timer  ·  P cycle the phase programme  ·  R reset.
• Q start or exit the quiz  ·  N next round. During a round 1–5 are your answer and the arrow keys are ignored so you cannot stumble into one.
• Shortcuts are ignored while a slider or a text field has focus, so native slider and typing behaviour still work. Click the widget background first, then use them.

What each colour is, and what it is for

• White — flat, 0 dB/octave. Equal power at every frequency, so equal power per hertz. It sounds bright and hissy because each higher octave is twice as wide and therefore carries twice the energy. Used for speaker and room testing, for dither, and for hard masking of high-pitched sounds such as a whining fan.
• Pink — −3 dB/octave. Equal power in every octave, which is how we perceive balance, so it sounds the most natural and "full". This is the usual first choice for sleep, concentration and tinnitus relief, and it is the standard reference signal for room tuning. Generated here with the Voss/Kellet six-pole filter, not by relabelling white noise.
• Brown (red) — −6 dB/octave. Made by integrating white noise with a small leak term, which is literally a random walk. Deep and soft, like heavy rain, a waterfall or distant surf. The least fatiguing over long periods and the best at covering traffic, footfall and low-frequency neighbour noise.
• Blue — +3 dB/octave. The mirror image of pink, made by differentiating pink noise. Bright and airy. Used in high-quality dithering and in some tinnitus-therapy protocols that deliberately stimulate the high frequencies.
• Violet (purple) — +6 dB/octave. The mirror image of brown, made by differentiating white noise. A thin, sharp hiss with almost no body. Used for tweeter testing and for masking very high-pitched tinnitus. Keep it quiet.

Reading the spectrum

• The horizontal axis is frequency on a log scale, 20 Hz to 20 kHz, so every octave takes the same width. The vertical axis is level in dB, 20 dB per gridline.
• Because octaves are evenly spaced, a constant dB/octave slope is a straight line. The dashed grey line is the ideal slope for the colour you have selected — the live trace should sit along it.
• The trace is measured after the filters and the tilt but before the volume control, so turning the volume up and down does not move it. Changing the high-pass, low-pass or tilt does.
• Before you press Play the display shows a calculated preview of the same curve, so you can shape the band silently first.

Tips

• Mask a specific noise, don't drown it. Set the low-pass to just above the sound you are covering — about 500 Hz for traffic and footfall, about 4 kHz for speech from the next room — then raise the volume only until the intruding sound stops standing out. A narrower band at a lower level masks better than full-range noise turned up.
• For sleep, start on brown or pink with the Sleep preset and a 45-minute timer. The long fade means you drift off while it is still audible and the room is quiet by the time you are in deep sleep, which avoids the sudden silence that can wake you.