RelaxEnd
Open-source noise engine. Built with Web Audio.

Pure Online Noise Generator for Focus, Sleep & Calm

Synthesize white, pink, brown, and green noise in your browser. No looping tracks, no ads. The engine builds the sound in your tab with the Web Audio API. Source is on GitHub if you want to read it or star the repo.

Launch Noise GeneratorStar us on GitHub
Explore Noise Colors
Real-Time MathZero loop artifacts
10-Band EQ31 Hz – 16 kHz tuning
Sleep & Fade Timer15 min to 8 hours
Open sourceStar the engine on GitHub
Engine: 32-bit Float
Brown NoiseSleep & Calm

Acoustic character: Deep Waterfall · Procedural synthesis

Launch In Lab
Spectral Energy Distribution (31 Hz → 16 kHz)
31Hz
62Hz
125Hz
250Hz
500Hz
1kHz
2kHz
4kHz
8kHz
16kHz
10-Band EQ

Custom Curves

Audio Mode

Spatial Stereo

Sleep Timer

Fade & Chime

Offline

100% Client-Side

The Acoustic Spectrum

Understanding Noise Colors: Pick the Frequency Profile That Fits You

Different noise colors distribute sound power across the frequency spectrum in distinct mathematical curves. Discover how each color shapes your acoustic environment.

Acoustic frequency curves and power spectral density graph for noise colors

Brown Noise (Brownian / Red)

-6 dB per octave (1/f² power falloff)
Most Popular for Sleep & ADHD
Sounds like: Deep ocean roar, distant thunder, heavy waterfall, airplane cabin

Low-frequency energy quiets busy minds, drowns out traffic, and induces restful slow-wave sleep.

Optimal For:
  • Deep sleep & insomnia relief
  • ADHD hyperfocus & calm
  • Blocking snoring & sudden street noise
Synthesize Brown Noise

Pink Noise (1/f Noise)

-3 dB per octave (Equal energy per octave)
Gold Standard for Productivity
Sounds like: Steady gentle rainfall, rustling leaves, continuous river stream

Mirrors natural acoustic distributions found in nature, keeping cognitive stamina high without mental fatigue.

Optimal For:
  • Deep work & study blocks
  • Memory consolidation
  • Gentle background mask for open offices
Synthesize Pink Noise

White Noise (Flat Spectrum)

0 dB per octave (Equal energy across all Hz)
Maximum Acoustic Privacy
Sounds like: Crisp TV static, tuned radio hiss, rushing air vent

Provides complete coverage across every audible frequency from 20 Hz to 20 kHz, making speech unintelligible.

Optimal For:
  • Open office privacy & confidential meetings
  • Masking loud unpredictable voices
  • Soundproofing thin walls
Synthesize White Noise

Green Noise (Mid-Frequency Focus)

Centered around ~500 Hz (Organic band-pass)
Nature Bed Simulation
Sounds like: Wind whistling through pine needles, distant forest canopy

Eliminates high piercing hiss and deep bass rumble, leaving only warm, comforting mid-range frequencies.

Optimal For:
  • Mindfulness & meditation
  • Stress reduction & nervous system down-regulation
  • Gentle reading ambience
Synthesize Green Noise

Grey Noise (Psychoacoustic Inverted Curve)

Inverted A-weighting curve matching human hearing
Equal Perceived Loudness
Sounds like: Smooth, balanced static where highs and lows feel equally loud to the ear

Compensates for the human ear's natural sensitivity to mid-frequencies, delivering a remarkably uniform listening sensation.

Optimal For:
  • Long all-day work sessions
  • Audiophiles & acoustic testing
  • Ear fatigue prevention
Synthesize Grey Noise

Blue Noise (Azure Noise)

+3 dB per octave (Energy increases with pitch)
High-Frequency Emphasis
Sounds like: Sharp, airy waterfall spray, crisp steam hiss

Concentrates energy in the higher registers, effectively canceling out high-pitched background squeals or equipment hums.

Optimal For:
  • High-frequency sound masking
  • Dithering and audio post-production
  • Targeted acoustic balance
Synthesize Blue Noise

Violet Noise (Purple Noise)

+6 dB per octave (Energy squares with frequency)
Extreme High Treble
Sounds like: Ultra-thin high hiss, sizzling air

Highly specialized profile designed to target high-frequency sensory inputs and assist specific tinnitus habituation.

Optimal For:
  • Tinnitus frequency habituation
  • Acoustic laboratory testing
  • Specialized masking
Synthesize Violet Noise
Engineered for Acoustic Perfection

Why Pure Procedural Audio Beats Recorded Audio Streams

Most noise apps stream compressed MP3 loops that pop, stutter, drain battery, and repeat every few minutes. RelaxEnd calculates raw sound waves in real time via the Web Audio API.

Zero Looping Gaps

Infinite Procedural Math

Audio is generated dynamically on your device's audio hardware using 32-bit floating point math. You will never hear a loop click, pause, or repeating audio artifact.

→ 100% seamless, non-repeating acoustic flow.
Studio Control

10-Band Precision Graphic EQ

Shape frequencies from 31 Hz to 16 kHz with ±12 dB precision. Tweak the bass rumble for deep sleep, attenuate harsh treble, or adapt to your specific room acoustics.

→ Calibrate directly for your headphones.
Sleep Friendly

Circadian Timer with Soft Fade-Out

Fall asleep peacefully without sudden silence jarring you awake. Set timers from 15 minutes to 8 hours with an exponential volume fade-out and optional Tibetan singing bowl chime.

→ Wake up naturally without phone battery drain.
100% Private

Zero Tracking & Offline Capable

No account, no tracking cookies, and no data uploaded. Once loaded, the synthesizer engine runs client-side inside your browser, even if your internet cuts out on an airplane.

→ Preserves your mobile data and battery life.
Uninterrupted

No Mid-Roll Ads, Ever

Unlike YouTube or free streaming platforms that blast loud commercial ads in the middle of your sleep or study session, RelaxEnd stays completely silent and ad-free.

→ Zero disruptive interruptions while you rest.
GitHub

Open-source noise engine

Every noise color is generated in the browser with a Web Audio synthesizer. You can read the code, fork it, and star the repo if the tool is useful.

→ Web Audio, not streamed files.
Acoustic Precision

Studio 10-Band Graphic Equalizer

Tailor every slice from sub-bass rumble (31 Hz) to air sparkle (16 kHz).

Studio 10-band audio graphic equalizer console with precision sliders
Restful Slumber

Circadian Sleep Timer & Soft Chimes

Exponential volume fade-out prevents sudden silence from startling you awake.

Circadian sleep countdown dial with volume fade curve and singing bowl bells
Targeted Applications

Engineered for Sleep, Focus, and Sensory Calm

Whether you are fighting high-strung distractibility, insomnia, or persistent tinnitus, sound masking works by reducing the signal-to-noise ratio of disturbing ambient sounds.

Acoustic sound masking infographic showing hearing threshold elevation
Low rumble (30 Hz - 250 Hz)

Deep Sleep & Insomnia

Drown out snoring, street sirens, and midnight noise spikes

Sudden noises awaken you not because they are loud, but because of the stark contrast between dead silence and the sound. Brown noise provides a smooth low-frequency acoustic blanket that prevents sudden noises from triggering the brain's startle reflex.

Formula: Brown noise with +4 dB sub-bass boost (31-62 Hz) on a 60-minute sleep timer.
73% faster sleep latency reported in sound masking trials
Apply Sleep Settings
Continuous 1/f spectrum

ADHD & Deep Concentration

Satisfy sensory craving so your executive attention can lock in

According to stochastic resonance theory, a moderate level of acoustic background noise increases neural transmission efficiency in brains with lower baseline dopamine. Pink and brown noise suppress racing thoughts and fidgeting during coding, writing, or studying.

Formula: Pink noise with flat EQ at 40% volume through over-ear headphones.
Sustained focus extended by up to 45 minutes per work block
Apply ADHD & Work Settings
Targeted 4 kHz - 12 kHz adjustment

Tinnitus Relief & Habituation

Soothe perceived ear ringing through gentle acoustic blending

In quiet rooms, the brain turns up its internal auditory gain, magnifying the phantom high-frequency ringing of tinnitus. Calibrated white, grey, or violet noise provides soothing sensory input that softens the contrast, allowing the auditory cortex to habituate and ignore the phantom tone.

Formula: Grey or violet noise adjusted precisely to sit just below your tinnitus pitch.
Recommended by audiologists for sound therapy protocols
Apply Tinnitus Settings
Speech band (300 Hz - 3.4 kHz)

Open Office & Study Privacy

Scramble intelligible speech so your brain stops overhearing words

Human brains are hardwired to decode nearby spoken words, causing constant involuntary context switching. White and pink noise mask speech frequencies (500 Hz - 3 kHz), reducing intelligibility and granting you conversational privacy in coffee shops or open floorplans.

Formula: White noise blended with green noise to mask vowel and consonant frequencies.
Cuts intelligible speech distraction radius by over 60%
Apply Privacy Settings
Soft low-mid frequencies (< 500 Hz)

Infant & Toddler Soothing

Recreate the comforting, womb-like 85 dB acoustic environment

Inside the womb, babies are surrounded by a continuous rush of blood flow and maternal heartbeat that reaches up to 85 dB. Soft brown and pink noise replicate this comforting womb atmosphere, calming crying spells and facilitating smoother REM sleep transitions.

Formula: Warm brown noise placed at least 6 feet from the crib at safe moderate volume.
Helps over 80% of newborns fall asleep within 5 minutes
Apply Infant Sleep Settings
Instant Soundscapes

One-Click Circadian Sound Presets

Launch custom tailored frequency profiles optimized for distinct tasks.

Sleep8 Hours

Deep Ocean Sleep

Base: Brown Noise

Heavy low-end rumble with rolled-off highs to simulate dark midnight surf.

Launch Preset
ADHD / Focus90 Minutes

Focus Flow State

Base: Pink Noise

Natural 1/f slope providing balanced stimulation for hours of uninterrupted coding.

Launch Preset
TravelContinuous

Airplane Cabin

Base: Brown + Low Cut

Even cabin pressure drone that isolates you from chatting passengers.

Launch Preset
Relief45 Minutes

Tinnitus Softener

Base: Violet + Grey Noise

Specially shaped high-register hiss to gently blend out ear ringing.

Launch Preset
Calm30 Minutes

Forest Wind

Base: Green Noise

Organic mid-range frequencies reminiscent of wind coursing through pines.

Launch Preset
Privacy2 Hours

Speech Shield

Base: White Noise + EQ

Calibrated speech-band masking for studying in busy coffee shops.

Launch Preset
How We Compare

Synthesized In-Browser vs YouTube & Mobile Apps

See why audio professionals and deep sleepers choose RelaxEnd.

Acoustic FeatureRelaxEnd SynthesizerYouTube / Spotify StreamsPaid Mobile Apps
Audio Generation Method
Real-time 32-bit procedural Web Audio
Pre-recorded compressed video stream
∼Short looped MP3 files
Loop Artifacts & Gaps
Never (Infinite continuous calculation)
Jarring loop breaks or video restarts
∼Audible click every 5–15 minutes
Equalizer & Sound Sculpting
Full 10-band studio EQ (31Hz - 16kHz)
None (Fixed pre-baked audio)
∼Limited or locked behind paywall
Data & Battery Consumption
Negligible (<1 MB initial load, runs on chip)
Massive (Gigabytes of HD video data)
∼High (Background background services)
Advertisements
100% Free & Zero Ads Forever
Loud midnight ads between videos
∼Subscription popups & banner ads
Account or Installation Required
None (Open browser & press play)
Browser or app with tracking
∼App Store install + account signup
Source code
Open-source Web Audio engine
Closed platform
∼Closed source
FAQ

Frequently Asked Questions About Noise Generators

Everything you need to know about sound masking, frequency colors, and our online generator.

Q1

What is an online noise generator?

An online noise generator is a web-based audio synthesizer that generates acoustic signals across various frequencies in real time using your browser's Web Audio API. Unlike playing a pre-recorded YouTube video or Spotify track, RelaxEnd calculates random sound samples mathematically on the fly, creating an infinite, non-repeating soundscape without file downloads or streaming bandwidth.
Q2

What is the difference between white noise, pink noise, and brown noise?

The difference lies in how sound energy is distributed across the frequency spectrum. White noise has equal energy per hertz across all audible frequencies, resulting in a crisp, bright hiss (like television static). Pink noise has equal energy per octave, decreasing by 3 decibels per octave as frequency doubles, creating a softer, rain-like sound. Brown noise drops by 6 decibels per octave, giving it a deep, heavy low-frequency rumble reminiscent of a distant waterfall or heavy surf.
Q3

Why is brown noise so popular for ADHD and focus?

According to the Moderate Brain Arousal (MBA) model and stochastic resonance theory, people with ADHD often have lower baseline dopamine levels in the prefrontal cortex. Smooth, low-frequency stochastic sound like brown noise acts as moderate acoustic stimulation that settles hyperactive internal thoughts, satisfies subconscious sensory cravings, and allows executive attention to stay focused on complex tasks.
Q4

Can a noise generator help with tinnitus?

Yes. Tinnitus is often perceived as an internal high-pitch ringing, buzzing, or hiss that becomes most noticeable in quiet environments when the auditory cortex amplifies faint internal signals. By introducing calibrated background sound, such as grey, pink, or custom-equalized violet noise, the contrast between the tinnitus and silence is reduced. This sound masking facilitates habituation, helping your brain push the ringing into the background.
Q5

Is it safe to listen to noise all night while sleeping?

Yes, provided you keep the volume at a safe level. Audiologists recommend keeping ambient sleep noise below 60 to 65 decibels (roughly the volume of a quiet conversation or gentle shower). RelaxEnd includes a circadian sleep timer with an exponential fade-out feature, allowing the sound to gradually taper off after you have fallen asleep so your ears rest throughout the night.
Q6

Does this noise generator work on mobile phones and tablets?

Yes. RelaxEnd is fully responsive and optimized for modern iOS (Safari, Chrome) and Android browsers. The procedural audio engine runs efficiently in the background while your screen is locked or while you switch between other apps.
Q7

Does it work without an internet connection (offline)?

Yes. Because RelaxEnd generates audio directly on your device using JavaScript and the Web Audio API rather than streaming audio files from a server, once the web page is loaded in your browser tab, the audio engine continues running even if you disconnect from Wi-Fi or switch to airplane mode.
Q8

How does the 10-band equalizer work?

RelaxEnd includes a professional 10-band graphic equalizer spanning from 31 Hz (sub-bass rumble) up to 16 kHz (sparkling high treble). You can boost or cut specific frequency bands by up to ±12 dB to compensate for bass-heavy headphones, reduce piercing high frequencies, or target specific tinnitus frequencies.
Q9

Why is RelaxEnd completely free with zero ads?

Procedural sound synthesis requires virtually zero server bandwidth because the audio computation happens directly on your device's processor. This allows us to offer an uncluttered, high-performance tool without forcing annoying audio ads or subscription walls between you and restful sound.
Q10

Do I need headphones to use the noise generator?

No, you can play noise through your laptop, phone, or desktop speakers to mask room noise or soothe a sleeping baby. However, for deep study focus, personal privacy, or binaural beat tone layering, high-quality over-ear headphones or earbuds provide the most immersive and accurate frequency response.
Q11

Is the RelaxEnd noise engine open source?

Yes. The synthesizer that generates the noise runs in the browser with the Web Audio API. The code is on GitHub. Star the repo if you use it.
Q12

Can I generate any noise color in the browser?

Yes. White, pink, brown, green, grey, blue, and violet are built on the device, not streamed as loops. Open the generator and pick a color.
Open source · No ads · No download

Ready to Tune Out the World?

Open the RelaxEnd noise generator. Pick a noise color, set the equalizer and sleep timer. If the engine helps, star it on GitHub.

Launch Free Noise Generator

The noise engine is open source. Star it on GitHub.