Sleep Sounds — White, Pink, Brown
Sleep sounds with continuous white, pink and brown noise plus 15–60 minute timers and gentle fade-out. Mask night noise. Free in your browser, no download.
Protect your hearing. Start at a low volume. Never raise the volume to make a tone audible. Levels are shown in dBFS, relative to full scale — not SPL.
How it works
White, pink, and brown noise is synthesized live in your browser using an AudioWorklet without looping or streaming. The sleep timer employs sample-accurate hardware AudioParam automation to execute a 30-second gentle fade-out down to complete silence.
Sleep sounds provide a steady, soothing acoustic blanket that masks disruptive ambient noise and eases an overactive mind into restful sleep. Rather than relying on looped MP3 files with jarring repeating clicks, this generator synthesizes pure white, pink, and brown noise in real time directly inside your browser using the Web Audio API.
The Acoustics of Sleep Noise: Auditory Masking
When you sleep, your ears never turn off. The brain continues to monitor acoustic inputs for threats or changes. The primary reason sudden noises—such as a slamming car door, a barking dog, or floorboard creaks—wake you up is not necessarily their absolute loudness, but their sudden delta (contrast) against the background quiet.
Acoustic noise raises the ambient noise floor with a smooth, continuous spectrum. By reducing the signal-to-noise ratio of sudden environmental noises, sleep noise prevents them from reaching the threshold required to trigger an arousal in the auditory cortex.
White, Pink, and Brown Noise Compared for Sleep
Different colors of noise shape how acoustic energy is distributed across the audible spectrum:
1. White Noise (0 dB/octave · Bright Masking)
White noise contains equal acoustic energy per Hertz across the entire audible spectrum (20 Hz – 20,000 Hz). Because human hearing is logarithmic, white noise is perceived as a crisp, bright hiss (similar to TV static or rushing air). It provides the most comprehensive masking against high-frequency disruptions, street chatter, and sirens.
2. Pink Noise (-3 dB/octave · Slow-Wave Sleep Enhancer)
Pink noise drops 3 dB in energy per octave, providing equal acoustic energy per octave band. This matches human hearing sensitivity much more naturally, sounding like steady rain or ocean wind. Multiple clinical sleep studies have demonstrated that synchronous pink noise stimulation enhances slow-wave (delta) brain activity during deep sleep and aids memory consolidation.
3. Brown Noise (-6 dB/octave · Deep Velvet Warmth)
Brown noise (Brownian or red noise) drops 6 dB per octave, concentrating the majority of its acoustic energy in the deep low frequencies below 500 Hz. It sounds like a powerful waterfall, a heavy thunderstorm, or the steady hum of an airplane cabin. It is widely praised by individuals with ADHD, anxiety, or racing thoughts because the absence of harsh high frequencies provides profound cognitive calm.
Gentle Fade-Out Protection
Standard sleep timers often create a secondary problem: when the timer expires, the sudden silence triggers an acoustic awakening.
This tool incorporates a dedicated 30-second gradual fade-out curve into every 15, 30, and 60-minute timer. As your chosen duration nears completion, the Web Audio hardware gain gently descends along a smooth ease curve down to complete silence, ensuring seamless continuity as you drift into deeper sleep stages.
Safe Listening Recommendations
To protect your hearing while enjoying restorative sleep:
- Keep Volume Below 60 dBA: Position speakers several feet away from your head at a moderate level where speech would easily be heard over the noise.
- Avoid Sleeping in High-Volume Headphones: If wearing sleep earbuds or headbands, keep the volume slider in the lower green zone.
- Use Night Mode: Tap Bedside Night View to dim your screen into an ultra-dark bedside clock view, preventing blue light from interfering with your brain’s natural melatonin production.
Frequently asked questions
Which noise color is best for falling asleep?
It depends on your bedroom acoustic environment and personal sensitivity. Pink noise has equal energy per octave (-3 dB/octave) and closely mimics rainfall or rustling leaves; clinical sleep studies associate it with improved slow-wave deep sleep and memory consolidation. Brown noise has an even steeper roll-off (-6 dB/octave) resulting in a warm, velvety rumble similar to a waterfall or distant jet cabin, which many people with ADHD or racing thoughts prefer. White noise has equal energy across all frequencies and is best for masking sharp, erratic sudden sounds like traffic horns, loud neighbors, or barking dogs.
Why is the timer fade-out important for sleep?
Human hearing remains vigilant during sleep. The brain's auditory cortex continues to process ambient sound and monitors for sudden environmental changes. If a sleep sound abruptly cuts out after 30 or 60 minutes, the sudden transition to silence triggers an acoustic startle response and micro-arousal that can wake you up. Our sleep sounds tool includes an automatic 30-second smooth fade-out at the end of every timed session, gently lowering volume to zero without disturbing your sleep cycle.
Is it safe to play noise all night while sleeping?
Yes, provided the volume is kept at a safe, moderate listening level. The American Academy of Pediatrics and audiology guidelines recommend keeping sleep sound machines below 60 dBA at the sleeper's ear level (roughly conversational speech volume or quieter). Avoid high volumes, especially when using headphones or earbuds in bed, to prevent auditory fatigue and protect your hearing.
Does this tool require an internet connection or audio streaming?
No. All sound is synthesized live in real time directly within your web browser using the Web Audio API and an AudioWorklet. No audio files are streamed, nothing is tracked or recorded, and audio playback continues seamlessly even if your device goes offline. You can also download a seamless offline WAV loop for air travel or offline sound players.
What does the Bedtime Warmth Filter do?
The Bedtime Warmth Filter applies a gentle low-pass filter rolling off high frequencies above 3.5 kHz. This eliminates harsh upper-frequency hiss from white or pink noise, creating a softer, warmer, womb-like acoustic texture that is particularly soothing for sensitive ears.
What is the best noise for sleep?
Pink noise suits most sleepers because its equal energy per octave mimics rain and stays gentle on the ears. Brown noise feels deeper and helps when traffic or voices break through, while white noise masks sharp sudden sounds best. Keep volume moderate, set a timer with fade-out, and switch colors if you wake mid-cycle.