Sleep Sound Generator

Sleep mix

{{ normalizedSleepMin }} min timer Timer off

Vol {{ effectiveVolumePercent }}% {{ activeColorLabel }} Timer {{ normalizedSleepMin }} min Fade {{ fade_in_s }} / {{ fade_out_s }} s

Sound recipe:

Start with pink or brown for softer bedtime masking; use blue focus for alert listening.

Loudness: {{ master_volume_percent }}%

Start low; 0 mutes and 100 is the maximum slider level.

Safe-volume mode:

When on, effective loudness is capped at 45% even if the slider is higher.

Sleep timer:

Enter minutes, use a preset, or drag the 0-120 minute slider; 0 keeps playback continuous until you pause or stop.

min

Fade in / out:

Enter seconds for fade-in and fade-out; decimals such as 2.5 are accepted.

s in

s out

Stereo width: {{ stereo_width_percent }}%

0 keeps the bed centered; 100 uses the widest generated stereo field.

Low cut:

Accepted range: 20-1000 Hz; raise it to thin out low-end rumble.

High cut:

Accepted range: 500-20000 Hz; lower it to soften bright noise.

Movement rate:

Accepted range: 0-2 Hz; slower rates keep the sound steadier.

Movement depth: {{ movement_depth_percent }}%

0 disables movement; 100 creates the strongest sweep.

Hum notch:

Choose Off, 50 Hz, or 60 Hz based on the hum you hear.

Pause when tab hidden:

Keep on unless you intentionally want playback to continue after switching tabs.

Spectrum smoothing: {{ Number(spectrum_smoothing).toFixed(2) }}

Accepted range: 0.00-0.99; higher values make chart motion steadier.

Field	Value	Copy
{{ row.label }}	{{ row.value }}

Priority	Check	Recommendation	Copy
{{ row.priority }}	{{ row.check }}	{{ row.recommendation }}

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Sleep masking uses a steady background sound to reduce the contrast between a quiet room and sudden interruptions. A door click, traffic pass, pipe knock, hallway voice, or fan change can feel sharper when it breaks through silence. A low, steady masking bed can make those changes less abrupt.

Noise color describes how the sound is balanced across frequency. White noise feels bright and broad, pink noise is usually smoother, brown noise leans deeper, and blue noise emphasizes upper bands. Rain, ocean, and fan recipes are practical variations that combine a base color with filtering and slow movement.

Noise color shaped by filters and motion before loudness capping and fade timing

Volume and duration matter as much as the recipe. A percentage slider is not a sound-pressure measurement, because actual exposure depends on speakers, headphones, distance, room acoustics, and personal sensitivity. A comfortable masking sound should stay low enough that it does not pull attention back to itself.

Continuous noise is not a sleep treatment. Research on sound machines and colored noise is mixed, and a sound that helps one person settle may bother another person's sleep. Persistent insomnia, tinnitus distress, or hearing concerns deserve professional advice.

How to Use This Tool:

Pick a recipe first, keep loudness conservative, then shape the sound only as much as the room requires.

Choose Sound recipe. Start with Pink drift or Brown hush for bedtime masking, and reserve Blue focus for wakeful listening.
Set Loudness low and leave Safe-volume mode on unless you have a specific reason to hear the uncapped level. The summary shows Vol based on the effective loudness.
Set Sleep timer with the minutes field, slider, or preset buttons, then choose Fade in / out. A timed session with a longer fade-out usually feels less abrupt than stopping the sound sharply.
Use Play, Pause, and Stop from the live surface. Settings are locked while playback is active, so pause before reshaping the recipe or timer. If the page reports that audio is unavailable, try a different browser or device audio setting.
Open Advanced only when needed. Low cut removes rumble, High cut softens hiss, Hum notch targets 50 or 60 Hz mains hum, and Pause when tab hidden helps prevent surprise background playback.
Review Session Metrics, Coach Notes, Masking Spectrum Blueprint, and Wind-down Envelope after changing settings. If coach notes warn about high level, no timer, short fade-out, or a bright recipe, correct those before a long session.

Interpreting Results:

Effective loudness is the value that matters for the generated output because safe-volume mode can cap the slider at 45 percent. It is still a relative browser level, not a decibel reading. Keep the real listening level comfortable and lower it if speech, alarms, or body cues become harder to notice.

Base noise color and Recipe intent explain the rough listening character before filters are applied.
Filter range shows the low and high cutoff points. Raising the low cut thins rumble; lowering the high cut reduces brightness.
Movement LFO reports the slow filter motion. More depth and rate can make rain or ocean recipes feel active, but too much movement can become distracting.
Coach Notes separates warnings and setup advice from the raw metrics so loudness, timer, fade, and recipe checks can be copied or exported on their own.
Wind-down Envelope shows how the session splits across fade-in, steady playback, and fade-out. A good chart shape is not proof that the level is suitable for your ears.

Technical Details:

Colored noise differs by spectral balance. White noise is the brightest reference because it does not intentionally reduce high-frequency energy. Pink noise tilts downward as frequency rises, brown noise tilts even more toward lower frequencies, and blue noise emphasizes the upper range. The recipes combine those base colors with filter cutoffs, stereo width, slow movement, timer state, and gain scaling.

The sound-shaping path starts with random samples, then applies a high-pass cutoff, a low-pass cutoff, an optional hum notch, stereo spread, and output gain. A slow oscillator can move the low-pass cutoff, which makes some recipes feel less static without turning the sound into melody or speech.

Formula Core:

The loudness slider is converted to effective loudness, then squared as a fraction to produce the target gain. Squaring gives finer control near the quiet end.

G_{target} = {(\frac{V_{effective}}{100})}^{2}

With safe-volume mode on, a 52 percent slider becomes 45 percent effective loudness, so the target gain is 0.45 x 0.45 = 0.2025. A 32 percent effective setting produces 0.1024. These are gain values inside the playback chain, not calibrated acoustic exposure values.

Sleep sound recipe families and technical behavior
Recipe or Control	Technical Role	Useful Check
`Pink drift`	Pink base with moderate low and high cutoffs.	Good first pass for general bedtime masking.
`Brown hush`	Brown base with deeper low-frequency body.	Useful for distant rumble, but keep level low.
`White mask`	White base with broader high-frequency coverage.	Lower `High cut` if hiss feels sharp.
`Focus blue`	Blue upper-band emphasis.	Better for alert listening than sleep onset.
`Hum notch`	Narrow cut at 50 or 60 Hz.	Use only when mains hum is actually present.

Timer math divides a session into fade-in, steady bed, and fade-out slices. If the timer is off, the envelope chart uses a 60 minute projection so the fade-in and steady-bed shape can still be inspected.

Limitations:

The generated level is not calibrated in dBA, and safe-volume mode is a conservative gain cap rather than a hearing-safety guarantee. Device hardware, headphones, room acoustics, and duration decide the real exposure.

Use the lowest comfortable level, especially for headphones and long sessions.
Stop using the sound if it causes discomfort, ringing, headache, anxiety, or worse sleep.
Keep environmental safety in mind. Masking should not hide alarms, children, medical devices, or other signals you need to hear.

Worked Examples:

A light sleeper near a hallway starts with Pink drift, Safe-volume mode on, Loudness at 28 percent, a 45 minute Sleep timer, and a 45 second fade-out. Session Metrics shows effective loudness under the cap, and the coach note stays balanced.

A room with low HVAC rumble uses Brown hush, Low cut around 45 Hz, High cut near 4200 Hz, and modest movement. If the sound feels heavy, raising Low cut thins the rumble before loudness is increased.

A bright white-noise setup with White mask, High cut above 8500 Hz, no timer, and safe-volume mode off can draw warnings. Lower the high cut, turn the cap back on, and set a 30 to 90 minute timer before treating it as a bedtime preset.

FAQ:

Is the safe-volume cap a medical safety limit?

No. It caps the effective browser gain at 45 percent, but it cannot know your headphones, speakers, distance, or room level. Use your ears, keep the level low, and measure real sound level when exposure matters.

Why does blue focus warn against bedtime use?

Blue focus emphasizes upper bands, which can feel sharper and more alerting. For sleep onset, start with Pink drift, Brown hush, Rain veil, or Ocean roll.

What should I change if the sound feels harsh?

Lower Loudness, keep Safe-volume mode on, reduce High cut, or switch away from White mask and Blue focus. Adjust one control at a time so the result is easy to judge.

Does the generator upload audio?

No. The sound is generated for playback in the current browser session. Exported metrics and charts describe the selected settings, not an uploaded audio recording.

Glossary:

White noise: Broad random noise with a bright, even character.
Pink noise: Noise that reduces energy as frequency rises, often heard as smoother than white noise.
Brown noise: Noise with stronger low-frequency weight and less high-frequency brightness.
High cut: A filter setting that reduces upper-frequency content above the selected point.
Fade-out: The timed reduction in gain before the session ends.

References:

Noise-Induced Hearing Loss, CDC/NIOSH.
Hearing Protectors, National Institute on Deafness and Other Communication Disorders.
Noise, World Health Organization Regional Office for Europe.
Systematic review: auditory stimulation and sleep, Weill Cornell Medicine, 2021.