White noise
ProEndless Static Drift
Equal energy across every frequency, like a detuned radio or a strong fan. The classic choice for covering voices, traffic and sudden noises.
- Open-plan offices
- Noisy neighbours
- Short focus sprints
Noise colors
15 noise colors, from white to violet
White, brown, pink, green, grey, blue and violet noise, plus warm and bright textures you won't find elsewhere.
Noise colors describe where a noise's energy sits. White noise has equal energy at every frequency and sounds like static; pink and brown noise put more energy in the low end and sound like rain or a deep rumble; blue and violet noise are bright and crisp. Solbox has 15 noise colors and textures, and brown noise is free.
Free on iPhone · iOS 17.6 or later
Every noise in Solbox
Start with the table, then try each one for a full work block.
| Noise | Character | Good for |
|---|---|---|
| White noise | Even, bright | Open-plan offices, Noisy neighbours, Short focus sprints |
| Brown noise | Deep, low | Long deep-work sessions, Falling asleep, Quieting a busy mind |
| Pink noise | Warm | Studying, Reading, Night-time listening |
| Green noise | Balanced | Gentle focus, Calm evenings, Background for reading |
| Grey noise | Balanced | Steady concentration, Masking office chatter, Sensitive ears |
| Blue noise | Bright, crisp | Waking up, Quick tasks, Cutting through low hum |
| Violet noise | Bright, crisp | Energetic work blocks, Short sprints, Creative sessions |
Noise colors
Brown noise
FreeEarth Rumble Below
Most of the energy sits in the low end, so it sounds like a deep rumble, distant surf or a waterfall heard from inside. Softer on the ears than white noise, which is why many people with ADHD keep it on for hours.
- Long deep-work sessions
- Falling asleep
- Quieting a busy mind
Pink noise
ProRosy Horizon Hum
Energy drops off evenly as the pitch rises, so it sounds like steady rain or wind in leaves. A gentle middle ground between white and brown.
- Studying
- Reading
- Night-time listening
Green noise
ProBalanced Horizon Flow
Centered on the middle frequencies, a little like the hum of a forest or a soft waterfall. Natural-sounding and easy to forget it's on.
- Gentle focus
- Calm evenings
- Background for reading
Grey noise
ProUrban Neutral Pulse
Shaped to sound equally loud at every pitch to the human ear. An even, neutral hiss that many people find less sharp than white noise.
- Steady concentration
- Masking office chatter
- Sensitive ears
Blue noise
FreeAzure Clarity Spark
Tilted toward the high frequencies, so it sounds crisp and bright, like a fine spray of water. Short, alert sessions suit it best.
- Waking up
- Quick tasks
- Cutting through low hum
Violet noise
ProViolet Edge Surge
Even brighter than blue noise, with most of its energy at the very top. A sharp, airy hiss for short bursts of work.
- Energetic work blocks
- Short sprints
- Creative sessions
Solbox textures
Mid-warm noise
ProAmber Drift
A Solbox blend of low rumble and smooth midrange. Warmer than pink noise and lighter than brown.
- Winding down
- Calm focus
- Adding depth to a mix
Velvet noise
ProVelvet Noise
A smooth, warm midrange texture with no sharp edges. Sits quietly under music or speech.
- Background use
- Mixing with other apps
- Long sessions
Deep ground noise
ProEarth Hum
An even deeper low-end rumble than brown noise. Heavy, rooted and very easy to sleep to.
- Sleep
- Grounding
- Masking low traffic
Bright focus texture
ProSilver Static
A crisp high-frequency texture that cuts through distractions without the harshness of plain white noise.
- Deep focus
- Noise masking
- Busy cafés
High shimmer texture
ProCrystal Wash
A shimmering high-frequency noise with a gentle pulse. Light and bright rather than heavy.
- Light energy
- Creative work
- Daytime sessions
Rhythmic noise texture
ProQuartz Pulse
A finely textured noise with a slow rhythmic swell and a little high-end shimmer, so it never feels static.
- Flow sessions
- People who find flat noise boring
- Repetitive tasks
Flowing low-mid texture
ProIron Wind
A soft dual-tone wave in the low-mid range. Best with headphones.
- Meditation
- Deep focus
- Quiet introspection
Binaural focus tone
ProTheta Sync
A 200 Hz base tone with a 7 Hz difference between the ears, designed to layer under any other sound. Needs headphones.
- Layering under noise
- Meditation
- Slow evenings
What does the color of a noise mean?
A noise “color” is a shorthand for its spectrum, the way its energy is spread from low to high frequencies. The names borrow from light: white light contains every color equally, and white noise contains every frequency equally.
- White noise: equal energy at every frequency. Bright, hissy, like a detuned radio.
- Pink noise: energy falls by half with every octave. Sounds like steady rain.
- Brown noise: energy falls even faster, so it is mostly low end. Sounds like a deep rumble.
- Green noise: focused on the middle frequencies. Natural and soft.
- Grey noise: shaped so every pitch sounds equally loud to human ears.
- Blue and violet noise: tilted toward the high frequencies. Crisp and airy.
Which noise color is best for focus?
There is no single winner. A 2024 meta-analysis of 13 studies found that white and pink noise gave a small benefit on task performance in children and young people with ADHD, though results varied from person to person and the studies were small. Brown noise has become hugely popular in ADHD communities even though it has barely been studied.
The practical answer: try each color for one full Pomodoro block. The right one is the one you stop noticing.
- If you want the strongest masking of voices, try white or grey.
- If white feels harsh, try pink or green.
- If you want something deep and heavy, try brown or Earth Hum.
Noise colors for sleep
At night most people reach for deeper noise, such as pink, brown or Earth Hum, mixed with soft rain or distant thunder. Set a sleep timer so the sound fades out instead of stopping suddenly. For a side-by-side comparison, read white vs pink vs brown noise.
What are Solbox textures?
Beyond the classic colors, Solbox has eight textures designed for long sessions, like Amber Drift (between pink and brown), Velvet Noise (smooth midrange), Silver Static (a crisp focus texture) and Quartz Pulse, which has a slow rhythmic swell for people who find flat noise boring. Theta Sync is a binaural tone meant to layer under other sounds.
How to use noise in Solbox
Pick a noise from the carousel on the Home screen and tap play. Each noise loops seamlessly, has its own volume, and can be layered with soundscapes or a binaural preset. Brown and blue noise are free; the rest come with Solbox Pro.
Noise colors: common questions
What is the difference between white, pink and brown noise?
White noise has equal energy at all frequencies, so it sounds bright and hissy. Pink noise loses energy as the pitch rises and sounds like steady rain. Brown noise drops off even faster and sounds like a deep rumble or distant surf.
Why do people with ADHD like brown noise?
Many people with ADHD describe brown noise as calming and say it quiets their inner chatter. Research on brown noise specifically is still very limited, so the honest advice is to try it and see whether it works for you.
What is green noise?
Green noise concentrates its energy in the middle frequencies, around where nature sounds sit. It sounds softer and more natural than white noise, a little like a forest or a distant waterfall.
Is it safe to listen to noise all day?
Keep the volume low, around the level of a quiet conversation, and take breaks. Background noise should be easy to forget, and loud sound over long periods can harm your hearing.