Colour Noise Generator

The Science of Colour Noise

Just as white light contains all colours of the visible spectrum, white noise contains all audible sound frequencies. Scientists categorise noise by colour based on how energy is distributed across the frequency spectrum. The names are borrowed from optics: white noise is the sonic equivalent of white light, while pink and brown noise shift energy toward lower frequencies, much as filtering white light through a warm filter shifts it toward red.

Different colour profiles affect the brain differently. The frequency distribution determines whether a noise sounds harsh or smooth, stimulating or soothing, and this is why some people sleep better with pink noise while others focus better with brown. Understanding what each colour actually is, and what it does to neural processing, lets you choose the right one for your situation rather than guessing.

White Noise

White noise has equal energy at every frequency from 20Hz to 20,000Hz. It is the sound of pure statistical randomness: every frequency is present at the same power, producing the familiar hissing or static sound. This is the noise colour most people recognise and the one most commonly built into commercial sound machines.

White noise works primarily as a sound mask. By producing a consistent blanket of sound across the entire audible spectrum, it reduces the contrast between background silence and sudden noises like traffic, doors, or a partner snoring. The brain habituates to the constant stimulus and stops alerting to small environmental changes. This is why it is so effective in noisy environments: it does not eliminate the interrupting sounds, it makes them less noticeable by raising the baseline.

White noise is the most commonly studied noise colour for infant sleep. A frequently cited study by Spencer, Moran, Lee, and Talbert found that white noise helped 80% of newborns fall asleep within five minutes, compared to 25% without it. For adults, white noise is most useful in noisy bedrooms, open-plan offices, or any environment where unpredictable sounds are the main sleep disruptor.

One drawback: because white noise has equal energy per frequency, and the human ear is more sensitive to higher frequencies (the Fletcher-Munson curves), white noise can sound harsh or bright to some listeners. If you find it grating, pink or brown noise may be more comfortable.

Pink Noise

Pink noise reduces energy by 3dB per octave as frequency increases. This means lower frequencies are proportionally louder than higher ones, producing a sound that is warmer and smoother than white noise. It sounds like steady rain on a roof, a gentle waterfall, or wind rustling through leaves. Many natural ambient sounds follow a roughly pink noise distribution, which is why it tends to sound more pleasant and organic than white noise.

Pink noise is the colour with the strongest research backing for adult sleep improvement. A 2012 study published in the Journal of Theoretical Biology by Zhou and colleagues found that pink noise played during sleep enhanced deep slow-wave sleep and significantly improved memory consolidation in older adults. Participants exposed to pink noise during sleep showed a 26% improvement in a word recall test the following morning.

Further research published in Frontiers in Human Neuroscience confirmed that pink noise timed to coincide with slow-wave sleep oscillations increased the amplitude of those oscillations. The mechanism appears to be entrainment: the brain's delta waves during deep sleep naturally follow a roughly 1/f (pink) distribution, and external pink noise may reinforce these patterns rather than competing with them.

Pink noise is often called the Goldilocks noise for sleep. It retains enough high-frequency content to mask environmental sounds (like white noise does), while adding enough low-frequency warmth to feel soothing rather than harsh. For most adults looking for a sleep aid, pink noise is the best starting point.

Brown Noise

Brown noise, also called Brownian noise or red noise, reduces energy by 6dB per octave. It is named not after the colour but after Robert Brown, the botanist who first described Brownian motion, the random movement of particles in a fluid. Mathematically, brown noise is the integral of white noise: each sample is derived from the previous one, creating a random walk through amplitude values. The result is a deep, low-frequency rumble that sounds like a strong waterfall, heavy wind, or the low roar of a distant motorway.

Brown noise has become enormously popular on social media in recent years, particularly on TikTok, where millions of viewers report that it helps with focus, calm, and reducing anxiety. The community most vocal about its benefits is people with ADHD, who frequently describe brown noise as quieting the constant internal chatter that makes concentration difficult.

The scientific evidence specifically for brown noise and ADHD is still limited. Most controlled studies on noise and attention have used white or pink noise. A 2007 study by Soderlund, Sikstrom, and Smart found that white noise improved cognitive performance in children with ADHD, and suggested that the mechanism involves stochastic resonance, the phenomenon where a moderate amount of noise can actually improve signal detection in the brain. Whether brown noise is superior to white or pink for this purpose has not been established in controlled trials.

What is clear is that the subjective experience is real for many people. The deep frequency profile of brown noise may activate the parasympathetic nervous system, promoting a state of physical relaxation that supports sustained attention. The heavier bass also creates a more immersive, enveloping sound field than white or pink noise, which some users describe as feeling like being wrapped in sound.

Other Noise Colours

The spectrum of noise colours extends beyond white, pink, and brown. Blue noise has energy that increases with frequency, the inverse of pink. It sounds bright and hissy and is rarely used for sleep or relaxation. Violet noise increases even more steeply, concentrated almost entirely in the highest frequencies. Grey noise is psychoacoustically flat: unlike white noise, which has equal energy per frequency, grey noise is calibrated to sound equally loud at all frequencies, compensating for the ear's unequal sensitivity curve described by the Fletcher-Munson contours. These colours exist for completeness in audio engineering and acoustics but are far less commonly used for sleep, focus, or relaxation than the three primary colours above.

Which Colour Noise Is Best for Sleep?

The honest answer: it depends on the person. Pink noise has the strongest research backing for enhancing deep sleep and improving memory consolidation. It is the recommended starting point for most adults. Brown noise is preferred by people who find white noise too harsh or who want something more immersive and enveloping. White noise is the most effective pure sound masker and remains the best choice in noisy environments where blocking external sounds is the primary goal.

The best approach is to try each one using the generator above and notice which feels most comfortable. Many people find that a blend works better than any single colour: the Deep Sleep preset (pink 60, brown 40) combines the sleep-enhancing properties of pink noise with the immersive depth of brown. Spend at least five minutes with each colour before deciding, as initial impressions can shift as your brain adjusts to the sound.

Which Colour Noise Is Best for Focus?

White and brown noise are the most commonly reported colours for improving focus and concentration during work or study. White noise provides the strongest masking effect, blocking distracting sounds like conversation or traffic. Brown noise's recent popularity for ADHD focus is significant: while the controlled evidence is still catching up with the anecdotal reports, the mechanism of stochastic resonance provides a plausible explanation for why moderate noise levels can improve cognitive performance in some individuals.

Pink noise may also support focus through its relationship with memory consolidation. If your work requires sustained learning and recall, pink noise in the background may support the encoding process. The Focus preset above (white 50, pink 20) provides a balanced starting point that combines strong masking with subtle pink noise warmth.

Frequently Asked Questions

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

White noise has equal energy across all frequencies. Pink noise has more energy in lower frequencies, decreasing by 3dB per octave, and sounds like steady rain. Brown noise decreases by 6dB per octave and sounds like a deep rumble. Each colour affects sleep and focus differently.

Does brown noise help with ADHD?

Many people with ADHD report that brown noise helps them focus, and the topic has gained huge attention on social media. However, controlled scientific studies specifically testing brown noise for ADHD are limited. Research on white and pink noise in ADHD populations has shown some positive effects on task performance. The subjective benefit is widely reported, even if the specific mechanism is not fully understood.

Is it safe to listen to noise all night?

At moderate volumes (under 50dB, roughly the level of a quiet conversation), ambient noise is generally considered safe for overnight use. Avoid high volumes through earbuds for extended periods. A dedicated speaker at low volume is preferable to headphones for all-night listening.

Why does pink noise help with deep sleep?

Research suggests that pink noise synchronises with brain oscillations during deep (slow-wave) sleep. A study published in Frontiers in Human Neuroscience found that pink noise timed to slow-wave sleep increased the size of slow oscillations and improved memory recall. The low-frequency emphasis may resonate with the brain's natural delta wave patterns during deep sleep.