What are the colors of noise?

Generally speaking, when we talk about various types of random signals or noise, we’re talking about their spectral properties. White noise has a flat spectral distribution and equal power across all frequencies, whereas other colors of noise have more power at some frequencies or less power at others. The various colors of noise are called after the colors of the visible light spectrum.

The different colors of noise can have various applications, such as testing and calibrating audio equipment, creating soothing sounds for relaxation or sleep, masking distracting sounds in a noisy environment, or digital signal processing and computer graphics

The majority of people will identify these as a sound that promotes sleep. Beyond their potential to promote rest and sleep, some colors have also been linked to benefits for concentration and neurodivergent circles. This is because certain tones of sound alter the fundamental mental condition of the listener.

This blog will introduce you main 3 types of colors of noise and after you finish reading this, I hope you can find the color that you might prefer or suit your need.

White noise

We’ll start with white noise, which most people are at least somewhat familiar with, to better understand the different types of noise. White noise includes all audible sound frequencies in equal amounts, just as the color white is composed of all the colors in the rainbow. It is a high-pitched sound that is frequently likened to static or, less frequently, to a hissing sound.

White noise is a statistical model for noise in acoustical engineering, statistics, physics, and telecommunications. It is most often used to lessen the effects of ambient noise via the use of a fan or white noise machine. This is also helpful when someone can’t sleep because it is too quiet. It has been useful in quieting crying babies, improving concentration, and may help control symptoms of ADHD Moreover, White noise has been shown to reduce babies’ crying, help them sleep longer, and reduce pain during infant vaccination. However, research shows that not everyone gains a benefit. Some people find white noise distracting and may suffer decreased cognition and neurological health.

According to Göran Söderlund, a special education professor in Sweden who studies neuroscience and cognition, there is a popular theory called stochastic resonance. This theory suggests that the presence of white noise can help the brain tune into hard-to-hear tones, such as music, people’s voices, or ambient sounds, that might otherwise go unnoticed. Essentially, by turning on white noise, other stimuli can become clearer and more easily focused upon.

Dr. Diaz explains that both internal and external cues can distract the brain. For example, worrying about whether you turned off the curling iron can become overwhelming. However, noise that is just stimulating enough to activate the brain without overwhelming it can help drown out some of the internal chatter and mask background noise.

An example of white noise:  the static sound you might hear on an analog television or radio when there is no signal being received, radio static, and the sound of a fan, Humming airconditioner

White noise
Example-Fan

Pink noise

Pink noise is a form of random noise that shares similarities with white noise, but with a unique spectral distribution. Unlike white noise, which has equal power across all frequencies, pink noise has more power at lower frequencies, creating a deeper, more calming sound. The term “pink” refers to the color pink’s relationship to the frequency spectrum. It is also known as “1/f noise” because the power in the frequency spectrum decreases as the frequency increases, following a mathematical relationship known as a power law. This produces a lower-pitched sound that is smoother and more pleasant to the ear than white noise, making it an ideal choice for use as a sleep sound.

In terms of sleep quality, pink noise has been found to increase the amount of time spent in slow-wave sleep, which is the deep, restorative stage of sleep that is important for physical and mental recovery.  Pink noise is common in biological systems and it is also called ambiance noise, it filters out things that distract you, like people talking or cars going by, so they don’t interrupt your sleep. The sounds of the human heartbeat, rain, wind, the sound of a waterfall, rustling leaves, or the seashore are examples of pink noise that can help promote relaxation and improve sleep quality. Pink noise has also been shown to improve memory consolidation, meaning the process by which the brain strengthens newly formed memories during sleep. Furthermore, some studies have suggested that pink noise may improve cognitive function and attention, especially in older adults

Pink noise is frequently employed as a background or control noise because studies have shown that it is less disruptive than other types of noise. In fact, research suggests that exposure to pink noise can be calming and stress-reducing. For instance, a study revealed that individuals who listened to pink noise while in an intensive care unit experienced less stress than those exposed to typical ICU sounds.

Examples of pink noise:  The sounds of the human heartbeat, rain, wind, the sound of waterfall, rustling leaves, or the seashore

Pink Noise
Example-Rain

Brown noise

Brown noise, also called red noise. The name “brown noise” is actually derived from the color “brown” in the context of noise colors, which are named based on their similarity to the light of different colors. However, the origins of the concept of brown noise are related to Robert Brown, a Scottish botanist who discovered “Brownian motion” – the erratic movement of small particles suspended in a fluid. Experts suggest that the term “brown noise” was coined to describe this type of noise due to its resemblance to Brownian motion. Brown noise is produced by generating sound signals that change randomly from one moment to the next, creating a static-like sound.

Distance thunder-deep, rumbling sound

Brown noise is a type of random noise that has a spectral distribution that is similar to pink noise, but with more power at even lower frequencies. Unlike pink noise, which has a more uniform distribution of energy across the frequency spectrum, brown noise has a more pronounced decrease in energy as the frequency increases. This results in a deep, rumbling sound that some people find relaxing.

Brown noise is known to induce relaxation due to its similarity to the brain’s resting state. Its lower frequencies produce a deep and gentle sound that is often found soothing by many individuals. Some people even curate brown noise playlists specifically for babies, as it’s believed to replicate the calming sound environment inside a mother’s womb.

In addition to its relaxation benefits, auditory noise may have the potential for improving cognitive function. Some small studies have suggested that noise can enhance memory in children with ADHD. Andrew Kahn, PsyD, who serves as the associate director of behavior change and expertise at Understood, refers to the Moderate Brain Arousal model (MBA), which proposes that dopamine levels regulate the amount of noise needed for optimal cognitive performance. According to this theory, individuals with learning differences such as ADHD have lower levels of internal stimuli or noise in their brains.

Moreover, it has been some research that brown noise can also soothe conditions like tinnitus, or ringing in the ears, in certain individuals. Whereas the high frequencies of white noise exacerbated symptoms, brown noise helped to mask them.

Examples of Brown noise: rainfall, distant thunder, strong win, ocean wave

Brown noise
Example-Ocean wave

People with anxiety tend to be on high alert… The use of pink or brown noise may reduce their reactivity to those little sounds in their environment and support calming, sleep, or even concentration.

— ANDREW KAHN, PSYD

The difference between White, Pink, and Brown noise

White

sounds staticky. White noise combines sounds of every audible frequency in the same way that white light emanates all pigments of visible light with the same intensity. Compared to brown noise, it sounds more fizzling.

Pink

is a sanded-down version of white noise, playing lower frequencies a bit louder. It sounds like gentle rainfall, or the light sputter of a sprinkler, with less hissing than white noise.

Brown

includes all frequencies, similar to white noise, but emphasizes the low frequencies more and mutes the high frequencies.

While white noise is commonly used for masking unwanted sounds and promoting concentration, pink and brown noise are often used for relaxation, meditation, and sleep. Pink noise is generally considered less harsh and more pleasant to the ear than white noise, while brown noise is even deeper and more rumbling. However, individual preferences for noise type may vary.

In summary, Each type of noise can be used for different purposes, such as improving sleep, increasing focus, or reducing stress, and it can combine together to create the new noise or ambience that the creator prefers. Overall, understanding the differences between these types of noise can help individuals choose the best sound for their specific needs.