Did you know that your brain instantly perceives two crucial characteristics of a sound to aid in your understanding of it:
Frequency/Pitch – Is the noise high, like a scream, or low, like a bass?
Amplitude/Intensity — Is the noise loud like a hoover cleaner or quiet like a whisper?
Vibrations that move through the air like a wave create sounds. Air molecules oscillate, which causes molecules nearby to vibrate as well. The sound’s vibrations spread out from the source and become less powerful as they do so. Tiny bones in your ear detect the vibrations when the music reaches you, and your brain handles the remainder of the processing.
Explore these ideas in more detail below, or skip to the section on how sound can put your baby to sleep.

Frequency

The speed at which sound waves vibrate is known as frequency. Hertz (Hz) is the unit of frequency measurement; 1 Hz equals one vibration or one cycle per second. Dogs can hear sounds up to 45000 Hz, but the human ear can only hear sounds between 20 and 20000 Hz.

Pitch describes the frequency of human emotion (high pitch sounds are high frequency, low pitch are low frequency).
Amplitude

The strength or power of the sound waves is their amplitude. Decibels are used to measure amplitude (dB). A loud concert can reach 120 dB, and 160 dB rapidly perforates an eardrum. Typical voices are around 60 dB; anything over 85 dB is regarded as an undesirable level at work.

Amplitude flowing through a specific place, at a specific time, and in a specific direction is described by intensity.

Decibels

Sound intensity is measured in decibels, which are not linear measurements. Since they are measured using a logarithmic scale with a base of 10, they do not increase linearly. This is due to the fact that in order to make a sound twice as loud, its intensity actually needs to be multiplied by roughly 10. The logarithmic measure of decibels and how humans perceive sound are more accurate.

Hence, intensity rises by a factor of 10 for every 10 dB increase in amplitude. When compared to the gap between 60 and 120 dB, the volume differential between 20 and 60 dB is negligible. A average conversation is roughly 60 dB, a hoover cleaner is about 80 dB, and a plane taking off is about 140 dB. Whispering is roughly 20 dB.

Octaves

Octaves talk about frequency doubling. An octave, for instance, might be thought of as the range of frequencies between 20 Hz and 40 Hz or 100 Hz and 200 Hz.

The strange thing is that we don’t interpret the difference between 20 and 40 Hz and 10,000 and 20,000 Hz as being linear. Yet, higher frequency noises are more perceptible to human hearing, which helps to explain how we feel when we hear them, such as wailing babies.

White Noise

The waveforms of the noises you hear every day are often quite brief and have fairly random amplitude and frequency distributions.

When low, mid, and high frequency noises are played concurrently and with the same strength, white noise results.

All the frequencies a human ear can hear (about 20 Hz to 20 kHz), randomly broadcast at the same amplitude, are what is known as white noise. It is sometimes compared to TV or radio static. White noise is a sound wave that is made up of all the frequencies that we can hear, blended together, in the same way that a beam of white light is made up of all the colours.

Pink noise is frequently mischaracterized as white noise.

White noise may not actually be what you perceive it to be. As white noise is made up of all audible frequencies at the same intensity and the human ear is more sensitive to higher frequencies, it may sound unpleasant to some.

Shades of Sound

In an analogy to the distinct colours of light, the various «colours» of sound are determined by their frequency and amplitude.

Some colours have more or less power in the higher or lower frequencies than white noise does in all audible frequencies.

Pink Noise

Compared to white noise, pink noise is less «bright» sounding. All of the audible frequencies are present in pink noise as well, but the intensity of the sound is much more evenly distributed since as the frequency doubles, it decreases in intensity.

More low-frequency tones and fewer high-frequency tones are used to create pink noise. White noise is less unbalanced than it. Due to its equal power per octave, pink noise is frequently seen as being more flat and balanced.

Brown Noise

Brownian motion, a phenomena that describes the random movements of particles, was discovered by Robert Brown, who is also the name of the phenomenon that gives rise to brown noise. Brown(ian) noise most nearly mimics the «colour» of red sound. Pink noise and red noise are comparable, but red noise is more intense at low frequencies.

Much more low frequency tones are present in brown noise (sometimes called red noise) than in pink noise. More profound than pink noise

Energy decreases in pink noise by around 1-3 dB each octave and in red noise by about 6 dB per octave. Red noise is frequently interpreted by listeners as a deeper, roaring or rumbling sound.

Natural Noises

Pink noise is frequently connected to rain or wind, white noise with television or radio static, and brown or red noise with thunder or a far-off waterfall. Audio engineers can produce all of these sounds, but they can also be found naturally in our surroundings.

Depending on how much emphasis is placed on high and low frequencies, rain, wind, waves, thunder, and noises from artificial objects like tvs, vacuums, fans, and many more, can all be instances of these many colours of sound. When capturing natural sounds, the engineer must make sure that the noises are as close to covering the entire spectrum of frequencies as possible. The intensities of the sounds can then be changed to produce any of the many different tones of sound.

Rest of the Rainbow

The most well-known colour of sound is white noise, which plays all frequencies at the same volume.

The emphasis on pink and red/brown noise is on lower frequencies.
The emphasis of blue and violet noise is on higher frequencies.
Pink’s high frequency counterpart is blue.
Red/high brown’s frequency counterpart is violet.
Both low and high frequencies are highlighted in grey noise. In the frequency spectrum, it is strongest at the top and bottom and weaker in the middle. Grey noise is typically perceived as white noise by the human ear.
Black noise is silence, which is the absence of sound.
The colours of sounds shifting towards higher frequencies are less frequently connected with sleep since the human ear is more sensitive to higher frequencies, but they can be effective to help disguise other high frequency sounds.

Advantages of sound

The terms «cushion of sound» or «blanket of noise» are widely used to describe white, pink, and red noise. They primarily benefit you and your baby by isolating you from background noise, masking abrupt changes or irregularities in environmental noise, and providing a constant noise environment around you and your child. This explains why people frequently prefer the sound of a regular CPAP machine to their partner’s erratic snoring.
White, pink, and red sounds serve primarily as a mask for any other noises that could otherwise interfere with sleep.

Depending on their sensitivities, people might prefer pink to white or red to pink, but the idea is always the same.

Common Claims

On the Internet, there are a lot of claims regarding white noise. Your infant sleeps better as a result of it. Those who utilise it can focus and stay focused. It improves memory. It calms you down. It reduces headache pain. It is useful for quick naps. It facilitates sound slumber at night. Tinnitus patients benefit from it. It also acts in the complete opposite in all these ways. It might become compulsive. Your child’s hearing may be harmed. That will exacerbate your tinnitus.

You can use a white noise machine to put your baby to sleep without worrying. There is no such thing as a baby sound addiction, and it’s a good idea to develop a sleep schedule. As they become older, your child will make sure their sleep schedules alter because they are continuously growing. If used properly, using a white noise machine won’t harm your child’s hearing. You should be aware of your machine’s capabilities and make sure the volume is set suitably for the distance between it and your infant. Some machines have the ability to play noises at high volumes.

The advantages of white noise have been the subject of numerous studies over the years. Links to some of these studies are provided below, but you should be aware that they were all conducted on very small sample sizes.

The number of studies done to date makes it impossible to draw firm conclusions about the relationship between white noise and sleep.

There haven’t been any extensive, reliable studies done on the impact of white (or other colour) noise on infant, child, or adult sleep.

Bottom Line

The best piece of advise we can give is to experiment and find what works for you and your infant. Your baby will probably fall asleep with the aid of sound. Most of your baby’s existence was spent inside your womb, where your body’s continual noise exposure affected him or her. Beyond that, your child should be assisted in anticipating and adjusting to sleep by anything that helps develop a routine around it.

Attempt white, pink, or red fake noises. Try listening to some of the world’s natural sounds, such as wind, fire, waves, rain, thunderstorms, and more. Try hearing sounds from appliances like vacuums, hair dryers, and washing machines. Try out some human noises like womb sounds, heartbeats, humming, and shushing. Don’t forget to include soothing music.

Keep experimenting until you find something that works for you and your child because every baby is unique, and certain noises may be effective for various children at various periods.

References

Noise-Induced Hearing Loss in Young People
Is My Baby Sleeping Enough? When Will We Sleep Longer?
Sleeping Like a Baby
Keep Your Sleeping Baby Safe and Practice Tummy Time
How Noise Affects Children