HIGH-PITCHED SOUNDS: CHARACTERISTICS AND EXAMPLES - PHYSICAL - 2024

High- pitched sounds are those high-frequency sounds that the human ear perceives as louder, as opposed to bass sounds, which are also called bass. In acoustics, the quality that distinguishes both types of sound is its pitch or height.

The property that makes a sound seem lower or higher is the frequency of the sound wave. This is defined as the number of cycles contained in the unit of time, usually oscillations / second or hertz (Hz) in the International System of measurements. The higher the number of Hertz, the higher the sound is.

The bird calls are high pitched sounds. Source: MaxPixel.

In addition to frequency, the intensity of the sound intervenes in the way the brain interprets whether a certain sound is higher than another. Why does a stronger sound seem sharper than a weaker sound, even if they have the same frequency?

The human ear is designed to perceive a wide range of frequencies ranging from 20 to 20,000 Hz (20 KHz), being more sensitive between 500 Hz and 5 KHz - the acoustic window -, according to the research carried out in the area of ​​Psychoacoustics, the science that studies how the brain perceives and interprets sounds.

Sound frequency range and human hearing

Regarding pitch or height, the audible frequency range in humans is subdivided into:

- Low frequencies, corresponding to bass sounds: 16 Hz - 256 Hz.

- Medium sounds: 256 Hz - 2 KHz.

- High frequencies, corresponding to sharp sounds: 2 KHz - 16 KHz.

Below 20 Hz is infrasound and above 20,000 Hz ultrasound. With age, the range of auditory perception tends to narrow, losing the ability to perceive some frequencies.

Sound detection in humans

Human hearing is extremely complex and requires a good interaction between the ear-brain duo, since the perception of sounds begins in the ear, where there are specialized cells that act as sensors until it reaches the brain, where the sensation occurs. definitive hearing.

Sound processing sequence in humans. Source: Wikimedia Commons.

Sound consists of pressure changes in the air, which are collected in the ear canal until reaching the eardrum, whose vibrations are transmitted to the ossicles that are in the middle ear.

The ossicles, in turn, are responsible for moving the fluid that fills the cochlea, a snail-shaped organ found in the inner ear. This fluid in motion sets in motion the hair cells that transform sound energy into electrical energy, to be received by the auditory nerve and carried by it to the brain.

Hair cells are true sound sensors. Those found in the innermost part of the cochlea better detect the low frequencies associated with bass sounds, while the outermost ones do so with high sounds.

Precisely the outermost area tends to deteriorate with age as it is more exposed, and that is why the hearing of high frequencies decreases over time.

Examples of high-pitched sounds

High-pitched sounds are everywhere, but it must be clarified that they are not pure sounds, with a single frequency, but combinations with a fundamental frequency that stands out among all of them.

The height of the human voices that are heard daily has a particular symbolism. For example, high-pitched voices can be associated with joy and laughter, as well as youth. Children's voices are high-pitched, while low voices are associated with maturity. An extremely deep voice can even be gloomy.

High frequencies also have the virtue of putting on alert when listening or even causing a start, that is why ambulances and police sirens are high-pitched sounds that indicate some kind of emergency.

When people are upset for any reason, they tend to sharpen the tone of their voice. Screams are high-pitched sounds that denote fear, outrage, or pain.

But in addition to female and youth voices, high-pitched sounds also come from many other sources:

- The song of the birds.

- Whistles and whistles.

- Musical instruments such as acoustic and electric guitar, violin, trumpet and flute.

- Train and ambulance sirens.

- The sound of waves in the ocean (generally equal to or greater than 20 KHz)

- Sounds present in industries such as metallurgy, construction, agriculture, wood and electronics.

- Bells

- Sounds of some animals such as the meowing of cats.

High-pitched sounds and hearing loss

Research points to the fact that continuous exposure to high-frequency sounds can lead to hearing loss and other health problems, such as hypertension and fatigue. Not to mention the communication problems it entails.

High-pitched desensitization makes it difficult to understand words that contain consonants such as F, T, or S, especially in environments with a lot of background noise. Losing the song of birds and not being able to properly enjoy music are other possible consequences.

For this reason, in extremely noisy work environments it is advisable to use hearing protection equipment.

Of course, hearing loss can also occur suddenly due to other causes such as infections, accidents or exposure to very high intensity sounds, such as an explosion for example. However, avoiding very noisy environments at high frequencies is a good way to prevent the decline in hearing acuity that occurs naturally with advancing age.

Sounds in the animal kingdom

It is interesting to know that hearing ranges in the animal kingdom are extremely varied. Many animals hear sounds that humans don't even remotely dream of hearing.

For example, elephants use infrasound to communicate, since low-frequency sounds can travel great distances in the extensive habitat of these intelligent mammals.

The reason is that sound waves experience diffraction, a property that allows them to evade obstacles of all kinds - natural accidents, buildings, openings - and continue to propagate. The lower the frequency of the wave, the more likely it is to diffract and travel further.

High-pitched sounds - high frequencies - have a harder time diffraction and that is why they get lost along the way. But this does not prevent animals such as bats from having developed the ability to detect frequencies greater than 100,000 Hz and use these sounds to locate themselves in their environment and hunt in total darkness. And is that the high frequencies are directional, while the low ones warp in the corners.

Both infrasound and ultrasound are used in the animal kingdom for various survival purposes, ranging from navigation, communication, paralyzing prey and even evading predators. Whales, tigers, cats, dogs, and other animals also use sounds outside the audible range to humans for these multiple purposes.

References

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