1 December 2023

The world around us is full of sounds, some soft and delicate, others shrill and energetic. These sounds are part of the audible spectrum, a fascinating physical phenomenon that allows us to perceive and experience the diversity of sound frequencies present in our environment. In this article, we will look at the interval and the characteristics that define this range of sounds that we can hear. From the lowest and lowest tones to the high and vibrant, the audible spectrum offers us a window into music, speech and the rich nuances of the acoustic world around us. Let’s discover together what it is, what its range is and what elements make it as fundamental as it is fascinating in our listening experience.

Definition and concept of audible spectrum

Also called tonal field, it refers to the range of sound frequencies that the human ear can perceive. According to physics these sound waves propagate in the form of vibrations that are transmitted through the air or other means. The audible frequency range for most people is approximately between 20 Hz and 20,000 Hz.

However, hearing ability may vary depending on age and other individual factors. The lowest waves correspond to low sounds, such as the purr of an engine or the noise of thunder, while the highest ones are associated with high-pitched sounds, such as the chirp of a bird. The study of its physical properties is important to understand the behavior of sound waves within the audible range for human beings.

In terms of sound pressure levels, the human hearing threshold it is set around 0 decibel (dB). As sound intensity increases, sound pressure levels increase.

The auditory pain threshold, where sound it becomes uncomfortable or even harmful, varies for each individual, but is generally in the 120-130 dB range. The dynamic range of the human ear, that is, the difference between the softest sound that can be heard and the loudest sound that can be tolerated, is approximately 120 dB.

There is also something called an octave of the audible spectrum, referring to the interval that is twice the frequency of the original note. In other words, each octave is a frequency doubling. For example, if a note has a frequency of 440 Hz, the next octave would be 880 Hz, then 1760 Hz, and so on.

What are the characteristics of the audible spectrum?

This range of frequencies that the human ear can perceive presents the following characteristics:

  1. Frequency range: It ranges from approximately 20 Hz (hertz) to 20,000 Hz, although these numbers can vary from person to person.
  2. Sensitivity: The human ear is most sensitive to certain frequencies within the audible spectrum, around the 2,000 – 5,000Hz. This region is known as the ‘hearing sensitivity zone’.
  3. Volume perception: The volume or amplitude of a sound determines its perceived intensity. The human ear is more sensitive to sounds higher intensity in the middle range of the tonal field.
  4. Tone discrimination: The human ear is capable of distinguishing between different tones or frequencies within the audible spectrum. This is essential for the perception of music and language.
  5. Hearing loss: Some people may experience a decrease in their ability to hear certain frequencies as they age or due to hearing damage. This is known as hearing loss and can affect the ability to perceive the entire audible spectrum.

It is important to note that these characteristics can vary from person to person and that there are individual differences in the perception of the tonal field.

What is the range of the audible spectrum?

Although the range may vary slightly between individuals, it is generally accepted that the audible spectrum encompasses approximate intervals of 20Hz to 20,000Hz (20kHz). Which corresponds to wavelengths from about 1.7 meters to 17 millimeters.

The lowest frequencies, below 20 Hz, are known as infrasound and are generally not audible to most people, although they can be felt as vibrations. On the other hand, the higher intervals, above 20,000 Hz, are called ultrasound and they are also not perceptible to most humans.

It is important to note that the ability to hear certain frequencies can vary depending on the age and hearing health of each person. As we age, it’s common for high-frequency hearing to gradually decline, which can cause higher intervals are less audible.

How is the audible spectrum measured?

It is measured in hertz (Hz), which represents the frequency of sound waves. Sound measurement devices such as microphones and spectrum analyzers are used. To find out how much it measures, equipment called spectrum analyzers or audio spectrometers. These devices capture and graphically represent the frequency distribution of a particular sound. They can also provide information about the intensity or amplitude of each frequency. Spectrum analyzers typically display the audible spectrum on a bar graph or spectrogram, which shows amplitude as a function of time and frequency.

What is the relationship between pitch, timbre, and audible spectrum?

Pitch refers to the perceived frequency of a sound, timbre refers to the distinctive quality or characteristic of the sound, and the pitch field is the graphical representation of the different intervals present in a sound. Timbre and the audible spectrum are related, since the timbre of a sound is determined by the frequency combination present in their audible spectrum. Pitch, timbre, and the audible spectrum are related to the perception and characteristics of sound.

Tone: It refers to the quality of sound that we allows to distinguish if it is acute or serious. It is related to the frequency of a sound wave. The higher the frequency of a sound wave, the higher the perceived pitch will be, while if the frequency is low, the pitch will be low. For example, a whistle produces a high pitched tone, while a drum produces a low pitched tone.

Doorbell: It is the quality that allows us to distinguish between different sound sources, even when two sounds have the same frequency and amplitude. It’s what makes a guitar sound sound different from a flute sound, even though they both have the same root note. Timbre is determined by the combination of harmonics and the waveform of a sound.

audible spectrum: It means to the frequency range that the human ear is capable of perceiving. For most people, the audible spectrum ranges from approximately 20 Hz (low frequency) to 20,000 Hz (high frequency). These represent the upper and lower limits of average human hearing, but it’s important to note that hearing ability can vary from person to person.

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