Low frequencies are usually talked about in relation to music, more broadly - to sounds in general. Low frequencies are opposed to high frequencies. This characteristic is directly related to the physical nature of the sound.
Sound as a physical phenomenon is elastic waves of mechanical vibrations that propagate in any medium - liquid, solid or gaseous.
Any wave, including sound, has two characteristics: amplitude and frequency. The latter is the number of repetitions of a periodic process (in this case, oscillations) per unit of time. There is a special unit for measuring frequency - hertz (Hz), which denotes the number of oscillations per second. 1 Hz is one oscillation per second.
Frequencies with a small number of oscillations per unit of time are called low, and with a large number of oscillations per unit time, they are called high.
Sound vibration frequency
With regard to sound, the vibration frequency will determine one of its characteristics subjectively perceived by a person - the pitch of the sound. In music, it is one of the main carriers of meaning. The higher the vibration frequency, the higher the sound.
The division of sounds into "high" and "low" is associated with the spatial associations that they evoke in a person. The higher the frequency of the sound, the more tension of the vocal cords requires its extraction, and the tension is associated with lifting, upward movement. High sounds when singing resonate in the tissues of the head ("above"), and low sounds - in the chest ("below").
The frequency response of a sound is closely related to its timbre. Even within the same musical instrument, high and low sounds will be “colored” differently.
The lower limit of the frequencies that a person is able to perceive as an audible sound lies in the region of 16-20 Hz. Frequencies up to 120 Hz are considered low.
The effect of low frequencies on humans
Low frequencies give the musical fabric a special beauty. In an orchestra or ensemble, instruments that produce low sounds are the “foundation” that puts the sound on a solid foundation. Any mixed or male choir is decorated with octavist bass. But low frequencies cannot be overused.
Especially dangerous are low frequencies lying outside the range of auditory perception - infrasound, vibrations less than 16 Hz. There are many chilling maritime stories about "ghost ships" from which all people disappeared in a strange way. Some stories belong to the legends, others are documented, for example, the case of the court "Maria Celeste", found in 1872. One of the possible explanations for such tragedies is associated with the "voice of the sea" - a low-frequency sound generated by the sea during underwater volcanic eruptions. This infrasound affects the nervous system, causing feelings of horror and fits of insanity, which makes people throw themselves overboard.
The danger posed by infrasounds does not prevent some composers from using them in their works. This is what, for example, A. Scriabin did in the symphonic poem "Prometheus". This work, of course, does not provoke fits of madness, but it does cause horror.
In modern pop music, sounds are used in abundance that are at the lower limit of the frequency range of auditory perception. Some people, when listening to such music, develop pains in the solar plexus area, headaches, nausea, and fatigue. For other people, such low frequencies cause a pleasant state of mind that is called "high" in teenage jargon. True, this state is associated with exaggerated physical activity with a weakening of control from the side of consciousness. In part, this is comparable to drug intoxication, it is not by chance that it is denoted by the same slang word.
Low frequencies can be dangerous weapons and must be handled with care.
