What Is a Frequency Spectrum?

Frequency spectrum is the abbreviation of frequency spectral density, which is the distribution curve of frequency. Complex oscillations are decomposed into resonance oscillations with different amplitudes and frequencies. The graph of the amplitudes of these resonance oscillations arranged by frequency is called the frequency spectrum. Spectrum is widely used in acoustics, optics and radio technology. Spectrum introduces the study of signals from the time domain to the frequency domain, which leads to a more intuitive understanding. The frequency spectrum of complex mechanical vibration is called mechanical vibration spectrum, the frequency spectrum of acoustic vibration is called acoustic spectrum, the frequency spectrum of optical vibration is called spectrum, and the frequency spectrum of electromagnetic vibration is called electromagnetic spectrum The spectrum is usually included in the range of the electromagnetic spectrum. Many basic properties of this complex vibration can be understood by analyzing the spectrum of various vibrations, so spectrum analysis has become a basic method for analyzing various complex vibrations.

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16 ~ 20KHz

This frequency range is actually inaudible to the hearing organs of the human ear, because the highest frequency of human ear hearing is 15.1KHz. However, people can pass the sound waves of 16-20KHz frequency felt by the human body, skull, and skull to the auditory brain region of the brain, and thus feel the existence of this sound wave. This frequency affects the tone, color, and emotion of the tone. If the frequency response range of the audio system does not reach this frequency range, the flavor of the tone will be lost; if this frequency is too strong, it will give a sense of cosmic sound, an illusion, and a mysterious Feeling makes people feel a sense of instability. Because most of these frequencies are the dissonance of the pitch and the tone frequency, a sense of instability is produced. This frequency is very low in tone. But it is very important. It is the expressive part of the timbre, which is often overlooked by some people, and even some people don't even feel its existence. ^[2]

12 ~ 16KHz

This is the high-frequency sound wave that can be heard by the human ear. It is the most expressive part of the timbre. It is the high-frequency overtones of some high-end musical instruments and treble percussion instruments, such as cymbals, bells, tambourines, sand hammers, copper brushes. The high-frequency overtones of percussion instruments, such as iron and triangle iron, can give people a "golden light" feeling, which strongly expresses the personality of various instruments. If this frequency component is insufficient, the timbre will lose color and lose its personality; if this frequency component is too strong, such as the exciter is too strong, the timbre will produce "burr" sharp noise, harsh high-frequency noise, This band should be given some appropriate attenuation. ^[2]

10 ~ 12KHz

This is the high-frequency overtone section of a treble brass instrument of a treble woodwind instrument, such as the metal sound of a treble wind instrument such as a flute, oboe, trumpet, piccolo. If this frequency is lacking, the sound will lose its luster and lose its personality; if this frequency is too strong, it will produce sharp noise and harshness.

8 ~ 10KHz

This frequency s sound is very obvious, affecting the clarity and transparency of the sound. If this frequency component is missing, the tone will become flat and dull; if this frequency component is too much, the tone will become sharp.

6 ~ 8KHz

This frequency affects the brightness of the tone, which is the frequency at which the human ear is sensitive to hearing and affects the clarity of the tone. If this frequency component is missing, the sound will become dim; if this frequency component is too strong, the sound will look serious.

5 ~ 6KHz

This frequency most affects the intelligibility and intelligibility of speech. If this frequency component is insufficient, the timbre appears ambiguous; if this frequency component is too strong, the timbre becomes sharp, and it is easy for people to have auditory fatigue.

4 ~ 5KHz

This frequency has an effect on the surface loudness of the instrument. If the amplitude of this frequency component is large, the loudness of the instrument will increase; if the intensity of this frequency becomes smaller, it will make people hear that the distance between the instrument and the human ear becomes longer; if the intensity of this frequency increases, Will make people feel that the distance between the instrument and the human ear is getting closer.

4KHz

This frequency is very penetrating. The resonance frequency of the human ear cavity is 1 ~ 4KHz, so the human ear is also very sensitive to this frequency. If the empty frequency component is too small, the hearing ability will be deteriorated, and the speech will become blurred. If this frequency component is too strong, a coughing sensation may occur, for example, when the frequency of the radio receiving station is not correct, the announcer often makes a coughing sound.

2 ~ 3KHz

This frequency is the most sensitive frequency band that affects the brightness of the sound. If this frequency is rich in components, the brightness of the tone will be enhanced. If the frequency is insufficient, the tone will become hazy; If the composition is too strong, the sound will look dull, stiff and unnatural.

1 ~ 2KHz

This frequency range has a clear sense of transparency and a strong sense of smoothness. If this frequency is lacking, the sound will be loose and out of touch; if this frequency is too strong, the sound will feel jumping.

800Hz

This frequency amplitude affects the strength of the sound. If this frequency is full, the sound will look strong and powerful; if this frequency is not enough, the sound will look slack, that is, the component characteristics below 800Hz are prominent, and the low-frequency components are obvious; and if this frequency is too large, throat Sound. Everyone has a larynx, and everyone has a certain larynx. If there is too much larynx in the timbre, it will lose the personality of the voice and the beauty of the timbre. Therefore, the sound engineer calls this frequency a "dangerous frequency" and should be used with caution.

500Hz ~ 1KHz

This frequency is the fundamental frequency range of the human voice and is an important frequency range. If this frequency is full, the outline of the human voice is clear, and the overall feeling is good; if this frequency is not wide enough, the voice will have a contraction; if this frequency is too strong, the voice will have a forward protruding feeling , So that the speech has a hearing feeling that enters the ear in advance.

300 ~ 500Hz

This frequency is the main frequency of the voice. The frequency of this band is full and the voice is strong. If the frequency range is insufficient, the sound will appear hollow and not solid. If the frequency range is too strong, the tone will become monotonous. Relatively speaking, there will be less low frequency components and less high frequency components. The timbre of the middle sound is very monotonous.

150 ~ 300Hz

This frequency affects the strength of the sound, especially the strength of the male voice. This frequency is the low frequency fundamental frequency of the male voice and also the root frequency of the chords in the tone. If this frequency component is lacking, the timbre will appear soft and fluttering, and the speech will become soft; if this frequency component is too strong, the sound will become stiff and unnatural, and there will be no characteristics.

100 ~ 150Hz

This frequency affects the fullness of the sound. If this frequency component is enhanced, a sense of space and thickness of room resonance will be produced; if this frequency component is missing, the tone will become thin and pale; if this frequency component is too strong, the tone will appear cloudy , The intelligibility of the voice becomes worse.

60 ~ 100Hz

This frequency affects the thickness of the sound and is the fundamental range of the bass. If this frequency is full, the sound will look thick and thick. If the frequency is not enough, the sound will become weak; if the frequency is too strong, the sound will have a low-frequency resonance sound and a roaring sound.

20 ~ 60Hz

This frequency affects the spatial sense of the tone, because the pitch of the music is mostly above this frequency. This frequency is the resonance frequency of the room or hall. If this frequency is adequately expressed, it will give people a feeling of being in the lobby; if this frequency is lacking, the tone will become empty; and if this frequency is too strong, it will produce a buzzing low frequency Resonant sounds have seriously affected the intelligibility and intelligibility of speech.