Whether it's human voice,singing voice,or instrument voice,they are not a single tone,but a compound sound.It is composed of the fundamental sound and a series of overtones.These overtones are the digits of the fundamental frequency,which are called harmonics in physics,harmonics in electroacoustics,and overtones in music.It has a very important impact on the characteristics of timbre.The number and amplitude of these overtones form the frequency characteristic curve of timbre.This curve embodies the expressive power of timbre.For example,the lowest frequency of a piano is 27.5Hz,and the highest audio rate is 4186Hz.However,a piano has more than ten overtones,and its high frequency can reach 10kHx~20kHz.Generally,16 overtones or 24 overtones can be measured.These overtones can be divided into low-frequency overtones,mid-frequency overtones,and high-frequency overtones,.If the amplitude of low-frequency overtones is strong,the timbre will appear thick;The amplitude of mid frequency overtones is relatively strong,resulting in a rounded,natural,and harmonious tone;The amplitude of high-frequency overtones is relatively strong,resulting in a bright,clear,and strong analytical tone.
　　The spectral curve connects the vertices of the various early morning amplitudes of the timbre in coordinates,and this package route is the spectral curve of this early morning color.
　　The spectral curves of a timbre are different,depending on the material structure,state,and intensity of the speaker,as well as the resonance of the body.
　　What is the best sound quality?
　　According to the perspective of Italian bel canto,the intensity of the fundamental to the 16th overtone is connected in a straight line on coordinates,which is called the best bel canto line,as shown in Figure 2.So,which timbre has a frequency characteristic curve that is closer to this straight line,and which timbre has the most balanced proportion of low,medium,and high frequency overtones,and its artistic expression of timbre is also the best.
　　In terms of beautifying and embellishing the human voice,the four stage equalizer in the input channel on the mixing table can be used to process the frequency of the sound,in order to improve the artistic expression of the sound.The four band equalizers in the mixing station are divided into four frequency bands.According to data from the Berlin Institute of Music,they are:
　　1:6-16 kHz,affecting the expressive and analytical power of the sound.
　　2:MID HF:600Hz~6?KHz affects the brightness and clarity of the sound.
　　3:MID HF:200-600Hz,affecting timbre,strength,and firmness.
　　4:LF:20-200Hz,affecting the mixing thickness and fullness of the timbre.
　　If the frequency in the high-frequency range is too weak,its timbre will become lost in color,charm,and personality;If the high-frequency frequency is too strong,the sound will become sharp,hoarse,and harsh.
　　If the frequency in the mid to high frequency range is too weak,the tone will become dim and hazy;If the frequency in the mid to high frequency range is too strong,its tone will become dull.
　　If the frequency in the mid to low frequency range is too weak,the timbre will become empty,weak,and soft;If the frequency in the mid to low frequency range is too strong,the sound will become stiff and lose vitality.
　　If the frequency in the low frequency range is too weak,the tone will become thin and pale;If the frequency in the low frequency range is too strong,the sound will become cloudy and unclear.
　　To make the tone beautiful,it is necessary to have rich and layered overtones,making the song sound beautiful and pleasing to the audience.The amount of improvement should not be too strong.Excessive LF(low frequency)and unclear sound;Excessive HF(treble),with sharp and piercing sound.After upgrading a certain frequency band,the impact on other frequency bands should also be considered,and the overall clarity and fullness of the singing should be considered.
　　Below are several tuning techniques for curved vocals.
　　1:Tune the host
　　The host is mostly a young lady,with clear and fluent speech characteristics,rich in facial expressions.She can influence the emotions of the audience,so she needs to adjust her tone well.
　　Low key type:softly spoken,with delicate emotions,can be picked up at close range.The microphone is very close to the mouth shape,which can increase the sense of familiarity and pick up delicate and weak tones.Its disadvantage is the presence of proximity effect and strong low-frequency.
　　Specific handling methods:
　　To attenuate LF:attenuate around 6dB around 100Hz,with a maximum attenuation of 10dB.
　　For MID:Increase 3-6dB at 250Hz-2kHz.250Hz-2kHz is an important frequency band for language.
　　Attenuate 3-6dB in the frequency band above HF:6KHz to reduce high-frequency noise.
　　The host's microphone should not use an effect processor for reverb(REV)and echo(ECHO)processing,otherwise it will lose its realism and familiarity.
　　2:Tune for ordinary people:
　　In the concert hall,there are some singing enthusiasts and amateur singers,as well as some who only entertain themselves and sing for themselves.Some of them have not received basic professional training,lack singing skills,and even have poor noise and do not know how to use microphones.Among them,male voices are prone to throat and hoarse sounds,while female voices are prone to breath and vocal cord noise.
　　To eliminate the above phenomena,the following specific treatment methods are adopted.
　　Below 100Hz,it should be cut off to eliminate low-frequency noise and make the sound more pure.
　　At 500-800Hz,it is necessary to attenuate the sound slightly to avoid being too stiff.
　　Increase the MID frequency band by 3-6dB to enhance brightness and make the sound clear and bright;
　　Most people have lower voices and lack loudness,so the volume should be turned on higher;The frequency range of 200-300Hz can also be increased to increase the loudness of the sound.
　　Amateur singers have a limited dynamic range,so do not use automatic volume control.
　　3:Tune professional singers:
　　There are often professional singers in the concert hall who are invited by friends to be guests.Sometimes,they sing two songs to cheer up their friends and guests.Professional singers have a loud singing voice,with a certain level of basic skills in vocalization,sighing,enunciation,and resonance singing,and each person has a certain singing style.
　　Tuning requirements:
　　To understand the vocal characteristics,online genres,and high,medium,and low overtones of singers;
　　To understand the singer's range width and dynamic range;
　　To be familiar with the song,lyrics,and emotions,the basic technique of adjusting the early morning should be consistent with the artistic conception of the song;
　　Pay attention to the style of the song and the singer's singing emotions;
　　The level of the microphone should be high:broadband response,small distortion,and large dynamic.
　　Actors stand on the stage of the music industry,utilizing the sound field to create both electric and natural tones.So,it is required that the music industry has good acoustic characteristics.
　　Female voice:Female voice is prone to producing S sound(hissing)in the high-frequency part;Attenuated by 3dB at 7-10KHz,S sound can be eliminated.
　　Male voice:The range of male voice is one octave lower than that of female voice,with a frequency one fold lower.It attenuates by about 3dB at 100Hz,which can increase clarity.
　　Contributed by Guangzhou Tianya Audio Co.,Ltd