What Is an Audio Equalizer?

Equalizer is an electronic device that can separately adjust the amplification of electrical signals of various frequency components. Through the adjustment of electrical signals of different frequencies, it compensates the defects of speakers and sound fields, compensates and modifies various sound sources and other special functions. , Generally, the equalizer on the mixer can only adjust the high frequency, intermediate frequency, and low frequency three-band electric signals. Equalizers can be divided into three categories: graphic equalizers, parametric equalizers, and room equalizers.

Sound equalizer

Equalizer is used to correct the attenuation (ie transmission loss) and phase difference caused by different frequencies.

(1) According to the working frequency, it can be divided into V-band equalizer and U-band equalizer.

(2) Divided into fixed equalizer and variable equalizer according to the equalization amount.

(3) Frequency response equalizer. In the actual system, there is often a case where the level of a certain channel is higher than that of other channels. At this time, the above-mentioned equalizer cannot solve the problem, and a frequency response equalizer for a certain frequency should be used.

Equalizer is a commonly used device in wire television system. Its quality has a great impact on the system. It usually uses the insertion loss, equalization value, equalization deviation, reflection loss, current carrying capacity and other indicators to measure its performance.

(1) Insertion loss. At the upper frequency of the operating frequency, the difference between the decibels of the input power and the output power of the equalizer is the insertion loss.

(2) The equilibrium value. In order to represent the attenuation of the equalizer-frequency characteristics and convenient selection, there are two ways to express the equalization value: one is the equalization amount, and the other is the equivalent equalization value.

(3) Equilibrium deviation. Because the characteristics of the equalizer cannot be completely complementary to the attenuation characteristics of the cable, there is a certain balance deviation. The equalization deviation is the difference between the equilibrium value of the specified frequency point and the theoretical average density value in the working frequency band. The smaller the equalization deviation value, the better the compensation effect.

(4) Reflection loss. It is a measure of how well the input and output of the equalizer match. The larger the reflection loss value, the better the impedance matching of the port.

(5) Ampacity. In a CATV system using centralized power supply, the equalizer should be able to provide a current path for subsequent amplifiers. This equalizer is called a channel-type (feed-type) equalizer. No need for ampacity.

Graphic Equalizer: Also known as graphic equalizer, the distribution of push-pull keys on the panel can intuitively reflect the tuned equalization compensation curve. The improvement and attenuation of each frequency is clear at a glance. It uses constant Q technology and A push-pull potentiometer is provided at the point. The frequency bandwidth of the filter is always the same regardless of whether a certain frequency is boosted or attenuated. The commonly used professional graphic equalizer is to divide the 20Hz ~ 20kHz signal into 10 bands, 15 bands, 27 bands, and 31 bands for adjustment. In this way, people choose different frequency equalizers according to different requirements. Generally, the frequency points of the 10-band equalizer are distributed in octave intervals. In general, the 15-band equalizer is a 2/3 octave equalizer. It is used for professional sound reinforcement. The / 3 octave equalizer is mostly used in situations where fine compensation is needed. The illustrated equalizer has a simple structure and is intuitive.

Parametric Equalizer: Also known as parametric equalizer, an equalizer that can fine-tune various parameters for equalization adjustment.

Room Equalizer: An equalizer used to adjust the frequency response characteristic curve in a room. Due to the different absorption (or reflection) of different frequencies by decorative materials and the effect of normal resonance, the coloration of the room must be used. The frequency defects in the built-in sound are adjusted objectively.

The finer the frequency band is divided, the sharper the peak is adjusted, that is, the higher the Q value (quality factor), the more detailed the compensation is when adjusting. The thicker the frequency band is, the wider the adjusted peak is. When the sound field transmission frequency characteristic curve is more complicated, More difficult to compensate.

Where paragraphiceq is a parametric graphic equalizer and graphiceq is a graphic equalizer. Multi-band variable equalizer with sliding controller as parameter adjustment. The logo under the sliding controller corresponds to its frequency response. The center frequency and bandwidth of each band are fixed.

Making music is inseparable

Basic introduction to sound equalizer

In audio equipment, a sound equalizer is an electronic device that can individually adjust the amplification of electrical signals of various frequency components. By adjusting electrical signals of various frequencies, it can compensate for defects in speakers and sound fields, and compensate and modify various The sound source and other special functions, the equalizer on the general mixer can only adjust the high frequency, intermediate frequency and low frequency three-band frequency electric signals respectively.

Strictly speaking, you should first use the equalizer to correct the sound according to the frequency response curve of the sound, that is, the frequency response curve of the sound is not a horizontal straight line, but in order to truly restore the sound, we can adjust the original by adjusting the equalizer. The curve becomes straight. But most of my friends don't have this condition, and don't know the frequency response curve of the earphone or earphone, so we can only adjust it according to our own hearing.

Sound equalizer parts function

First let's look at the role of each part after the equalizer segmentation:

1. 20Hz--60Hz part

This period of improvement can give the music a strong feeling, giving a very loud feeling, such as thunder. It is a powerful feeling in music. If the lift is too high, it will become cloudy again, resulting in poor clarity, especially for low-frequency response and heavy low-frequency audio equipment.

2. 60Hz--250Hz part

This section is the low-frequency structure of the music. They contain the basic sound of the rhythm part, including the fundamental sound and the main sound of the rhythm sound. Its ratio to the high and middle notes constitutes the balanced nature of the tone structure. Raising this section can make the sound full, and excessive lifting will make a rumbling sound. Attenuating these two sections makes the sound thin.

3 250Hz--2KHz part

This section contains the low-frequency harmonics of most instruments. If it is boosted too much, it will sound like a phone. Excessive boosting of 600Hz and 1kHz will make the sound sound like a horn. If the 3kHz is increased too much, it will mask the speech recognition sound, that is, the speech is not clear, and make the lip sound "mbv" difficult to distinguish. For example, excessively increasing 1kHz and 3kHz will make the sound metallic. Because the human ear is more sensitive to this frequency band, this segment is usually not adjusted. Excessively raising this segment will cause hearing fatigue.

4 2KHz--4kHz part

This frequency is an intermediate frequency. If it is raised too high, it will cover the speech recognition sound, especially if the 3kHz is raised too high, it will cause hearing fatigue.

5. 4kHz--5KHz part

This is a band with a sense of presence, which affects the intelligibility of sounds such as language and musical instruments. Increasing this frequency band makes people feel that the distance between the sound source and the listener seems a little closer; attenuating 5kHz will make the distance of the sound farther; if raising 6dB around 5kHz, the sound of the entire mixed sound will be The power is increased by 3dB.

6. 6kHz--16kHz part

This band controls the brightness, brilliance and clarity of the sound. Generally speaking, raising these sections makes the sound louder, but not clear. It is unlikely to cause tooth sounds to be too loud. When the sound is attenuated, the sound becomes clear, but the sound is not loud.

The equalizer can also be set according to the curve of the listening door limit, so that the ear can most easily feel the sound, which is the most natural and best! As shown below, we increase the number of DBs at low and high frequencies.

In this way, the low and high frequencies can be felt by the ears naturally, that is to say, the optimal EQ setting should be consistent with this curve.

The CD recorded the edited sound source signal very well when recording, and the sound effect was adjusted when the CD was made, so we can think that no compensation is needed. mp3 is not the same. When compressing, there will be losses in the three parts of high, middle and low frequency. Generally speaking, the high and low ends are lost, and the middle frequency part is largely preserved. So the approach I took was to adjust by comparing the CD and mp3 file playback.

Presets have several modes such as pop, rock, jazz, classic, vocal, etc. What's the use?

In fact, these are set according to different music styles. The frequency response curve is introduced below.

pop: pop music. It requires that the combination of both vocal and instrumental music is average, so the fluctuation of the curve is not very large.

rock: rock music. Its high and low ends are greatly improved, the bass makes the music strong and powerful, the rhythm is strong, and the treble is clear and even harsh.

jazz: Jazz. It boosts the 3-5kHz part to enhance the presence.

classic: classical music. It also enhances the high and low parts, mainly highlighting the performance of the instrument.

vocal: Voice. The frequency range of the sound made by a human throat is relatively narrow, mainly concentrated in the intermediate frequency portion.

The above part was reposted. Personally I think Xiaoai is a good match!

Sound equalizer adjustment method

Subwoofer: 20Hz-40Hz, when the sound is strong and powerful. Able to control thunder, bass drum, pipe organ and bass sounds. Excessive lifting can make the music muddy.

Bass: 40Hz-150Hz, which is the basic part of sound. Its energy accounts for 70% of the entire audio energy, and it is an important component for expressing music style. When appropriate, the bass is relaxed properly, the sound is full and soft, and the sound is thin at 150Hz. When it is excessively raised, it will make the sound dull, the brightness will decrease, and the nasal sound will increase.

Mid bass: 150Hz-500Hz, it is the structural part of the sound. The human voice is located at this position. When it is insufficient, the singing sound will be overwhelmed by music. When the boost is too high, the bass will become stiff, and it will be increased by 3-6dB at 300Hz. If reverberation is added, it will seriously affect the clarity of the sound.

Middle tone: 500Hz-2KHz, including the low harmonics and overtones of most instruments, is the characteristic tone of snare drums and percussion instruments. When appropriate, the sound is clear and bright, and when it is insufficient, the sound is hazy. Excessive lift produces a phone-like sound.

Middle and high notes: 2KHz-5KHz, is the characteristic sound of string music (the sound of bow and string capricorn pulling, the sound of fingers touching the string during playing). When it is insufficient, the penetration of the sound decreases, and when it is too strong, it will mask the recognition of language syllables.

Treble: 7KHz-8KHz, it is the frequency that affects the sound layering. Excessive lifting will make piccolo and flute sounds prominent, accentuate the tooth sounds of the language, and make the tone fluffy.

Extremely high pitch: 8KHz-10KHz When appropriate, the triangle metal and the vertical metal permeability is high, the rhythm of the sand clock is clear and legible. Excessive lifting will make the sound unnatural and easily burn out the high-frequency unit.

A balanced and pleasant sound should be:

Below 150Hz (bass) should be plump, soft and flexible

150Hz-500Hz (middle and low) should be thick and powerful and not turbid

500Hz-5KHz (medium and treble) should be bright and transparent without being stiff

Above 5KHz (treble) should be slender, round and not sharp.

When the whole frequency response characteristics are flat: the sound is naturally full and flexible, and the levels are clear and pleasant. When the frequency response is multi-peak and valley: the sound is rough and turbid, the treble is harsh and hairy, and the non-layered sound reinforcement is prone to feedback howling.

Frequency characteristics:

30 ~ 60Hz It is difficult for human ears to feel dull without considerable loudness.

60 ~ 100Hz Heavy 80Hz can produce a strong "heavy feeling" effect, high loudness will not give people a comfortable feeling, it can give people a strong stimulating effect.

100 ~ 200Hz fullness

The 200 ~ 500Hz velocity is easy to cause the boring mood.

500 ~ 1KHz If it is increased by 10dB near 800Hz, it will obviously produce a sense of noise and narrowness.

1K ~ 2KHz translucent near 2800Kz has the greatest relationship with brightness.

2K ~ 4Kz The sharp 6800Hz forms a shrill, sharp feeling.

4K ~ 8Kz crisp 3400Hz easily cause hearing fatigue.

8K ~ 16Kz Slim> 7.5KHz The sound is clear and slender.

Development Trend of Sound Equalizer

An equalizer made up of digital filters is called a digital equalizer. A digital equalizer can be used to create a graphic EQ. It can be a parametric EQ or an EQ with both. It not only has excellent performance indicators, It is easy to operate, and can also store frequency response equalization characteristics for multiple purposes at the same time, which can be selected for different program requirements. It can store up to 99 frequency response characteristic curves. SONY's SRP-E300 is a versatile 2-channel digital equalizer with 10-band parametric equalization and 29-band graphic equalizer. It can work simultaneously or independently, with limiter and noise gate functions, high-precision 48kHz sampling, 20 Bit linear analog-to-digital / digital-to-analog conversion; with analog and digital input / output; RS-232C C interface, which can be used for external remote control. Its appearance will gradually phase out ordinary analog equalizers. Very cost-effective products.

Notes on sound equalizer

1. Most of the sound in the 20 to 40 band sounds like a soft bass, not a strong one. You can know by experiment. See what effect it will have on boosting this band to the floor drum.

2. 40 to 150 is the basis of the sound, but it accounts for less than 70%, and the nasal sound of the human voice is not in this frequency band, about 250.

3. The frequency band from 150 to 500 is a frequency band that must be handled with great care. You must not increase the frequency to obtain human voice. A little carelessness will result in a mass.

4 "Excessively increasing 3-6dB at 300Hz. If reverberation is added, it will seriously affect the clarity of the sound." It should be said that as long as reverberation is added to the low frequency, it will affect the clarity of the sound. Of course, this rule is not very important in current mixing techniques. Because we often see them in the studios in Europe, America, Hong Kong and Taiwan, and they have ultra-short reverbs for floor drums and bass.