Discuss about Tuning Skills for Mixer / Console

A simple and complete sound system , from start to finish at least include a microphone, mixer , amplifier, speakers four units. Of course , the actual use of the sound system tuner is much more complicated than this , when the multi-channel signal input , in addition to the microphone , there will be a DVD player ( or CD player ) , cassette player , MD deck, etc. . In addition, the processing will be used in professional audio equipment such as reverb , delay , actuators, pressure limiter , expander , equalizers, crossovers , etc. However, the entire workflow , the mixer is undoubtedly located in key positions and the hub plays a connecting role , thus tuner to adjust it plays an important role.

A mixer function
Before using the mixer, the mixer functions for us to have a full understanding. Mixer is a professional audio system is the most important equipment, a professional sound system is often based on the core of the mixer . Common mixer can accept 8 to 24 channels of different signals and these signals are processed in the timbre adjustment and amplitude. In general , the mixer has four main functions.

The first function is to program signal amplification. After a variety of signals from different sources into the mixer program and its various signals are not required to put a lot of the same , so the mixer must be able to handle different signals . Various musical instruments , such as the human voice signal and the signal amplitude is not the same , of course, need to be treated separately .

The second function of the signals are separately adjusted frequency ( i.e., tuning ) . We know that different signals , due to its spectral distribution , and other aspects of the harmonic components , the formation of a different tone , and the impact of buildings on the sound so that sounds great changes . Sound engineer PA according to different environment, different voices into the mixer signals are processed to make it sound as close to the original. Each mixer channel has the same processing means , such as: 3-band EQ , gain control , high-pass filters.

The third function is the combined signal . Mixer will be adjusted after each signal , to a variety of signals into the standard left and right channels ( stereo ) in the form of output, the input signal is used as a device to the next level , which is the most basic functions .

The fourth function is the distribution function . In addition to the main output of the mixer stereo , but also provide two or more auxiliary output signals , such signals have two purposes , one stereo listening room or stage to listen to ; second is to do with the effect of the excitation signal .

It was also a simple function summarized as follows:

* Pickup signal , amplifies ;
* Press the need for high , middle and bass tone equalization ;
* The signal sent by the need to be grouped around the bus or control ;
* On the auxiliary bus signals into artistic treatment 

* Output control as required .

However, no matter how expression , its function is the same. The tuner must all work to the mixer function as the core to expand .

Mixer features two partitions
1.When we first came into contact with the mixer , it is easy on the panel, it will be colorful , the number of knobs and putting numerous dazzled and overwhelmed . But in fact , the significance of faders and knobs for each channel are exactly the same, so we only need to learn how to focus on one channel you can use the platform of a comprehensive master tuning .

2.We usually are exposed to the mixer 8 to 24 of the road, less 4 , while large ones up to 96 -way there even more . However, regardless of ones more or less , the control console for each path is divided into two parts, the master and auxiliary control . There are separate auxiliary signal output can be realized in the same mixer can simultaneously output mix two or more signals .

Now, let us make a channel mixer section anatomy, as shown in Figure 1. This is a 16-channel mixing console all the way to the circuit anatomy , signal input from the left , then the gain , EQ , volume pushed to , pan and auxiliary partial control , the final output from the right .

1 signal input
Each channel has one or several specifications of the signal input port for connecting the system recorder, audio , samplers or synthesizers and other audio output port , or plug in the moving coil , capacitors , microphones , etc. Balanced inputs mainly used for microphone input , unbalanced inputs are mainly used for line input. It should be noted that, when using a condenser microphone , 48V capacitor microphone power switch must be turned on.

2.Gain knob (trim)


And the input is generally an even firmness adjustment knob called gain knob (trim), is used to adjust the input signal , i.e., when the signal is too strong for its reduction is too weak to enhanced ( sometimes the gain knob is an attenuator button "pad" instead of when the button is pressed or lifted input signal is doing a certain level of attenuation ) . As the voice input gain knob is the first pass of the mixer , adjust the appropriate audience tuning to ensure that the processing circuit to receive the full level and "clean " signal.

3 volume fader
When the gain knob set up, you can use the volume fader channel ( or volume knob is usually located in the lower end of the mixer panel ) to determine if the channel signal is sent to the volume of the bus. Fader is actually an attenuator output signal for the channel attenuation . When the slider is located in the lower end ( located at the left or the volume knob ) , the attenuated signal is infinite , then, no signal is output to the channel .

4 panning (PAN) knob
In the top of the volume fader , you can find a pan (PAN) knob , which is used to adjust the position of the channel signal in the left and right stereo speakers between .


5 mute (MUTE) and Solo (SOLO) button
Some stand between the volume fader and pan knob also designed two buttons that mute (MUTE) and Solo (SOLO) button. Mute button can not move the volume fader , it will mix bus signal to close the channel. When the output level of the channel has been accurately adjusted , and do not want to touch it again , this feature is obviously useful. When the solo button is pressed, the button is not pressed other solo passage does not say anything .

6 balanced
The vast majority mixer provides a certain channel equalization. Many are not very professional mixers are provided segmented equalization , reflected in the console is labeled "treble" and "bass" the two knobs , above , and when the two knobs to adjust lower than the frequency of the predetermined signal manufacturer , i.e. boost or attenuation. The above is also commonly referred to as two balanced, while the three -band EQ is more than one pair of bands (mid) be boost or cut the knob. Other mixers also added a selection of knobs IF point , which we call semi-parametric frequency equalization, and fully parametric equalizer IF center frequency can not only selected , but also choose to implement some frequency range boost or attenuation.

7 aux send (SEND, also known as effects send ) button
General design of each channel mixer 2 to 6 aux sends button. These knobs can control the amount of channel signal sent to each auxiliary signal output port (Aux SEND) , the signals of several channels simultaneously auxiliary out to an auxiliary port through the auxiliary knob. When the auxiliary output port connected effects, the output signal from the auxiliary port handled through the effects return to the effects of the mixer output to the auxiliary input port return (Aux RETURN), and then mixed with bus signals .

Volume control knob auxiliary signal returns are generally arranged in a part of the total wire mixer right. In the live recording , the auxiliary port can also be used to connect the headphone amplifier for multiple singers on the song while listening .

8 tape / line (Tape / Line) toggle switch
Multitrack recording system designed for the large mixer Each channel has a tape / line (Tape / Line) toggle switch . This switch can determine the input source for each channel is independent of each rail output mic / line input source or multi-track machine . When making multi-track recording , this switch should be placed in the line input state ; After the recording is finished , when multitrack mixdown signal , the switch should be placed in the tape input state, then , is to adjust each channel fader is actually more than each rail track machine semaphore signal output to the stereo bus.

9 breakpoint insertion port (INSERT)
Some mixer for each channel in addition to its spoken input estuary above , there is a breakpoint insertion port (INSERT), for connecting l / 4 inch stereo plug ( divided into head -Tip, Ring -Ring, set pipe -Sleeve three parts ) . When this does not plug into the mouth of the channel signal flow through each part of the above mixer for processing ; When plug access, the input signal of the channel is disconnected , sent by the Tip section of the plug to the external effects the signal processed by the return portion of the Ring to the channel , and then gain , EQ , pan, volume, etc. to adjust the final output of the mixer stereo bus. Like actuators, pressure limiter , etc. In this way generally connected with the mixer . In this way can only effect of a channel signals are processed without the use of effects send and return controls .

10. The bus control
Eventually, the output signal of each channel are mixed together , and then enter the stereo bus . There are two general bus control section controls the left / right channel ( or a ) master volume fader , volume control to adjust the effect return button , headphone output volume control knob , auxiliary output volume control ( auxiliary output port of signals are mixed-signal part or all channels ) . Auxiliary output on a variety of flexible use of space to do this no more explanation.

11. UV indicator
A mixer generally have two or more VU (Volume Unit acronym , meaning the volume indicator) indicator. Some indicators are kind of old-fashioned pointer table , some of them are LED (light emitting diode ) mode level meter. Some consoles can be switched with a different level of the indicator shows the bus and channels ; while others are designed for each channel and the bus has its own VU indicator.
Three mixer tuning skills

Mixer functions and functional areas we have a clear understanding , then the next step we can adjust a specific mixer . There are many aspects of tuning skills , but summed up the main artistic process sound compensation , adjust volume and sound signals , where the two main front speakers .

1 sound compensation
Compensating sound mixer to combine the sound source processing, also is not only a technical art , and should be combined with the audience psychoacoustic . Compensation is the use of sound quality compensation, adjust the center frequency of the band to change the sound of the tone. Sound compensation must follow these guidelines .

( 1 ) Bass Compensation
16Hz ~ 64Hz for the contrabass , the existing instruments can play the contrabass is the organ that can play the 16Hz, such low frequencies the human ear can not hear normally , but the body can feel ; person from 20Hz ~ 64Hz ear is able to hear , but you must use the hi-fi equipment in order to play it. Is from 63Hz ~ 250Hz bass , bass compensation it is our top priority , this band of music is very important, it is the foundation of the music , the bass rhythm-based instruments belong to this band , this kind of musical instrument sound adjustment good or bad, determines the musical skeleton is complete. Thus , the low-frequency characteristic use flat line , so you can make the sound full and natural , of course , also be based on the requirements and preferences of the instrument to compensate .

( 2 ) Compensation Alto
From 250Hz ~ 2000Hz as the bass , this band in the transmission and recording of the most susceptible to damage, are the backbone of the sound. 2000Hz ~ 4000Hz for the treble region , this band of clarity and brightness of the sound has an important contribution to our most important regulatory target . If the sound is muddy, dark timbre enhance this band , excellent sound attenuation can make it soft , you can enhance the sound muffled when you make it brighter , but will enhance the sound too harsh . Language or singing usually have to adjust the band.

( 3 ) treble compensation
From 4000Hz ~ 8000Hz to treble , treble can be kept on the flat line features, while maintaining the natural characteristics of the flat line sound good. Also be based on the content of the music and sound source characteristics to attenuate or enhance accordingly , but be sure to note that, regardless of cut or boost should be moderate and not too much, otherwise the sound will be unnatural and even metal sound. 8000Hz tone above the highest area, this band has an important contribution to the tone , but also part of our regulatory objects timbre of the sound source can be combined with appropriate compensation.

The human ear is more sensitive to the tone of feeling , it can determine whether the direct sound realistic. If a deal sounds good, not only will sound monotonous , boring , but also people make musical instruments or singing a serious distortion , and therefore can not ignore the importance of sound timbre processing that compensation . Specific to the singers , the male voice , the voice of the majority of people relatively low, the lack of treble, in order to improve the clarity of the concert , and can be extremely frequency of 3kHz to compensate ; For the female , it seemed too much treble and sound hair " sharp" , for the sound loud and clear, not too harsh , and can compensate for 400Hz frequency components .

Thus, the principles of sound compensation should be flat line , proportionate and necessary . If the sound is real and natural , then, to maintain a flat line , and once the necessary adjustments must be modest . Regardless of what bands are required to compensate for combining content and sound effects , but also with the volume adjusted to achieve a balanced overall .

In fact , we can know that we have conducted sound compensation are in fact mainly revolves around the figure of equilibrium ( ie, channel equalization ) to carry out.

2 volume adjustment
Volume adjustment has two purposes : First, to control the dynamic range of the sound signal , the second is to adjust the ratio between the brightest signal . Volume adjustment need be combined with sound compensation , because the volume and frequency are inseparable. Therefore, before tuning , the ratio between the dynamic level, frequency characteristics, and live acoustic signals between each signal is to be clear in the chest , you need to listen several times , repeated testing , while also taking into account future playback the effects of various conditions and playback . Volume Adjustment to the following principles .

( 1 ) Dynamic range control
We know that the dynamic range of the sizes of various sound sources , symphony orchestra with up to 100 dB dynamic range , the sound of the language , but only about 40 db . Mixer to control the dynamic range of about 60 db . Dynamic sound signal can be divided into strong signal , medium signal , weak signal categories. The highest level of strong signals to control the volume at 0 db at the table, to control moderate signal at -10 dB , weak signals will have to be controlled between -40 to -20 dB. Note that the weak signal is higher than the noise level of at least 6 db , we can increase the level of a weak signal to noise ratio , signal level , the higher the SNR , the more noise reduction. You know, the noise is the recording and playback of predators , an important task for us is noise tuning , and the best means of noise reduction by improving the signal level is to improve the signal to noise ratio .

Volume balance

( 2 ) signals from various quarters

The actual performance , we certainly come into contact with multiple input signal, then , we must pay attention to the volume balance . Adjust the volume balance is the ratio between the brightest sound signal , the size of the sound level does not depend entirely on the level , it is closely related with the volume balance . For example, when singers , how to adjust the microphone volume and the proportion of good singing musical accompaniment between them ? A nice song , it should be 40% of the accompaniment of music , singing voice accounted for 60 %, if the singer sounds good, may be appropriate to reduce the weight of some musical accompaniment to highlight the singer's voice ; If the singer of this song not very familiar with the melody , easy to sing out of tune , not close shot , in order to cover up these shortcomings, this time may be appropriate to increase the number of components of musical accompaniment . However, when specific operations, should be careful not to adjust the microphone volume too big , not much higher than the volume of the accompaniment music concerts . The results appear accompaniment sound is too weak, most of the time only to hear the singer 's voice , like a man in there cappella , losing the atmosphere of a live concert ; too , but do not let the accompaniment sound , the sound too , will " drown " the singer's voice, sounds like just a band playing music, can not see the singer's taste.

3 sound volume adjustment and compensation

* Volume hours Note enhance low and high frequency ; appropriate frequency to enhance the volume is large, in order to enhance the brightness of the sound .

* Tuning to voice -based. Before the song appeared , the accompaniment gradually lowered down to highlight the song . Should attenuate low-frequency 3 dB ~ 5dB, high frequency attenuation 7kHz above should 3dB, near the low frequency 200Hz to enhance intensify , 2kHz ~ 4kHz enhance 3dB ~ 6dB can clearly feel the song and bright. For disco or rock will have to pay attention to more substantial enhance low-frequency (40 Hz ~ 100Hz) and high frequency (7kHz ~ 20kHz).  

* Enhance the bass when compensation must not be shoved spin button , so as to avoid excessive damage to the power output of the amplifier and speakers. Adjust the equalizer same is true of the low-frequency requirements . asp.rar

Four conclusions
Most of our members are halfway decent tuning , learning on the one hand the lack of a comprehensive system of tuning theory, on the other hand the lack of proper and sufficient practice , and thus should have a perfect tune mixer is unrealistic and impossible the . But as long as we strengthen theoretical study and practice, the most basic and most important tuning tips we can grasp , and we all work together .

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