Six skills in using professional mixer

Professional mixer uses six skills

There are many ways to describe the mixer, and the most appropriate way is to regard the mixer as the heart of a sound system. The blood circulation of this heart directly affects the stability of the whole system. So as Andhadhun, how do you master the skills of tuning? The following are six skills that I collected and integrated for you to use the professional mixer, hoping to help you.

1

signal input of the mixer

The input signal of the mixer can be roughly divided into two types: low-impedance microphone signal input and high-impedance line signal input. Each input can be regarded as a water pipe, that is, it is assumed that a mixer has multiple signal inputs, just like the water from multiple water pipes flows into the mixer for processing. The author can regard the difference between low resistance and high resistance as the difference of water pressure or running water speed. For example, the high-resistance input level is just like the high water pressure and the rapid water flow, so it is appropriate to input it directly into the pool of the mixer, and there is no need to add any link in the center to adjust the water pressure and water flow rate; However, the level of low-resistance input is low, just as the water pressure is very low and the water flow is very slow, so it is not suitable to input it directly into the mixing table. Therefore, the author needs to add a water pump to the flood pool to increase the low-resistance water pressure and speed up the water flow, so special circuit amplifiers are built into the low-resistance input channels of the mixing table to expand the low level to a suitable level. We should have a good understanding of using the characteristics of water to describe low-resistance signals and high-resistance signals.

2

Adjustment of gain

To input the sound source in the mixer, we must first distinguish whether it is low resistance or high resistance, and then connect it to the mixer accurately with a standard signal line. Assuming that every sound source should achieve perfect sound quality, the author needs careful adjustment. The gain of each input channel of the mixer is very important, but many sound engineers simply regard the gain as a volume knob, which is a big mistake. Originally, the gain is mainly used to control the dynamic scale of the input signal. Usually, when the gain is adjusted to the maximum distortion, it is the maximum useful dynamic scale and the best working condition. It is difficult to understand the contrast, so it is still described by water: the input channel and input line of the mixer will have a fundamental background noise, which is like sediment in the river bottom and cannot be eliminated. We know that when the river is not deep, the moving water is under the sediment, so the water quality must be poor. So that is to say, assuming that the dynamic scale of gain adjustment is lacking, the sound source signal is like running water under the sediment, and the background noise will pop out, and the sound quality must be poor at this time; On the contrary, when the river is relatively deep, the moving water is relatively clear and the water quality must be excellent, that is to say, the dynamic scale of gain adjustment is large and the contrast is reasonable, so the sound quality must be excellent; Of course, assuming that the water potential is huge, even the dam has burst and the bottom of the river has been overturned, this is equivalent to the distortion of the level signal. At this time, there is no sound quality at all, and it will also damage the equipment, so it is not that the greater the gain, the better. It is necessary to have a degree and appropriateness. I want to describe the function of gain in this way, even beginners of audio should be able to understand it.

3

Adjustment of equalization group

When the gain is adjusted, it is usually necessary to adjust the equalization group of the mixer channel next, and the adjustment order should be from the low voice to the high voice. Because as long as the fundamental sound of the sound is ensured, the repeated overtones with good sound can be ensured. We have no doubt about the fundamental adjustment. Here, the author only talks about a few tricks.

nowadays, the equalization group of professional mixing consoles usually has frequency selection adjustment, which many sound engineers can't use sensitively. It's difficult to say all the details. Some things depend on their own understanding, and the author can only briefly talk about it: for example, when playing disco music, I can't feel the low sound intensity. We can choose the low sound frequency of the equalization group of disco music venues at around 2Hz, and then use the adjustment knob to improve it moderately, so the low sound intensity comes out; For example, when a female singer's dentition is remarkable, the authors can choose the high frequency at around 6Hz, and then use the adjusting knob to moderately attenuate it, so that the dentition can be appropriately reduced. Assuming that the application is sensitive, we can also use the frequency selection function of the equalization group to suppress the acoustic response. For example, there is usually a * * vibration peak around 3Hz in the ballroom, and usually the acoustic response occurs briefly at this frequency. The author can select the frequency of the microphone input channel around 3Hz, and then use the adjustment knob to moderately attenuate it, so that the acoustic response can be effectively reduced. Of course, the frequency of acoustic response in each sound field is different, but no matter what frequency the acoustic response is, it can be simply controlled in this way. Of course, this demand is sensitive to experience. Moreover, it is necessary to adjust the sound field and prevent the acoustic response perfectly by using a professional multi-stage equalizer or reaction suppressor, which will be introduced in detail in the future articles on peripheral systems. There is always a mixer, and it is the balanced group of the mixer that the sound engineer often sets out to adjust. It is often seen that some sound engineers only know how to push and pull the volume fader, but they are too lazy or ignorant to adjust the balance knob. Originally, they were using the side. It can be said that we need to adjust the mixer at all times. Take a song as an example: When a singer walks onto the stage to introduce his own performance, we need to turn down the microphone in a low voice, adjust the reverberation to a moderate level or turn it off, so as to ensure the clarity of speech; When the music starts and the singer starts to sing, the authors need to increase the microphone in a low voice, otherwise the sound will appear thin and the reverberation volume will be increased to an appropriate level; In other singing, in order to prevent the music treble from grabbing the microphone treble, the author can slightly attenuate the music treble; However, when the song is played intermittently, the attention of the audience will shift from the singer to the music, so at this moment, the author needs to increase the treble of the music and turn up the music together, so that the music will be excellent and natural, otherwise it will look too dull without change. And at this moment, we have to turn down the reverberation volume, so that even if the singer suddenly speaks during the intermission, there will be no very mixed reverberation; When the intermission of a song is over and the next song is sung, the authors should turn down the music, attenuate the high notes, turn up the microphone and reverb the volume. At the climax of the final singing, the authors also need to turn up the microphone volume, and then turn up the music volume from small to large in an instant to make a perfect, shocking and magnificent climax to end it. Of course, not all songs are suitable for this operation, so what the sound engineer needs is sensitivity. I think it's really necessary to express every function of the mixer in writing, and it may be necessary to write a thick book, and the function is not necessarily significant. Here, the space of the author is limited. I just want to start with my experience in using the mixer for many years, and I have to rely on my own efforts and study in detail.

4

Adjustment of AUX

The adjustment knobs on the mixer are usually the most balanced groups, and then it is. Because of its auxiliary nature, many sound engineers did not attach importance to it, nor did they fully understand its function. I remember that when I was studying in Beijing Radio and Television Department in 1997, I spoke to this AUX teacher for two days, but many students were still at a loss. In the end, the author really couldn't help it. It took two minutes to solve their two-day confusion. After understanding, many students lamented that this AUX was so simple! Of course, it can't be said that the author scored higher than the teacher at that time, only the author used an image analogy: the author said that every input channel of the mixer was like a big tap water pipe, and after the water came in, the two water mains A and B were basically distributed: a road A water mains is: the volume fader of this channel of the mixer was sent out after grouping, and we all knew it when the channel volume fader was mentioned; The other B-way water main is the AUX group, but the difference is that some AUX in a mixer can be divided into multiple channels. Assuming that a mixer has four AUX channels, it is like dividing the AUX group's B-way water main into four small water pipes and then flowing them out. It has the same principle as the following fader, except that most AUX volume switches are controlled by knobs, while the channel volume switches in the same channel are controlled by faders, just like the same torrent. Therefore, the authors can't just look at the appearance differences of things, because their functions are quite different. Seeing that most beginners in audio here should know enough, the most important thing is to know that the knob of AUX has the same function as the volume fader of the mixer. Next, we will talk about the detailed application method of the AUX group: AUX is usually used to connect the voice speaker at most, and the author sends the processed sound to the speaker with the corresponding AUX switch, and then flows back to the tuner after processing. This is basic knowledge, and most sound engineers should know it; The AUX of a large mixer usually has a fader before/after conversion. When it is set in front of the fader, the total volume fader below this channel can't control the volume of this AUX. On the contrary, it is controlled by the total volume of this channel. Other functions of AUX are for monitoring or recording. Another convenient use is that we can also use AUX to control the low volume of a sound system, so we can turn up the corresponding AUX if we need more low-volume channels, but we don't need high-volume sound sources, such as microphones, so the corresponding AUX in their locations can turn down the volume, otherwise the low-volume sound response will occur briefly. Generally, if you understand the principle of AUX, you will be able to bypass it, and I won't say much here.

5

Audio-visual balance adjustment

Acousticians usually know the audio-visual of the mixer, but many of them are dull. For example, when a two-channel stereo sound signal is input to the mixer, most of them will turn the audio-visual knobs of these two channels to the left and right, thinking that this is it? Stereo? In this case, the sound coming out of these two channels will appear very floating, and the center will be weak and weak; Suppose you hit the audio-visual knob to the center, you will feel that the music sounds are all on your head, which is very sad, and the width of the sound is not good; The best orientation is that the audio-visual knob of the left channel is turned to the 9 o'clock, and the audio-visual knob of the right channel is turned to the 15 o'clock. This kind of music is dynamic, wide in scale and good in strength and penetration. We can try it carefully, so I won't analyze the principle, and I only pay attention to practice. I don't want to say much about other aspects of audio-visual applications, which are all basic knowledge. What is usually thought to be the simplest thing is very messy when you think about it.

6

Some adjustments to the main outputs

Some of the main outputs of the mixer refer to the group volume and the total volume. For example, the authors can organize the band into 1-2 groups; Group the microphones into 3-4 groups; It is always convenient to control the low voice by the volume of 5-6 groups and the auxiliary speaker by the volume of 7-8 groups. Other groups can choose to output signals alone or cut the group signals into the main volume mixing control of the mixer. Others, such as channel faders, are very simple, but the volume faders should be controlled sensitively according to the situation of each input channel. Although this adjustment is simple, it is very important. The first thing is to pay attention to the input and output level signals of various signals, and there should be no serious distortion. ;