Many people may think that just picking up the microphone and being able to talk, it is not the case. If you want to make the microphone emit high-quality sound, its use is also exquisite. Now let's learn about the basic use of the microphone with the editor of teanma. Bar.
The choice of microphone should be based on the occasion of use and the requirements for sound quality, combined with the characteristics of various microphones, and comprehensive consideration should be given to the selection. For example, high-quality recording and broadcasting mainly require good sound quality. Condenser microphones, ribbon microphones or high-quality moving coil microphones should be used; for general sound reinforcement, ordinary moving coil microphones can be used; when the speaker's position is irregular When moving or speaking, there is a large distance from the amplifier, such as karaoke singing, a unidirectional, low-sensitivity microphone should be used to reduce noise interference. The use of condenser microphones requires phantom power supply. Generally, the power supply voltage is stated in the technical parameters of the microphone. It is necessary to select a phantom power supply with an appropriate voltage. The mixer is generally equipped with 48V phantom power supply.
The choice of microphone should be based on the occasion of use and the requirements for sound quality, combined with the characteristics of various microphones, and comprehensive consideration should be given to the selection. For example, high-quality recording and broadcasting mainly require good sound quality. Condenser microphones, ribbon microphones or high-quality moving coil microphones should be used. For karaoke performances, unidirectional, low-sensitivity microphones should be used.
It should also be noted in use:
1. Impedance matching
When using a microphone, the output impedance of the microphone is the same as the input impedance of the amplifier, which is a better match. If the mismatch ratio is more than 3:1, the transmission effect will be affected. For example, when a 50Ω microphone is connected to an amplifier with an input impedance of 150Ω, although the output can increase by nearly 7Db, the high and low frequencies will suffer significant loss.
2. Connecting line
The output voltage of the microphone is very low. In order to avoid loss and interference, the connecting wire must be as short as possible. For high-quality microphones, you should choose a twisted-core metal shielded wire. Generally, a single-core metal shielded wire can be used for a microphone. The length of the high-impedance microphone transmission line should not exceed 5 meters, otherwise the treble will be significantly lost. The low-impedance microphone connection can be extended to 30m-50m.
3. Working distance and proximity effect
Generally, the working distance between the microphone and the mouth is 750px-1000px. If the distance is too far, the reverberation will increase and the noise will increase relatively; if the working distance is too close, the signal will be distorted due to the strong signal and the low-frequency sound will be affected. The clarity of the language. This is because the directional microphone has a "close-talking effect", that is, the low-frequency sound will be significantly improved when speaking at a close distance. However, sometimes singers deliberately use the "near-talking effect?" to make the singing effect more beautiful and pleasant.
4. The angle between the sound source and the microphone
Each microphone has its effective angle. Generally, the sound source should be aligned with the center line of the microphone. The greater the deflection angle between the two, the greater the treble loss. Sometimes when the microphone is used, there is a "rumble" sound. At this time, you can reduce it by deflecting the microphone to a certain angle.
5. Microphone position and height
When amplifying the sound, do not place the microphone close to the speaker or aim at the speaker first, otherwise it will cause howling.
The height of the microphone should be placed according to the height of the sound source. If one person speaks or several people sing, the height of the microphone should be the same as the singer's mouth; when there are many people, the microphone should be placed at an average height, and the singer should be appropriately deployed With the accompaniment and the position of the various instruments in the team, do not make the loudness too loud, light or too light, and make all the sounds within the effective angle of the microphone. If there is a lead singer or lead singer, a dedicated microphone should be placed when necessary.
When several microphones are required to be used at the same time, the parallel connection method can be adopted, but the phase problem of several microphones must be paid attention to. Only when the phases are the same can they be connected in parallel, otherwise they will interfere with each other, reducing the output and causing distortion. Microphones of different models and different impedances should not be used in parallel, because high-impedance microphones "short-circuit", causing the output voltage to drop to a very low level. Under normal circumstances, microphones are used directly in parallel, and the effect is not as good as a single microphone.
If several microphones are used for a person's speech at the same time, instead of separating several places for different purposes, it is better to choose the same type of microphone. Otherwise, the pitch of the speech will be changed due to the speaker's walking or changing angle.
The sound reinforcement effect of this kind of collaboration is very good, and the sound quality is relatively stable, but the teacher must be pointed at the microphone to have the sound reinforcement effect. The scope of teachers' activities is very small, which is not conducive to the communication between teachers and students. Therefore, unless they are in large lecture-style classrooms, they are rarely equipped.
Directly connected to the power amplifier through the audio cable, the teacher's activity range is affected by the length of the microphone cable, and extends to the entire platform, and the effect of sound amplification is better
In principle, there is no position restriction in the classroom. During classroom teaching, it can be used not only by the teacher, but also when the students answer questions.
But the channel should be set up to avoid crosstalk with the next class.
When in use, there will be a blind sound zone, and the sound quality is easily affected by the current
Including head-mounted and lavalier styles. The advantage is that it frees the hands of the teacher, but the disadvantage is that it is not very good-looking
Precautions for use
Microphone volume adjustment
You must pay attention to the adjustment of the volume. After all, there are many classrooms in the school, and too much sound will affect the teaching effect of the next class.
Secondly, high volume is easy to make students tired, which is not conducive to the healthy growth of children.
The choice of microphone power supply
The power consumption of school microphones is relatively large, and the use of disposable power is costly and not environmentally friendly. Therefore, it is recommended to use a rechargeable power supply.
Daily management of the microphone
Each class should assign someone to take charge of cleaning and tidying up the microphone.
Note: Turn off the power of the microphone in time to avoid power consumption and affect future use.
The microphone should be protected from knocking or falling during use. It is not advisable to test the microphone by blowing or tapping, otherwise the microphone will be easily damaged.
When the microphone is used outdoors or when recording voices, a windshield should be used to avoid recording the "pop" sound of the wind. The windshield also prevents dust from contaminating the microphone.
Note when using wireless microphones:
(1) Choose the location of the receiver to avoid the "dead point".
(2) When receiving, adjust the angle of the receiving antenna, adjust the frequency, and adjust the volume to make it in a better state.
(3) The antenna of the wireless microphone should hang down naturally, out of the clothes.
(4) Prevent the battery's polarity from being reversed, and take out the battery in time after use.
Some microphones (such as electret condenser microphones, wireless microphones) are battery-powered. If the voltage drops, the sensitivity will decrease and the distortion will increase. Therefore, when the sound becomes poor, check the battery voltage, turn off the power switch when the microphone is not in use, and remove the battery when it is not used for a long time.