The working principle of wireless microphone:
The wireless microphone is mainly composed of a transmitting part and a receiving part. The transmitting part is powered by a battery, and the microphone will dynamically convert it into an audio signal. After being processed by internal circuits, radio waves containing audio information will be transmitted to the surrounding space. The receiving part is generally powered by city power, and the radio waves announced by the transmitting part are received by the receiving antenna. After processing by the internal circuit, the audio signal is extracted and sent to the sound reinforcement system through the output signal line, and then the wireless transmission of the audio signal is completed.
After understanding its working principle, let's take a look at the precautions for using wireless microphones.
1. Induction hardening
When using a wireless microphone, the output impedance of the wireless microphone is the same as the input impedance of the amplifier. If the mismatch ratio is above 3: 1, the transmission effect will be affected. For example, when a 50ω wireless microphone is connected to an amplifier with an input impedance of 150ω, although the output can increase by nearly 7Db, the high-frequency and low-frequency dynamic characteristics will be significantly lost.
2. Working interval and near language effect
The working distance between the wireless microphone and the mouth is generally 750 px-1000 px. If the interval is too far, the reverberation will increase, and the noise will increase relatively. If the operation interval is too close, the signal will be distorted because it is too strong, and low-frequency sound will affect the intelligibility of the speech. This is due to the "near sound response" of the directional microphone, that is, when playing in a short time interval, the low-frequency sound will be significantly advanced. However, sometimes singers will deliberately use "near sound effects" to make their singing function more beautiful.
3. The point of view of sound source and wireless microphone
Each wireless microphone has its own useful point of view. Generally speaking, the sound source should be aligned with the center line of the wireless microphone. The greater the deviation angle, the greater the treble loss. Sometimes, when using a wireless microphone, it can be alleviated by deflecting it from a specific angle.
4. The direction and height of the wireless microphone
When amplifying the sound, do not put the wireless microphone close to or aim at the speaker first, otherwise it will cause howling.
The height of the wireless microphone should be determined according to the height of the sound source. Suppose one person speaks or several people sing, the height of the wireless microphone should be the same as the singer’s mouth; when there are many people, the wireless microphone should be placed at a uniform height, and the positions of the singer, accompanist, and various instruments in the team should be properly distributed. Don't be too loud or too soft, and all actions must be within the useful point of view of the wireless microphone.
When in use, prevent the wireless microphone from knocking or dropping. It is not recommended to test the microphone by blowing or tapping, otherwise it is easy to damage the wireless microphone.
When using a wireless microphone or recording voice outdoors, use a windshield to prevent the "pop" sound from entering the wind. The windshield also prevents dust from contaminating the wireless microphone.
5. Take out the battery in time when not in use
The wireless microphone is powered by a battery. If the voltage drops, sensitivity will decrease and distortion will increase. Therefore, when the dynamics deteriorate, check the battery voltage, turn off the power switch when the wireless microphone is not in use, and remove the battery when it is not in use for a long time.