The wireless microphone system is also called wireless microphone, or wireless microphone, or microphone wireless. Microphone wireless is an audio equipment that transmits sound signals and consists of a transmitter and a receiver.
The wireless microphone system is also called wireless microphone, or wireless microphone, or wireless microphone. Microphone wireless is an audio equipment that transmits sound signals and consists of a transmitter and a receiver.
The working principle of the wireless microphone system: The transmitter is powered by a battery, and the microphone converts the sound into an audio electric signal. After being processed by the internal circuit, the radio wave containing the audio information is emitted into the surrounding space.
The receiver is generally powered by the mains. The receiving antenna receives the radio waves from the transmitter, processes the internal circuit, extracts the audio signal, and sends it to the sound reinforcement system through the output signal line to complete the wireless transmission of the audio signal. A receiver usually contains 1, 2 or 4 sets of receiving circuits, which receive signals from 1, 2, or 4 or 8 wireless microphones respectively, which are called "one for one" and "one for one". Two" or "one with four" and one with eight models. Among them, one with two models is the most common.
The wireless microphone is essentially a one-way wireless communication system.
As the name suggests, professional microphones are different from ordinary civilian microphones.
In terms of types, there are mainly condenser microphones (including electrets, also called pre-polarization), dynamic microphones, ribbon microphones.........
From the functional group, there are three categories:
First, the microphones used in performances mainly use dynamic microphones and condenser microphones (mainly selected according to the use occasion and requirements).
Second, microphones for recording mainly use condenser microphones and ribbon microphones. Condenser microphones for recording do not include electret microphones.
Third, conference microphones mainly use electrets and a small amount of dynamic microphones.
The microphones sold on the market are mainly divided into two categories: One is the dynamic microphone. Its main feature is good sound quality, no power supply, but relatively high price. Another type of microphone is an electret microphone. It is characterized by durability and high sensitivity. It needs 1.5～3V power supply, and the sound quality is worse than that of dynamic microphones of the same price. But its price is relatively low, suitable for broadcasting microphone.
As a home microphone, it is best to choose a dynamic type, because its sound quality is better than other types, it can truly reproduce human voices, and it is not easy to generate self-excited whistling with audio equipment in a high-volume environment, and damage the treble in the speaker speaker. Genuine goods are usually packaged exquisitely and the design is also very beautiful. The microphone should feel heavy and comfortable in the hand, and the screen cover should be free of burrs or damage. There should be a trademark brand consistent with the microphone on the microphone line.
After choosing a product that you are more satisfied with, you can use a high-quality imported high-fidelity audio to test the machine. When testing the machine, plug the microphone into the audio headphone jack, turn the volume to the minimum, use the random CD player or VCD player to play the genuine music tape, turn the volume down, and turn on the microphone switch. At this time, you will find that the microphone becomes one With a small speaker, you can experiment with different microphones and choose the one with the best sound quality.
Finally, check its workmanship, that is, shake the microphone head, it should not be loose, let alone be separated from the microphone. After connecting to the microphone jack of the power amplifier, the microphone should not have a "click" sound when switching, and there should be no noise when the switch is pressed. After the above careful selection, if the microphone can pass, such a microphone is undoubtedly excellent.
Condenser microphones have two metal plates, one of which is coated with an electret film (mostly polyperfluoroethylene propylene) and grounded, the other plate is connected to the gate of the field effect transistor, the gate and the source A diode is connected between the poles. When the electret diaphragm itself is charged, the electric quantity of the surface charge is Q, and the electric capacity between the plates is C, the ground voltage U=Q/C will be generated on the pole head, when it is subjected to vibration or air flow friction , Due to vibration changes the distance between the two plates, that is, the capacitance C changes, but the power Q does not change, it will cause a voltage change. The magnitude of the voltage change reflects the strength of the external sound pressure, and the voltage change frequency reflects The frequency of the outside sound, this is the working principle of electret microphone.
The diaphragms of condenser microphones are mostly polyperfluoroethylene propylene, which has good humidity performance, produces more surface charges and is less affected by humidity. Because this kind of microphone is also a capacitive structure, the signal has a large internal resistance. In order to extract and amplify the voltage signal generated by the sound, the output terminal must also use a field effect transistor.