Wireless Microphone

Wireless microphone is a kind of sound equipment for transmitting sound signals, which is composed of transmitter and receiver, usually called wireless microphone system.
1. What is a wireless microphone?
The wireless microphone is composed of a plurality of portable transmitters (which can be packed in a pocket, and the output power is about 0.01W) and a centralized receiver, wherein each portable transmitter has a different working frequency, and the centralized receiver can simultaneously receive voice signals with different working frequencies sent by each portable transmitter. It is suitable for stage, platform and other occasions.

2. How Wireless Microphones Work?
The transmitting part of the wireless microphone is powered by the battery. The microphone converts the sound into audio electrical signals, and then transmits the radio waves containing audio information to the surrounding space after being processed by the internal circuit.

The receiving part of the wireless microphone is generally powered by the mains supply, the radio waves sent by the transmitting part are received by the receiving antenna, the audio signals are extracted through the processing of the internal circuit, and the audio signals are sent to the sound reinforcement system through the output signal line, thereby completing the wireless transmission of the audio signals.
 
3. Wireless Microphone Features:
The appearance is designed in accordance with ergonomics and aesthetics:
The tube body of the hand-held wireless microphone must have a size suitable for holding by the palm and a graceful shape. Generally, the traditional tube body is in the shape of a bamboo tube or a trapezoid, which not only has no aesthetic feeling, but also is not suitable for holding by the palm. Especially for users who are easy to sweat, it is not easy to hold tightly and slip off. The most suitable shape for holding is the double inner curve shape with a smaller diameter in the middle than at both ends, just like the waist of a woman, which is not only beautiful in shape, but also easy to hold.

Handheld microphones use an advanced hidden antenna design:
The biggest difference between man and monkey is that they don't have a tail. Early wireless microphones have an external antenna at the end, but advanced wireless microphones overcome the technical difficulties, no longer use the outdated external design, but use the most perfect hidden antenna design, so that wireless microphones have the advantages of easy to use, safe, beautiful and not broken.

To assemble a good sound head:
The quality of the sound head determines the first pass of the sound quality of the wireless microphone. There are two types of sound heads, the moving coil type and the capacitive type. The moving coil type uses a coil loaded on a diaphragm to convert sound energy into an electrical energy signal in a high-density magnetic field. There is a limit to the characteristics of the voice coil of this head. But basically the structure is simple, the price is cheap, and it is the most popular type of machine on the market. Condenser microphone is a kind of microphone with high technical level in electronics and structure. Its sound is directly converted into electric energy signal by using the change of capacitance between electrodes and ultra-thin gold-plated diaphragm. The most important feature of the advanced condenser microphone is that it can show excellent original sound quality. The high and low frequency response is very wide and flat, the sensitivity is very high, the directivity and dynamic range are large, the distortion rate is low, the volume is light and durable, and the touch noise is low. It is widely used in recording studios, professional stages, testing instruments and other professional equipment. The only drawback is the need to provide a bias (Phantom Power), but because the wireless microphone itself has a power supply, the condenser sound head is the best match for the wireless microphone, so that all the advantages can be brought into play on the wireless microphone. Taiwan MIPRO wireless microphone is the only product equipped with advanced capacitive sound head.

The microphone should have the advantages of low touch noise:
The touch noise caused by the friction between the handheld wireless microphone and the palm affects the normal sound quality. Especially, the wireless microphone itself has a sensitive preamplifier, which makes the touch noise more serious and becomes a technical bottleneck. Because the general wireless microphone has no professional design experience, and in order to reduce the manufacturing cost, it uses simple circuit, cheap sound head, poor suspension design and cheap tube surface treatment, so the poor sound quality can not overcome the significant touch noise of the microphone and degrade the original sound, so it chooses the high-quality wireless microphone. Special care must be taken to select features with excellent sound quality and ultra-low touch noise.

With the function of eliminating sound interruption or instability:
The signal transmitted by the wireless microphone is attracted and reflected by the surrounding environment, so that the signal received by the receiving antenna has a dead angle, and the output sound is interrupted or unstable, which is not allowed to occur especially in professional occasions. In order to solve this shortcoming, the most perfect effect can be obtained only by adopting the most advanced automatic signal selection receiving system. Generally, cheap dual-channel receivers popular in the market do not have the function of automatic signal selection and reception, and can not avoid the above shortcomings, so they can only be used in short-distance family karaoke occasions. In professional places or users who attach importance to sound quality, they must choose the type of automatic signal selection receiving system to meet the requirements of sound quality and obtain perfect performance.

It has the function of preventing loud noise caused by interference during standby:
Generally, the receiver has a Squelch Control function. When the power is turned on and there is no microphone signal input or the signal strength is lower than a certain signal-to-noise ratio, the Squelch Control circuit will turn off the output circuit, and the main receiver is completely muted to prevent noise output. When the microphone signal is turned on, the receiver immediately turns off the mute circuit and turns on the output circuit to allow the audio circuit to output the sound of the microphone. However, at the moment when the microphone power is turned on and off, or when the microphone signal is turned off, the signal interference exceeding the mute control intensity is occasionally encountered, and the receiver mute circuit will also be activated by these impact noise and interference noise to output loud noise. In order to solve this problem, the so-called "audio lock mute circuit" is added to the advanced models to suppress it. The principle is to add a fixed ultra-audio modulation signal into the transmission signal of the microphone, and at the same time, a discriminator is installed inside the receiver, so that the receiver can start the output circuit only when it receives the microphone signal containing the fixed ultra-audio modulation signal, so as to achieve the function of preventing other signals or noise interference. In order to protect your valuable audio system from being damaged by loud noise, you must choose a model with tone code locking mute function.

It has the function of multi-channel use without interference:
The biggest technical bottleneck in the use of wireless microphones is the problem of signal interference, especially the more frequencies used, the more serious the problem of interference. Therefore, in the case of using multiple wireless microphones at the same time in the same place, to avoid interference, in addition to carefully selecting frequencies that do not interfere with each other physically and avoiding adjacent external signal interference, the receiver should have excellent selectivity. The transmitted and received radiated harmonics must be filtered to a very clean level in order to avoid interference between the signals. The general VHF band receiver can use about 12 frequencies at the same time, which is already very good, while Taiwan's MIPRO products can use 24 frequencies at the same time without interference, and even in a specific environment, through special design and arrangement, more frequencies can be used at the time.

To solve the problem of simultaneous use of multiple channels and to avoid interference, a multi-channel series model with digital locking that can change the frequency should be selected:
The traditional wireless microphone system is designed to lock the fixed frequency with quartz. In the case of multi-channel use or strong signal interference, this model cannot arbitrarily change the desired frequency, but must be replaced. In order to solve this problem, the advanced model adopts PLL Synthesized method. Dozens of frequencies are pre-stored in the transmitter and receiver for the user to change at will. Although the cost of this advanced design is high, it provides very convenient functions for distributors and users, and completely solves the above problem. MIPRO, a company in Taiwan, has been able to mass-produce this complete series of products with the most advanced design and the most reasonable price.

To avoid frequency "traffic jam" or signal interference, products with digital locking UHF channel system should be selected:
As too many wireless microphones in the VHF200MHz frequency band are used, the problems of mutual interference of signals and noise interference of various electrical appliances are becoming more and more serious. Therefore, the frequency used by professional wireless microphones is gradually increased to the UHF frequency band of 800MHz, and the PLL phase locking circuit is adopted to preset the design that multiple channels can be switched at will. Avoid the interference of other signals and the noise of general electrical appliances to obtain the best use effect. Because the circuit design of UHF band is more complex and the high-frequency parts used are more precise, the price is still higher and the manufacturers of mass production are fewer. However, UHF models are the best choice for professional quality and will gradually become a popular trend in the future.