Due to the advancement of today’s radio communication technology, the quality and functions of wireless microphone products have been relatively improved to reach a mature and practical field. We will provide you with newer technical elements related to the design of this product, allowing consumers to purchase this product. Before this product, I can judge how to buy a high-quality product with great value. At the same time, it also provides manufacturers with reference to discuss how to produce and sell advanced products that consumers are satisfied with.
One. Understand the types of wireless microphones
Before purchasing a product, you should first have a basic concept of the product category before you can choose the model that suits your needs. According to different definitions, the types of wireless microphones can be divided into many different types.
1. Distinguish according to the transmitting frequency:
a. FM wireless microphone: commonly known as FM refers to the FM 88-108MHz international FM radio frequency band. Early consumer wireless microphones used FM radio to receive. The system was simple and low in cost. However, due to the effect of use, it failed to meet the requirements of professional quality. At present, it can only be used as a toy for children or students.
b. VHF wireless microphone: It is divided into two types, low frequency and high frequency. The former uses the VHF50MHz frequency band. Because of the low frequency, the antenna length is too long, and it is most susceptible to interference from various electrical clutter. Therefore, this type of Products have been replaced by high frequency bands and gradually disappeared from the market. The latter uses the VHF200MHz frequency band. Because of the higher frequency, the antenna is shorter, and it can even be designed as a hidden antenna, which is convenient, safe and beautiful. The clutter interference of the receiver is greatly reduced, the circuit design is extremely mature, and the parts are popular at a price. Low cost, so it has become a popular model on the market today.
2. Distinguish according to the receiving method:
a. True diversity receiving wireless microphone system (True diversity receiving wireless system): Due to the physical phenomenon of "dead-point" (dead-point) in the radio waves, the sound output of the receiver will produce intermittent or unstable shortcomings. To solve this defect, professional models must adopt the "Automatic Switching Diversity Receiving" method with dual antennas and dual tuners to improve.
b. Non-diversity receiving wireless microphone system (Non-diversity receiving wireless system): Due to the complicated and precise circuit design of the above models, it is difficult to assemble, and the cost is high. Generally, low-cost models do not adopt the design of automatic selection. , So it is impossible to eliminate the shortcomings of sound interruption caused by wireless microphones in use. Of course, this type of machine cannot meet the basic requirements for professional use.
.Different according to the mode of oscillation:
a. Qualtz locked model: It uses a quartz oscillator to generate a fine and stable fixed frequency for transmitting and receiving. The circuit is simple and the cost is low. It is the standard circuit design of today's wireless microphones. This type of microphone and receiver can only be paired with a single frequency, and the frequency cannot be changed or adjusted.
b. PLL Synthesized model: In order to prevent the wireless microphone from encountering interference from other signals and cannot be used during use, or to use multiple microphones at the same time, it is necessary to change the channel conveniently and quickly at any time, so The circuit design of PLL is adopted to meet the requirements of this function.
4. Distinguish according to the number of receiver channels:
a. Single-channel model: Only one channel of non-auto-selection or automatic-selection receiver is installed in a receiver chassis. The former has almost no market in Taiwan, but the export market is cheaper because of its lower price. Big color goods). The latter is easy to use and stable in characteristics, so it is suitable for multi-channel simultaneous use in professional situations to avoid signal interference.
b. Dual-channel model: In the case of a receiver, two-channel non-automatic selection or automatic selection receivers are equipped to make full use of the space of the case and reduce costs. The former is the so-called "Asian fighter" model, because of its simple design, it has become the main model for mass-produced low-priced manufacturers. The latter is not easy to deal with internal interference and antenna mixing and matching because of its complicated mechanism and circuit. It is only available for a few manufacturers that produce professional models.
c. Multi-channel model: In the case of a receiver, receivers with more than four channels are assembled, and most of them adopt the mechanical design of modular receiving modules. It is mainly suitable for the use occasions of rack-mounted professional models.
two. The choice between price and quality
Recently, some smaller manufacturers, in order to win orders, are not committed to the development of more advanced models, but to produce cheaper models to attract consumers. As the saying goes: "You get what you pay for". Consumers often choose low-quality products because they are greedy for a little bit cheaper prices. Some consumers are either too superstitious or misled by manufacturers' false advertisements. How to choose a model with excellent value for money, first respond to the quality positioning required by oneself, and further understand the principles of how to evaluate the quality of wireless microphones, in order to choose a truly satisfactory product.
three. The technical background of the manufacturer determines the quality of the product
Wireless microphone products are products designed by combining audio and wireless communication technologies. They are completely different from the technology and equipment for manufacturing wired microphones. Therefore, wired microphone manufacturers that also manufacture "microphones" may not be able to manufacture wireless microphones and wireless communication products. Manufacturers may not be able to manufacture good wireless microphones. Only manufacturers with long-term professional audio technology and wireless high-frequency technology background can manufacture good wireless microphones. Because wireless microphone products are quite different from other wired products, the use effect is very closely affected by environmental conditions. Therefore, a high-quality wireless microphone cannot be designed in the laboratory in the short term. After actual use in a variety of different environments, users will give back their gains and losses to the design engineer, and after continuous non-development and improvement, a truly beautiful product can be manufactured. Therefore, to choose a good wireless microphone product, one must choose a professional technical background and long-term manufacturing experience.
four. A good wireless microphone should have the following excellent characteristics:
1. Appearance design conforms to ergonomics and aesthetics: The tube body of a handheld wireless microphone must have a size suitable for hand-holding and a beautiful shape. Generally, the traditional tube body is in the shape of a bamboo tube or trapezoid, which is not only aesthetically lacking. It is also not suitable for hand-holding, especially for users who are prone to sweating, and it is less likely to be gripped and slipped off. The most suitable shape for hand grip is the double inner curve shape with a smaller middle diameter than the ends. It is like a Chinese Guanyin bottle or a woman's waist. It is not only beautiful in shape, but also easy to hold.
2. Hand-held microphones should use advanced hidden antenna design: the big difference between humans and monkeys is that they don’t have that tail. Earlier wireless microphones have an external antenna at the end, but advanced wireless microphones overcome technical difficulties and no longer use outdated external designs. Instead, they adopt the most beautiful hidden antenna design to make wireless microphones easy to use, It has the advantages of safety, beauty, and failure to break.
3. To assemble a good sound head:
The quality of the sound head determines the sound quality of the wireless microphone. There are two types of capsules, moving coil and capacitive. The moving coil uses a coil loaded on the vibrating membrane to convert sound energy into electrical energy signals in a high-density magnetic field. There are certain limits on the voice coil characteristics of this type of sound head. But the basic structure is simple, the price is cheap, and it is the most popular model on the market. Condenser microphone is a high-level microphone that combines electronics and structure. Its pronunciation is to use the change of the capacitance between the poles to directly convert the sound into an electrical energy signal with an ultra-thin gold-plated vibrating membrane. The main feature of high-quality condenser microphones is that they can display extremely clear original sound quality, high and low frequency response is very wide and flat, very high sensitivity, large directivity and dynamic range, small distortion, lightweight and drop-resistant, low touch noise, currently Widely used in professional equipment such as recording studios, professional stages, and testing instruments. The disadvantage is that it needs to provide a bias voltage (Phantom Power), but because the wireless microphone itself has a power supply, the condenser capsule is a better match for the wireless microphone, so that all the advantages can be used in the wireless microphone.
4. The microphone should have the superior characteristics of low touch noise:
The hand-held wireless microphone produces frictional touch noise between the palm of the hand when in use, which affects the normal sound quality. In particular, the wireless microphone itself has a sensitive preamplifier, which makes the performance of this touch noise more serious and becomes a technical bottleneck. . Generally, wireless microphones have no professional design experience, and in order to reduce manufacturing costs, they use simple circuits, low-cost capsules, poor suspension design and cheap tube surface treatment, so the sound quality is not clear and can not overcome the significant microphone Touch noise degrades the original sound. Therefore, when choosing a high-quality wireless microphone, you must pay special attention to choosing the characteristics of extremely clear sound quality and ultra-low touch noise.
5. It has the function of eliminating interruption or instability of sound:
The signal emitted by the wireless microphone is attracted and reflected by the surrounding environment, causing the signal received by the receiving antenna to have a blind angle, which makes the output sound interrupted or unstable. This phenomenon is not allowed especially in professional situations. occur. In order to solve this shortcoming, the best result can be obtained only by adopting a more advanced automatic selection receiving system. Generally, the popular low-cost dual-channel receivers on the market do not have this automatic selection receiving function, and the above shortcomings cannot be avoided, so they can only be used in short-distance home karaoke occasions. In professional places or users who value sound quality, they must choose the model of the automatic selection receiving system to meet the sound quality requirements and get a good performance.
6. It has the function of preventing loud noises caused by interference during standby:
Most receivers generally have a mute control function (Squelch Control). 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 mute control circuit closes the output circuit, and the main receiver is completely muted to prevent noise Output. When the microphone signal is turned on, the receiver immediately activates the mute circuit, allowing the audio circuit to output the microphone sound. But when the microphone power is turned on and off, or when the microphone signal is turned off, occasionally encounter signal interference that exceeds the mute control strength. The receiver mute circuit will also be activated by these impact noises and interference noises to output loud noises. In order to solve this deficiency, the so-called "audio lock mute circuit" is installed in high-quality models to suppress it. The principle is to add a fixed super audio modulation signal to the transmitter signal of the microphone: at the same time, a discriminator is also installed inside the receiver, so the receiver must receive the microphone signal containing this fixed super audio modulation signal The output circuit can be activated only when it is time to achieve the function of preventing interference from other signals or noise. In order to protect your valuable audio system from being damaged by loud noises, you must choose a model with a sound code lock and mute function.
7. With multi-channel non-interference function:
The larger technical bottleneck of the use of wireless microphones is the problem of signal interference, especially the more frequencies used, the more serious the interference problem. Therefore, when multiple wireless microphones are used at the same place at the same time, interference should be avoided, in addition to careful selection In addition to physically non-interfering frequencies and avoiding adjacent external signal interference, the receiver must have excellent selectivity, and the emitted and received radiated harmonics must be filtered to a very clean level to avoid signal interference. Generally, a receiver in the VHF band can be used for 12 frequencies at the same time, which is already very good.
8. To solve the problem of simultaneous use of multiple channels and avoid interference, a multi-channel series model with digital lock can be used to change the frequency: the traditional wireless microphone system uses a quartz lock fixed frequency design. This model is used in occasions where multiple channels are required. Or in the case of strong signal interference, the frequency you want to use cannot be changed arbitrarily, but the whole set must be replaced. In order to solve this deficiency, advanced models adopt phase-locked frequency synthesis (PLL Synthesized). Dozens of frequencies are pre-stored in the transmitter and receiver to allow users to change arbitrarily, although the cost of this advanced design is higher. , But it provides a very convenient function for distributors and users, and completely solves the above-mentioned deficiencies.
9. To avoid frequency "traffic jams" or signal interference, products with digital lock UHF channel system should be used: Due to the excessive use of wireless microphones in the VHF200MHz frequency band, the problems of mutual signal interference and various electrical noise interference are becoming more and more serious. Therefore, the frequency used by professional-grade wireless microphones has been gradually increased to 800MHz UHF frequency band, and adopts PLL phase lock circuit, preset multi-channel design that can be switched arbitrarily, avoiding interference from other signals and general electrical noise, and obtaining better results. . Because the circuit design of UHF frequency band is more complicated and the high-frequency parts used are also more precise, the current price is still high, and there are fewer mass-produced manufacturers. However, UHF models are the best choice for professional quality and will gradually become the future Popular trend.
10. Products with high-quality certification and passing the inspection of telecommunications regulations: High-quality wireless microphone products must be manufactured in factories that have passed high-quality certification, and they must also be certified by national radio laws and regulations before they can be sold and used legally. Consumers should choose certified products to use, so that the quality can be guaranteed.
Fives. Data collection and evaluation:
The most basic sources of information for purchasing products are catalogs and magazine advertisements provided by manufacturers. However, generally small-scale manufacturers with incomplete equipment cannot provide correct values at all, so consumers cannot understand, analyze and compare from catalogs. Some manufacturers even use catalogs and advertisements to exaggerate facts and mislead consumers' psychology. However, quality is not spoken by the mouth, but is manufactured. Smart consumers can obtain the correct quality evaluation by carefully analyzing the actual products of the manufacturer, actual testing, and relative comparison in today's advanced information technology.
Finally: choose a set of wireless microphone products that can suit your needs and feel satisfied after using it. In addition to understanding the above reference principles, the real action is to collect more relevant information and listen to the actual comparison before you can buy the product. Great value product. However, technological products are changing with each passing day, and the functions are constantly updated. Since you want to buy a new product, you must choose the more advanced models of today. Even if the price is a little bit more expensive, you don’t have to hesitate. The superior advanced products are worth it. You have priority!