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two. Before you understand the type of wireless microphone, you should first have a basic concept in the category of the product to choose the model that suits your needs. The categories of wireless microphones can be distinguished into many different types according to different definitions.
1. Differentiated according to the frequency of transmission:
a. FM wireless microphone: Commonly known as FM refers to the FM 88-108MHz international FM broadcasting band. Early consumer wireless microphones are received by FM radio. The system is simple and low-cost. However, due to the use effect, it can meet the requirements of professional quality. At present, it can only be a toy for children or students.
b. VHF wireless microphone: It is divided into two types: low frequency and high frequency. The former uses VHF 50MHz 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 Therefore, this type of Products, which have been replaced by high frequency bands, have gradually disappeared from the market. The latter uses the frequency band of VHF200MHz. Due to the high frequency, the antenna is short, and even can be designed as a hidden antenna. It is convenient, safe and beautiful. The clutter interference of the electrical device is greatly reduced. The circuit design is very mature and the parts are popular. It is cheap, so it has become a popular model on the market today.
2. Differentiated according to the receiving method:
a. Automatic diversity receiving wireless system (True diversity receiving wireless system): due to the "dead-point" physical phenomenon in the radio wave, the receiver's sound output, resulting in intermittent or unstable shortcomings, in order to To solve this kind of defect, the professional model must be improved by the "automatic switching diversity receiving" method of the dual antenna and the dual tuner.
b. Non-diversity receiving wireless system: Due to the complicated and precise circuit design of the above models, the assembly is difficult and the cost is high. Generally, the low-cost models do not adopt the automatic signal selection design. Therefore, it is also impossible to eliminate the disadvantage that the wireless microphone generates a sound interruption during use. This type of machine certainly cannot meet the basic requirements for professional use.
3. Differentiated according to the oscillation mode:
a. Quartz lock (Qualtz locked) model: The quartz oscillator generates a fixed and stable fixed frequency for transmission and reception. The circuit is simple and low cost. It is the standard circuit design of today's wireless microphones. This type of microphone and receiver are only fixed for a single frequency pairing and cannot be changed or adjusted.
b. Phase Locked Frequency Synthesis (PLL Synthesized): In order to avoid the wireless microphone being unable to use the interference caused by other signals during use, or to use multiple microphones at the same time, it is necessary to change the channel conveniently and quickly at any time. The circuit design of the PLL is used to achieve the requirements of this function.
4. According to the number of receiver channels:
a. Single-channel model: Only one channel of non-automatic signal selection or automatic channel selection receiver is installed in the chassis of a receiver. The former has almost no market in Taiwan, but the export market is the cheapest because of the price ( Large color goods). The latter is simple and stable in characteristics, and is the best model for multi-channel simultaneous use in professional situations to avoid signal interference.
b. Dual-channel model: Two channels of non-automatic signal selection or automatic signal selection receiver are installed in the chassis of a receiver to make full use of the space of the chassis and reduce costs. The former is the so-called "Asian fighter type" model. Because of its simple design, it has become the main model for mass production of low-priced manufacturers in Taiwan. In the latter, because of the complexity of the mechanism and the circuit, the internal interference processing and the antenna hybrid matching are not easy, and only a few models are available in the manufacturers of professional models.
c. Multi-channel models: In a receiver's chassis, more than four channels of receivers are installed, most of which adopt the modular design of the modular receiving module. It is mainly suitable for the use of rack-mounted professional models.
three. The choice between price and quality Recently, wireless microphones made in Taiwan have been significantly improved in quality due to the improvement of consumer demand: the price has fallen sharply due to fierce competition from manufacturers. Therefore, some small-scale manufacturers, in order to win orders, are not committed to the development of more advanced models, but are committed to producing cheaper and cheaper models to attract consumers. As the saying goes: "A penny, a share of goods", consumers often buy a poor quality product because of the cheap price. Some consumers are misled by excessive superstitious brand names or by advertisements that are not genuinely advertised by the manufacturer. As a result, the value of the money is not refunded. How to choose a value-for-money model, first of all to meet the quality positioning required by yourself, and to further understand how to evaluate the quality of wireless microphones, in order to choose a truly satisfactory product.
four. The technical background of the manufacturer determines the quality of the product. The wireless microphone product is a product designed by combining audio and wireless communication technology. It is completely different from the technology and equipment for manufacturing wired microphone. Therefore, the wired microphone manufacturer that also manufactures the "microphone" is not necessarily Manufacturers who can manufacture wireless microphones and manufacture wireless communication products may not be able to manufacture good wireless microphones. Only manufacturers with long-term professional audio technology and wireless high-frequency technology can make excellent wireless microphones. A few years ago, the famous SHURE company that manufactures wired microphones often advertises that its wireless microphone can be as good as its wired microphone SM-58, which is a misleading consumer advertisement! Because wireless microphone products are the biggest difference from other wired products, the effect is very closely affected by environmental conditions. Therefore, a good quality wireless microphone can not be designed in the laboratory in a short period of time. It also needs to be used for a long time. After the actual use of various environments, the gains and losses will be returned to the design engineer, and after continuous research and development, a truly perfect product can be produced. Therefore, if you choose a good wireless microphone product, you must choose a professional technical background and long-term manufacturing experience.
Fives. An excellent wireless microphone should have the following excellent features:
1. The exterior design has an ergonomic and aesthetically based design: the body of the hand-held wireless microphone must have a size suitable for the hand and a beautiful shape. The traditional tube body is a bamboo tube or a trapezoid, which is not aesthetically pleasing. It is too suitable for hand grasping, especially for users who are prone to sweating, it is not easy to grip and slip. The most suitable shape for the hand grip is a double inner curve shape with a smaller intermediate diameter than the two ends. Just like the Chinese Guanyin bottle or the woman's waist, it is not only beautiful but also easy to grip.
2. Hand-held microphones use advanced hidden antenna design: the biggest difference between a person and a monkey is that there is no tail. Early wireless microphones have an external antenna at the end, and the advanced wireless microphone overcomes the technical difficulties, no longer uses the outdated external design, and uses the perfect hidden antenna design to make the wireless microphone easy to use. Safe, beautiful and without breaking the advantages of failure.
3. To assemble a good sound head: the quality of the sound head determines the first level of the quality of the wireless microphone. The sound head has two types of moving coil type and capacitive type. The moving coil type is a coil supported on the diaphragm, and converts sound energy into an electric energy signal between high-density magnetic fields. This voice head has a certain limit on the voice coil characteristics. But basically the structure is simple and the price is cheap, which is the most popular model on the market. The condenser microphone is a combination of electronic and structural high-level microphones. The pronunciation is based on the change of the capacitance between the poles. The ultra-thin gold-plated diaphragm directly converts the sound into electrical energy signals. The most important feature of the advanced condenser microphone is that it can display extremely clear 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 small, the volume is light and fall, and the touch noise is low. Used in professional equipment such as recording studios, professional stages, and test instruments. The only drawback is the need to provide a bias (Phantom Power), but because the wireless microphone itself has a power supply, the condenser head is the best match for the wireless microphone, so that all the advantages are on the wireless microphone. At present, Taiwan MIPRO wireless microphone is the only product equipped with advanced condenser sound head.
4. The microphone has the advantage of low-touch noise: the hand-held wireless microphone has a frictional touch noise generated between the palm and the palm of the hand, which has an impact on the normal sound quality, especially the wireless microphone itself has a sensitive preamplifier, making the touch noise The performance is more serious and becomes a technical bottleneck. The general wireless microphone has no professional design experience, and in order to reduce the manufacturing cost, the use of simple circuit, the use of cheap sound head, suspension design and low-cost body surface treatment, so the sound quality is not clear can not overcome the significant microphone The noise is degraded by touching the noise, so if you choose a wireless microphone with good quality, you must pay special attention to the characteristics of extremely clear sound quality and ultra-low touch noise.
5. It has the function of eliminating the interruption or instability of the sound: the signal transmitted by the wireless microphone is attracted and reflected by the surrounding environment, causing the signal received by the receiving antenna to have a dead angle, which causes the output sound to be interrupted or unstable, especially in the This phenomenon is not allowed to occur in professional use. In order to solve this shortcoming, only the most advanced automatic signal receiving system can be used to achieve the best results. The popular dual-channel receivers that are popular in the market do not have such an automatic selective reception function, and cannot avoid the above disadvantages, so they can only be used in short-range family karaoke occasions. In a professional place or a user who values ​​sound quality, the model of the automatic signal receiving system must be selected to meet the sound quality requirements and obtain a perfect performance.
6. It has the function of preventing the noise from being disturbed during standby. Most of the receivers have the mute control function (Squelch Control). When the power is turned on without the microphone signal input or the intensity of the number is lower than a certain signal-to-noise ratio, the mute control circuit The output circuit is turned off 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 sound of the microphone. However, when the microphone power is turned on and off, or when the microphone signal is turned off, occasionally encountering signal interference beyond the mute control strength, the receiver mute circuit will be activated by these impact noise and interference noise to output a loud noise. In order to solve this deficiency, the so-called "audio lock mute circuit" is installed in the advanced model to suppress it. The principle is to add a fixed super-audio modulation signal to the microphone's transmission signal: a discriminator is also installed inside the receiver, so that the receiver must receive the microphone signal containing the fixed super-tone modulation signal. The output circuit can be activated to prevent interference from other signals or noise. In order to protect your valuable audio system from being damaged by loud noise, you must select a model with tone lock mute function.
7. Multi-channel use does not interfere with each other: The biggest technical bottleneck in the use of wireless microphones is the problem of signal interference, especially the more frequently used, the more serious the interference problem, so when multiple wireless microphones are used at the same place, To avoid interference, in addition to carefully selecting frequencies that do not interfere physically with each other and avoiding adjacent external signal interference, the receiver should have excellent selectivity, and the radiated harmonics of the transmitted and received signals should be filtered out to be very clean. Avoid signal interference. Generally, the receivers in the VHF band can be used for 12 frequencies at the same time. The MIPRO products in Taiwan can achieve 24 frequencies and do not interfere with each other at the same time. Even under certain conditions, they are specially designed. And arrangements can be used to achieve more frequencies at the same time.
8. To solve the problem of multi-channel simultaneous use and avoid interference, multi-channel series models with digital lock can change the frequency: the traditional wireless microphone system adopts quartz lock fixed frequency design, and this type of machine can be used in occasions requiring multi-channel use. In the case of strong signal interference, it is impossible to replace the frequency that you wish to use, but it must be replaced. In order to solve this deficiency, advanced models use phase locked frequency synthesis (PLL Synthesized), and pre-stored dozens of frequencies in the transmitter and receiver can be arbitrarily changed by the user, although this advanced design is more expensive. However, it provides a very convenient function for distribution and users to completely solve the above-mentioned shortcomings. Taiwan has MIPRO's energy production, the most advanced and most reasonable price series.
9. To avoid frequency "carrying" or signal interference, digital locking UHF channel system products should be used: Due to the current use of wireless microphones in the VHF200MHz frequency band, the interference of signals and the interference of various electrical noises are becoming more and more serious. The frequency of professional-grade wireless microphones is gradually increased to the UHF band of 800MHz, and the PLL phase locking circuit is adopted. The preset multi-channel can be switched at will, avoiding the interference of other signals and general electrical noise, and obtaining the best use effect. Due to the complicated circuit design of the UHF band and the high-frequency components used, the current price is still high, and there are fewer manufacturers in mass production. However, the UHF model is the best choice for professional quality and gradually becomes the future. The trend is popular. Taiwan still uses MIPRO to produce a full range of advanced models and complete peripheral equipment.
10. Products with international quality certification and qualified by telecommunications regulations: Excellent wireless microphone products must be manufactured by an international quality certification factory, and must be certified by national radio wave regulations before they can be legally sold and used. Consumers should choose to use certified products for quality assurance.
six. Collection and evaluation of data:
The most basic source of information for purchasing products is the catalogue and magazine advertisements provided by the manufacturer. However, manufacturers with small scale equipment are not able to provide correct values, so that consumers cannot understand the analysis and comparison from the catalogue. Some manufacturers use catalogues and advertisements to make exaggerated facts and mislead consumers' psychology. But the quality is not made with the mouth, but it is made. The smart consumers are in the developed information today. As long as the actual products of the manufacturers are used for detailed analysis, actual testing and relative comparison, the correct quality evaluation can be obtained.
Seven. in conclusion:
Choose a set of wireless microphone products that can suit your needs and be satisfied after use. In addition to understanding the above reference principles, the real action is to collect more relevant information and actually listen to the comparison before you can buy the material super. The value of the product. However, the products of science and technology are changing with each passing day, and the functions are constantly updated. If you want to buy a new product, you must purchase the most advanced models. Even if the price is more expensive, you don’t have to hesitate. You have priority!
How to choose wireless microphone http://
(Source: Audio Application)
Getting Started with Headphones Basics For many entry-level users, when you buy headphones, you will often get lost by the clouds and fog of a lot of parameters. In fact, these parameters are not complicated. I hope you can read this article. The purchase can help.
First, how the earphones are classified. 2. According to the degree of openness, the relevant parameters of the earphones and the sound quality terms respectively represent what the meaning is. 4. Regarding the earphone wire, how the earphones are classified according to the principle of transducing (transducer) is mainly the moving circle. There are two types of (Dynamic) and electrostatic (Electrostatic) earphones. Although there are several kinds of magnetic types in addition to these two types, they are either eliminated or used in professional markets. Do the discussion.
Dynamic ring headset principle: At present, most (about 99%) earphone earphones belong to this class. The principle is similar to ordinary speakers. The coil in the permanent magnetic field is connected with the diaphragm, and the coil drives the diaphragm to sound under the signal current drive. .
Electrostatic earphone: The diaphragm is in a changing electric field. The diaphragm is extremely thin and accurate to a few micrometers. The coil drives the diaphragm to sound under the driving of the electric field force.
Second, according to the degree of openness, mainly open, semi-open, closed (closed)
The open-type headphones generally have a natural sense of hearing and are comfortable to wear. The hifi/target=_blank>HIFI earphones, which are commonly used in homes, can be leaked, and vice versa. The external voice can also be heard. The earphones have less pressure on the ears.
Semi-open: There is no strict regulation. The sound can only be entered or not, and the corresponding adjustment can be made according to the need: the earmuffs are pressed against the ear to prevent the sound from entering and exiting, and the sound is correctly positioned. This type of video is more common in the field of professional monitoring, but one of the disadvantages of this type of headphones is that the bass sound is severely dyed.
Superlux HD681
Third, the earphones some related parameters and sound quality terms respectively mean what. 1. Headphone related parameter impedance (Impedance): pay attention to the difference between the meaning of the resistance, in the world of direct current (DC), the effect of the object on the current obstruction is called resistance, but in In the field of alternating current (AC), in addition to the resistance that blocks the current, the capacitance and inductance also hinder the flow of current. This effect is called reactance, and our daily impedance is the sum of the resistance and the reactance in the vector. . Generally speaking, low-impedance headphones are better to push, but you must first turn down the volume and then plug in the headphones, then adjust the volume a little bit, so as to prevent the headphones from being overloaded or the voice coils being deformed. Causes broken sound, so portable and power-saving machines such as Walkman should choose low-impedance headphones, but also pay attention to high sensitivity, sensitivity index is more important for the Walkman.
Sensitivity: The sound pressure level that the earphone can emit when the input power of 1 mW is input to the earphone (the unit of sound pressure is decibel, the louder the sound pressure is, the higher the volume), so the higher the sensitivity, the smaller the impedance, the earphone The easier it is to sound, the easier it is to drive.
Frequency Response (Frequency Response): The sensitivity value corresponding to the frequency is the frequency response. The image is the frequency response curve. The range of human hearing can reach 20Hz-20000Hz. The mature earphone technology has reached this level. Claim.
2. Sound quality evaluation Term range: The range between the highest and lowest sounds that can be achieved by a musical instrument or human voice.
Tone: Also known as a sound, one of the basic attributes of sound, such as erhu and pipa, is a different tone.
Sound Dye: The opposite of the natural neutrality of music, that is, the sound is dyed with some features that the program itself does not have. For example, the sound that is heard in a jar is a typical sound. The sound dye indicates that some of the components are added (or reduced) in the reproduced signal, which is obviously a distortion.
Distortion: The output of the device cannot fully reproduce its input, resulting in distortion of the waveform or an increase or decrease in signal components.
Dynamic: Allows you to record the ratio of the largest message to the smallest message.
Transient response: The ability of the equipment to follow burst signals in music. The equipment with good transient response should respond immediately when the signal comes, and the signal will stop when it stops, and it will never drag the water. (Typical instrument: piano)
Signal-to-noise ratio: Also known as the signal-to-noise ratio, the useful components of the signal are compared to the strength of the noise, often expressed in decibels. The higher the signal-to-noise ratio of the device, the less noise it produces.
Air Sense: An acoustic term used to indicate the treble or the spatial separation between instruments in the sound field. At this time, the high frequency response can be extended to 15 kHz to 20 kHz. The antonyms are "dull" and "thick". ?
Low frequency extension: refers to the lowest frequency that audio equipment can reproduce. It is used to determine the extent to which the sound system or speaker can dive when replaying the bass. For example, a small subwoofer can have a low frequency extension of 40 Hz, while a large subwoofer dive to 16 Hz.
Bright: refers to highlighting the high frequency range of 4kHz-8kHz, where the harmonics are relatively stronger than the fundamental. There is nothing wrong with the brightness itself. The live concerts have bright sounds. The problem is that the brightness is well controlled, and the brightness is too bright (or even whistling).
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4. About the earphone wire Most earphone cables are made of copper. The general purity (usually expressed by a few N, such as 4N, 6N...) is the better the conductivity, the smaller the signal distortion, the common ones are:
TPC (electrolytic copper): purity is 99.5%
OFC (Oxygen Free Copper): 99.995% purity
LC-OFC (linear crystal oxygen-free copper or crystalline oxygen-free copper): purity above 99.995% OCC (single crystal oxygen-free copper): the highest purity, above 99.996%, divided into PC-OCC and UP-OCC
How to choose a wireless microphone
one. Overview Due to the advancement of today's radio communication technology, the quality and function of wireless microphone products have been relatively improved, reaching mature and practical fields: the number of manufacturers is increasing, and the price is also declining due to competition, triggering the gradual decline of consumers. Hobbies and universal application. The author has been engaged in the sales of professional wireless microphones for eight years, providing the latest technical requirements for the design of this product, so that consumers can judge how to purchase a value before purchasing this product. Excellent products, but also provide manufacturers reference, explore how to produce and sell advanced products that consumers are satisfied with.