Operating principle
- Dynamic. “Conventional,” or coil,
dynamic microphones use a system of a diaphragm (membrane) and a coil that is placed in a magnetic field. From sound vibrations, the membrane, and with it the coil, begin to move, and an electrical signal is generated in the coil. Such models are relatively inexpensive, durable and reliable, and also cope well even with very loud and harsh sounds; in addition, they are more compact and lighter than the other type of dynamic microphones - ribbons (see below). Their main disadvantage is poor efficiency at high frequencies.
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Dynamic (tape). A variation of the dynamic microphones described above, in which the membrane is connected not to a coil, but to a thin (several microns) metal tape, hence the name. Historically, this is the first type of microphone with a dynamic operating principle, however, due to a number of shortcomings, it gradually lost wide popularity, giving way to coil-based options. Such disadvantages are, first of all, large size and large mass, complexity and high cost of production, as well as very low output impedance, which complicates the work with amplifiers. At the same time, tape models are characterized by extremely high accuracy of sound transmission over the entire frequency range, which allows them to be used in recording studios, at high-profile concerts, etc. Most modern models of this type are professional models, in particular
...studio ones (see “Purpose”).
— Condenser. The name of this type is due to the fact that the microphone is actually a capacitor, in which the role of one of the plates is played by a sensitive membrane (usually made of a metallized polymer). Due to the vibration of the membrane (under the influence of sound vibrations), the distance between the plates and, accordingly, the capacitance of the capacitor changes - these fluctuations in capacitance provide an electrical signal. Condenser microphones have uniform sound transmission over the entire frequency range, with a minimum of distortion, due to which this technology has found wide application in professional audio equipment. It is worth considering that for such a device to operate, additional power is required - the so-called. “phantom” (standard voltage - 48 V). However, this cannot be called a clear disadvantage, because amplifiers, receivers and other high-end equipment are often made with this requirement in mind. But obvious disadvantages include high price, sensitivity to shock and strict requirements for temperature and humidity; the latter makes condenser microphones poorly suited for outdoor use.
— Capacitor (tube). A specific type of condenser microphones described above. They use the same principle of sound production (with all the advantages and disadvantages), however, the amplification element in such models, in accordance with the name, is built on vacuum tubes. Technically, such an amplifier introduces more distortion into the signal than a transistor one, but this distortion gives the sound a characteristic coloring that is pleasant to many listeners. Simply put, you get that notorious “warm tube sound”; Moreover, achieving such an effect using a microphone is cheaper than using a tube amplifier, and for a number of technical reasons this option often turns out to be optimal. Almost all tube microphones have a studio purpose (see above). Their main drawback is their high price (several times more than that of “regular” capacitor analogues). In addition, such models have their own nutritional characteristics; To supply energy, a special adapter is usually supplied, which is also responsible for controlling additional functions such as changing the radiation pattern.
- Electret. In design, such microphones are similar to the condenser ones described above, but their design includes a plate made of the so-called. electret - substances with special electrical properties. This provides a number of advantages: electret microphones can be used outdoors without much difficulty, they can be made more compact, and such models are cheaper to produce; At the same time, the quality of sound transmission can be quite comparable to condenser ones. As a result, this technology is found in a wide variety of models - from miniature lavaliers and simple computer ones to studio ones (see “Purpose”). Note also that electret microphones also require external power, but this is not always phantom 48 V - for some varieties, a small amount of energy is sufficient, which can be provided by a compact battery or power supply via a 3.5 mm mini-Jack cable.Frequency range
The range of audio frequencies normally perceived and processed by a microphone.
The wider this range — the fuller the signal, the less likely that too high or low frequencies will be missed due to the imperfection of the microphone. However, in this case, it is worth considering some nuances. First of all: a wide frequency range in itself does not guarantee high sound quality — a lot also depends on the type of microphone (see above) and its frequency response, not to mention the quality of other components of the audio system. In addition, a large width is also not always really necessary. For example, for normal transmission of human speech, a range of 500 Hz — 2 kHz is considered sufficient, which is much narrower than the general range perceived by the human ear. This general range, in turn, averages from 16 Hz to 22 kHz, and also narrows with age. Do not forget about the features of the equipment to which the microphone is connected: it is hardly worth specifically looking for a model with an extensive range, if, for example, the amplifier to which it is planned to be connected severely “cuts off” the frequencies from above and/or below.
Sensitivity
Sensitivity describes the signal strength at the output of a microphone when it processes a sound of a certain volume. In this case, sensitivity means the ratio of the output voltage to the sound pressure on the membrane, expressed in decibels. The higher this number, the higher the sensitivity. Note that, as a rule, values in decibels are negative, so we can say this: the closer the number is to zero, the more sensitive the microphone. For example, a -38 dB model outperforms a -54 dB model in this parameter.
It should be borne in mind that high sensitivity in itself does not mean high sound quality - it only allows the device to “hear” a weaker sound. Conversely, low sensitivity is not an unequivocal sign of a bad microphone. The choice for this parameter depends on the specifics of the application: a sensitive device is useful for working with low sounds and in cases where it is necessary to capture the smallest nuances of what is happening, and a “weak” microphone will be convenient at high sound volume or, if necessary, filter out extraneous weak noises. There are models with
sensitivity adjustment(and for models with a headphone output
, headphone volume control may be provided).
Sound pressure
The maximum sound pressure perceived by the microphone, at which the harmonic oscillation coefficient does not exceed 0.5% — in other words, the highest sound volume at which no noticeable interference occurs.
The higher this indicator, the better the microphone is suitable for working with loud sound. Here it is worth considering that the decibel is a non-linear quantity; in other words, an increase in volume from 10 dB to 20 dB or from 20 to 40 dB does not mean a 2-fold increase in volume. Therefore, when assessing, it is most convenient to refer to comparative tables of noise levels. Here are some examples: a level of 100 dB roughly corresponds to a motorcycle engine or subway car noise; 110 dB — helicopter; 120 dB — the work of a demolition hammer; 130 dB, comparable to the sound of a jet aircraft taking off, is considered a pain threshold for a person. At the same time, many high-end microphones are able to work normally at a sound pressure of 140 – 150 dB — and this is a noise level that can cause physical damage to a person.
Power source
The type of power used by the microphone during operation.
- Phantom. 48 V power supply required for operation
of condenser microphones, as well as some types
of electret microphones(see “Type”). With the standard connection, electricity is supplied through the same cable that connects the microphone to the receiving device; Accordingly, for normal operation of such models, amplifiers, receivers or other equipment with a microphone input that has phantom power are required. However, the absence of such an input is also not an insurmountable obstacle - some microphones have adapters that allow you to receive
phantom power from a 230 V network (for more details, see “Included”). Another alternative is the phantom/battery combo described below. In general, this method of power supply is convenient in that it allows you not to worry about the battery charge, but freedom of movement is limited by the length of the power cord.
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Battery. Powered by rechargeable battery. Note that it is often poorly suited for analog capacitor models - the required 48 V is difficult to provide with a small portable battery. But in electret microphones, battery power is used quite often. Another area of application for batteries is models with wireless connections (see “Features/capabilities”), in which autonomous power is required
...at a minimum for the operation of the transmitter. In any case, the battery is convenient due to the absence of unnecessary wires. It, of course, needs to be recharged periodically, but the power consumption of microphones is usually low and the battery life even in the most modest models reaches several hours.
— Phantom/battery. Microphones of this type can operate either from phantom power or from their own built-in battery (for more details on both, see above). This makes them extremely versatile and can be used regardless of the presence of phantom power inputs or suitable adapters. However, it must be taken into account that the performance characteristics when using different power sources may vary slightly; this point is usually indicated in official data.
— Batteries. Powered by replaceable elements of a standard size - most often AA (“pen-AA batteries”). The main advantage of such microphones is the quick replacement of batteries when discharged. Batteries are usually not included in the package and must be purchased separately. However, this provides an advantage - the ability to independently choose the type and brand of replacement batteries.
Note that when connected via USB, the microphone receives the power required for operation through the same connector; For such models, the type of power supply is not separately indicated.In box
- Receiver. Receiver used on wireless models (see Features/Capabilities). The receiver, in essence, plays the role of a radio adapter: it connects to an amplifier or other audio equipment in the classic wired way and transmits the signal from the microphone to this equipment. For more information about the included receiver, see “Radio System”,
— Transmitter. A transmitter used in systems with a wireless connection (see “Functions/capabilities”), or more precisely, a transmitter designed as a separate device. Miniature microphones (primarily lavalier and headset) have this design, in which the housing dimensions do not allow the transmitter to be built directly into the device: the microphone is connected to an external transmitter using a wire, the latter is usually hung on the belt. The presence of a separate transmitter is usually a sign of a compact microphone; and one of the practical advantages of this design is that the microphone can be detached and connected to other equipment (not necessarily a transmitter).
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Monitor mount. A device for attaching a microphone to a computer monitor. For obvious reasons, it is used only in models for computers (see “Purpose”). This feature is especially useful in cases where there is very little free space on the table where the computer is located, or the microphone cannot be placed on the table in the optimal place. The mount can also be useful for working with a laptop,
...although specialized microphones are usually more convenient.
— Holder for stand. A mount in the form of a characteristic round cradle designed to place a microphone on a stand, tripod or other device. Used primarily with vocal and instrumental models (see “Purpose”), it allows you to quickly remove and install the microphone on a stand - which is useful, in particular, during concerts and other public performances. Holders are also sold separately, but buying a model with a complete mount is often more convenient - such a mount is optimally compatible with the microphone and does not require wasting time searching and selecting.
— Anti-shock suspension (“ spider ”). Special shock-absorbing suspension used with studio microphones (see “Purpose”); The slang name "spider" comes from its characteristic shape. The need to use such a suspension is due to the fact that on a regular stand, a microphone can experience various shocks and vibrations (from the operation of equipment nearby, from objects falling on the floor, and even from people’s steps), which create interference in the sound. “Spider” compensates for such shocks and reduces interference to almost zero; At the same time, a complete suspension is more convenient than one purchased separately due to the fact that it is, by definition, compatible with a microphone.
— Pop filter. Such a filter is a plate, usually round, installed in front of the microphone when working with voice - most often during recording; Accordingly, this function is used primarily with studio microphones (see “Purpose”). The protective screen allows sound to pass through well, but it blocks the flow of air that occurs during breathing - thus preventing the appearance of characteristic interference from “exhaling into the microphone.” Another purpose of pop filters is to protect against small splashes of saliva, which can cause corrosion and negatively affect the longevity of the microphone.
— Wind protection. The windscreen most often takes the form of a distinctive “tip,” usually foam, that fits over the microphone; at the same time, in miniature models (for example, head ones, see “Purpose”) the design may be different. However, in any case, the purpose of such devices corresponds to the name: to protect the microphone from exposure to intense air currents that can cause interference. Note that the matter is not limited to wind - a person’s breathing can also become a source of interference if the microphone is located close to the mouth.
— Detachable cable. The ability to detach the cable from the microphone not only makes storage and transportation easier, but also allows you to replace the supplied cable with another if circumstances require it (for example, to connect through a different interface, see above).
- Tripod. A tripod is essentially a portable tripod designed to mount a microphone on a table or other similar surface. This eliminates the need to hold the device in your hand or organize a stand “from scrap materials.” Such tripods are also sold separately, but it is usually more convenient to buy a set; For more details, see "Rack Holder".
- Power adapter. A device that allows you to supply a microphone of a condenser or electret type (see above) with the phantom power required for operation from a regular household 230 V outlet. Thanks to this, it becomes possible to connect the microphone even to tech amplifiers (receivers, players, etc.) that do not have phantom power inputs.
— Case/case. A case is usually called a container made of hard materials, while a cover is usually made of soft materials. The only key difference between them is the degree of protection - the cases are more shock-resistant. But the basic purpose is the same: storing and transporting a microphone in a case/cover is much more convenient than without such a device (in particular, because additional included accessories can usually also be placed inside).
— Charging case. A case is a case made of hard material that simultaneously plays the role of a charger. This feature is very popular in wireless models. The charging case usually has its own battery and the microphone (transmitter) and receiver are charged from this battery; This design provides additional convenience in several ways. Firstly, the case, in fact, also serves as a power bank - an autonomous power source; The capacity of such a “power bank” may vary, but it is usually enough for several full charges. Secondly, the ability to charge small microphones directly in the case reduces the risk of losing them. Thirdly, the charging procedure itself is quite convenient - you just need to connect the cable to the case.
Note that, in addition to the above, manufacturers may include other accessories in the kit - for example, separate clips for attaching lavalier microphones, battery chargers, cleaning wipes, etc.