What is a microphone? Getting to know the microphone and its different types
In this article, we are going to introduce the microphone and its different types.So what is a microphone and what are its uses?
Maybe you have thought many times about what a microphone is and how it works?
First, we must have a brief definition of the microphone. A microphone or speaker is a device or sensor that converts sound into electricity. In colloquial speech, a microphone is also used as a mic. A microphone is a device that converts sound into electricity and a sensor that converts sound into electrical signals.
The history of the microphone
In 1876, Emile Berliner invented the first microphone that was used as a voice transmitter in telephones. Microphones have many applications in telephones, voice recorders, karaoke systems, hearing aids, film and animation production, sound engineering, private radio telephones (like walkie-talkies but at longer distances), hand speakers, making radio and television programs, recording sound on computers. , speech recognition systems, VoIP, as well as non-audio applications (outside the range of human hearing, which is from 20 to 20,000 kHz) such as ultrasound examination and troubleshooting systems.
Today, most microphones use electromagnetic induction systems (dynamic or dynamic microphones), capacitance change (capacitor or condenser microphones), piezoelectric tension, and light mounting (modulation) to generate electrical signals from mechanical waves. Each microphone has five main and important features:
- Frequency response
- Being oriented
Different types of microphones
What is a dynamic microphone? In dynamic microphones, the sound signal is created by moving a conductor through a magnetic field. In most dynamic microphones, a very thin and light diaphragm moves in response to air pressure. The movement of the diaphragm causes a voice coil to move through a magnetic field, resulting in a small electric current.
Dynamic microphones are less sensitive to air pressure and high frequencies than other types of microphones and can usually work better and perform better in difficult conditions. For example, in live performances and on stage, they are more resistant to the noise of the crowd and surrounding noises. These microphones are cheaper than other types of microphones and are more suitable for recording drums and electric guitars.
If you are looking for a reliable and widely used microphone, then you should start with a dynamic microphone. Due to the fact that their diaphragm is a magnetic coil, these microphones can capture the desired sound well in the most crowded spaces. Finally, it should be noted that these microphones are not only for use in high volume environments, but also work well in low volume environments.
What is a condenser microphone? condenser microphones show a better response to the speed and mobility of sound waves compared to dynamic microphones. This simple mechanical system consists of a thin, elongated diaphragm placed near a metal plate. This arrangement creates a capacitor that receives its electric charge from an external source (battery or dedicated power source, phantom power, or from a mixer).
The diaphragm vibrates slowly in response to the change in air pressure, causing the capacitance of the capacitor to change and creating the output signal of the microphone. Condenser microphones are produced in two types, transistor and lamp, and in different shapes and dimensions, all of which work based on these principles.
Advantages and Disadvantages
Unlike other microphones, a condenser microphone requires a DC power generator and a preamplifier. Condenser microphones have disadvantages, such as size and excessive sensitivity. At the same time, it will be complicated in front of nearby loud sound sources.
Condenser microphones are very sensitive and the slightest sound can cause the diaphragm to move. Condensers are powered by low voltage power, known as phantom power, to provide a strong output. This feature is very desirable because you no longer need to give the signal a lot of gain by the preamp to achieve sufficient power.
If you use the wrong microphone with insufficient output, the resulting signal will probably need a lot of preamp amplification. Most of the low-end preamps do not have the ability to apply the necessary gain, or by increasing the gain, they add a lot of noise to the signal. Condenser microphones eliminate this problem.
This microphone produces a very good quality of sound (typically 20 to 18,000 Hz) and has a very high response to transient sounds. Condenser microphone is used for very sensitive sound recording, such as sound recording in moving and static scenes, especially when the sound source is far away. On the other hand, this microphone can be used as a sound boom, a hand boom, a stand and a pendant.
What is an electret microphone? This type of microphone is a special type of condenser microphone that is widely used as a personal microphone or a hidden microphone and has good sound quality. This relatively cheap and small type of microphone has a plastic diaphragm that has a permanent electrostatic charge, so it does not need a polarizing voltage.
A small battery powered amplifier is built into the microphone housing. As a result of getting old and working a lot, problems arise in the performance of this microphone. Among them, the loss of high frequencies, the reduction of sensitivity and the increase of background noise. Disturbances in this microphone are accelerated due to high humidity, steam, heat and dust.
What is a ribbon microphone? Ribbon microphones were the first directional microphones that were commercially successful and were widely used in the golden age of radio. Nowadays, ribbon microphones are making a comeback in the field of audio, thanks to the efforts of companies like Royer.
Ribbon microphones react to the speed of air molecules instead of the sound pressure level (SPL), and in them a very small suspended element moves in a strong magnetic field. In studio applications this performance difference is not significant, although it can be critical during outdoor recording on windy days.
What is a USB microphone? USB microphones are one of the new developments in microphone technology and have all the components of traditional microphones: capsule, diaphragm, etc. The difference of this microphone is having two additional circuits. An internal preamplifier and an analog to digital (A/D) converter.
The preamplifier makes connecting the microphone to the mixer or external microphone preamplifier unnecessary. The A/D converter converts the microphone output from analog (voltage) to digital (data), so that it can be directly entered into a computer and read by recording software. This microphone makes portable digital recording very easy. Just connect the microphone to the computer, run the software and hit the record button.
Wireless microphones (VHF or UHF)
What is a wireless microphone? In recent years, the development of wireless communication took a big leap with the advent of cell phones. This is while in 2003 wireless communication celebrated its 100th anniversary. One hundred years ago, on June 19, 1903, the first wireless telegraph message was sent across the Atlantic to England by President Roosevelt, and this is the starting point of wireless communication and its birth, so that today wireless communication has somehow penetrated the dimensions of our lives.
Wireless microphones are not excluded from this issue and now more than 200 different types of these microphones are produced and supplied by manufacturers all over the world.
A wireless microphone system usually consists of three main parts: microphone, transmitter and receiver. But what gives this equipment the ability to remove the wire compared to conventional microphone systems, is definitely its transmitter and receiver components. The transmitter part of this equipment is usually integrated and supplied in the form of a set, together with the microphone part and without wires.
In new wireless microphone systems, there are two different antennas, one on the transmitter part and the other on the receiver part. When the distance of the transmitter from the receiver antenna increases beyond the permissible limit, in this case the voice and radio signals are distorted and noisy. In addition, the use of high frequency band (UHF) waves, which have a shorter wavelength than (VHF), reduces the reflection of signals in the used environment.
What is a collar microphone? As the name of this microphone suggests, it is a small microphone that is attached to the collar of your shirt. This type can be both wireless and wired. Collar microphones are usually placed about 6-8 inches below the subject’s chin. These microphones work best when they are not covered by clothing or obstructed by anything.
But if you want to make sure they’re hidden, you can often hide them between a button-down shirt, under a tie or scarf, or even tucked into a shirt or jacket.
Polar pattern of microphones
The polar pattern of the microphone shows us how the microphone hears the sound, that is, from which angle or the surrounding space the microphone absorbs and blocks the sound. Knowing the correct polar pattern of microphones will help you to make the right decision in choosing the right microphone for your desired work.
Cardioid or unidirectional microphones
The cardioid microphone doesn’t just hear, it listens like humans. Technically, the cardioid microphone is most sensitive to sound from the front side. It takes the sound from the sides to some extent and strongly rejects the sound from the back. This is why most stage and studio microphones have a cardioid pattern. Cardioid mics are great for encoding vocals and anything that’s supposed to sound dry and closed.
This front-facing pattern allows you to point the microphone towards the sound source, isolating it from unwanted background noise. This feature makes cardioid microphones ideal for live performances and other occasions where noise reduction and feedback prevention are essential.
Graphic form and uses
The graphic shape of this pattern is almost similar to a heart (that’s why it is also called cardioid). The ability to reject sounds behind the microphone makes cardioid microphones ideal for situations where multiple microphones are used at the same time or when you don’t want the sound of the room’s ambience to be picked up by the microphone.
These microphones, which can be used both for studio and live performance, have a high percentage of microphone users. Remember that cardioid microphones, like other unidirectional microphones, have a proximity effect, that is, if you move the microphone too close to the sound source, the bass will increase.
Cardioid microphones are much more popular than microphones with other patterns. These microphones are used in all kinds of live performances from karaoke to stadium performances. Its other uses are microphone placement of loud instruments such as drums and guitar speakers (cabinets).
Super-Cardioid and hyper-cardioid microphones
These microphones have almost the same orientation as the front axis. These types of microphones have a pattern between cardioid and figure eight (Figure 8). It means that in addition to receiving the sound from the front, they also have some sensitivity to receive the sound from the back and mostly reject the sound or suppress the sound from the left and right direction.
Unlike cardioid mics, both of these polar patterns have a sensitive back (smaller in super-cardioids) that picks up the sound, making placement of these mics a bit tricky.
This category of microphones are microphones that record sounds from all angles, and that is why they are called omnidirectional microphones. They are equally sensitive to sound from all directions. Due to their non-directional design and due to the fact that they do not block the sound in any direction, they capture the nuances and subtleties of the sound better, which makes the sound more natural.
Omnidirectional microphones are often used to record orchestras. But they can also be very useful in the home studio. For example, when you record acoustic guitar, percussion, or background vocals, or whatever seems to sound best in the room. The obvious weakness of this type of microphone is the lack of noise reduction behind the microphones, which causes monitor feedback, so they are not suitable for noisy stages.
Figure eight or bi-directional microphones
The name of this microphone comes from the graphic shape of its polar pattern, which is similar to the English number 8. In short, this type of microphone is sensitive to the sound from the front and back and records it, but isolates the left and right sides, which makes them ideal for stereo recording, or recording two or more instruments. make
This topic may not seem very useful to you at first. But there are many interesting and advanced applications for figure 8 microphones. By the way, figure-8 is the natural pattern of ribbon microphones, and most multi-pattern condensers can be set to figure-8.
Other than that, figure 8 microphones are very rare. Only a few manufacturers (including Newman) offer figure-8 small-diaphragm condenser microphones.
What is a shotgun microphone? Shotgun microphones, which are also called linear and gradient microphones, have a tube-like design that makes their polar pattern even more directional than hypercardioids. The microphone capsule is placed at the end of the tube containing the microphone and eliminates the surrounding sound using phase neutralization.
These microphones are sensitive to sound from all around according to their pattern shape, but they differ in the amount of this sensitivity. In such a way that their focus is on the sound in the front, then the back and finally the sides.
This design makes the microphone have a narrower polar pattern, with a longer range in front. Although shotgun mics are mostly used for film and cinema, they are also great overhead mics for things like vocals, choirs, and cymbals.
Subcardioid or wide cardioid microphones
These microphones have a pattern between cardioid and omni-directional. As you can see in the picture of this model, these microphones record sound from all directions, but they are less sensitive to sound from behind and around than multi-directional microphones.
Microphone diaphragm and its sizes
Diaphragms have a lot to do with sound. Every microphone has a diaphragm and understanding the diaphragm is very important to master the microphone. What is a microphone diaphragm? The microphone diaphragm is a thin membrane that moves in response to changes in sound pressure (sound waves). The diaphragm of the microphone is a main component of the converter in converting sound energy into electrical energy.
Diaphragm is an important part in the preparation and construction of the microphone. In fact, without a movable diaphragm, a microphone cannot perform its function as a transducer. The simultaneous movement of the diaphragm with the sound pressure is the first step in changing sound energy to electrical energy.
Since the microphone diaphragm is very thin, we see that it has only two sides. The movement of the diaphragm is predicted based on the difference in sound pressure between its two sides.
The microphone diaphragm is part of a larger unit inside the microphone called the capsule. The design of the capsule is very important in the performance of the microphone. Finally, the capsule is the transducer element in every microphone.
Microphones pick up sound through their diaphragm; A thin layer of a material that vibrates when struck by sound; This vibration converts sound energy into electrical energy. Although there is no standard unit for measuring the size of diaphragms, there are currently three main categories for the diaphragm size of microphones, all of which refer to the mass of the diaphragm. The size of the diaphragm affects the amount of tension and control of sound pressure, sensitivity, dynamics and internal noise of the microphone.
Small diaphragm microphones are generally known as pen microphones due to their narrow cylindrical shape. Their low-volume design makes them light and easy to use, and it is interesting to know that they are designed in such a way to be strong and able to provide pressure level elasticity (volume) and a high dynamic range. They can be used for guitars, hi-hats, cymbals and other instruments. The known limitations of this type of diaphragm are low sensitivity and high internal noise.
Medium-diaphragm microphones are sometimes called hybrid because they combine the properties of large-diaphragm and small-diaphragm microphones. They have a warmer and fuller sound, close to the sound of large diaphragm microphones, while maintaining the properties of small diaphragm microphones.
These modern microphones are gaining popularity in both studio and live performances, but if you are building a home studio or have a small hall, you can skip them; Especially if you already have a large and small diaphragm microphone.
The larger the diaphragm, the more vibrations it absorbs from the air, and the more vibrations it absorbs, the more accurately the audio details are removed. Unlike small diaphragms, which are rigid, large diaphragms vibrate more easily, which allows them to detect the smallest change in air pressure.
This makes the sound clearer and more natural. This very high quality and resolution has made the presence of large diaphragm microphones in studios a standard. These diaphragms are the most used structure in new generation USB microphones. You can use them to record anything, from a singer’s voice to a guitar or any other instrument.