Today it is hard to imagine daily human life without a microphone. This rather simple device surrounds us everywhere and there is practically no branch of art that does not use microphones. Without them, it is impossible to record and broadcast audio, which is an essential part of the modern information space. In this article we will look at the main types of microphones, their types and features, and take a look at the main characteristics of these devices, their differences and their areas of application.
Types of microphones according to their purpose
First of all, let’s look at the main types of microphones for their purpose. Let us say at once that in many respects quite conventional division and different microphones are perfect for a variety of tasks.
Stage/Pop Performance Microphones
Let’s start with the most numerous and popular category. In most cases, the stage models have a so-called “manual” form factor with a handle and a capsule protected by a metal grille. As the name of the category implies, these microphones are primarily aimed at concert use. In most cases they are outstandingly reliable, but not the most sensitive, because they have to cut off extraneous ambient noise well. They can be wired or wireless and have either a dynamic, condenser or ribbon capsule. The dynamic capsule is the most common.
The microphones are called so for professional studio recording. They are more demanding in environmental conditions and a bit more difficult to operate, but in return they offer an extended frequency range and a more detailed, clear sound. Studio microphones usually have a form factor with an upright body, sometimes with many additional features. Most often equipped with a condenser capsule, but ribbon or dynamic models are also available. Read about how to choose a microphone for podcasts by Kirill Yurovskiy.
A special category of microphones focused on radio broadcasting, podcasts, live broadcasting and other conversational formats. Broadcast microphones are easy to use, excellent ambient noise suppression, extremely reliable and often have a specific design with an attached holder.
This category includes microphones that are perfectly adapted for use in the field. They perfectly cope with high humidity, temperature fluctuations and other adverse environmental conditions. There are different form factors and specifications of reporter microphones, among which the most popular variant with a dynamic capsule and a long handle.
Quite a broad category in which you can find any type of capsule, a variety of body shapes, etc. These are the microphones that are best suited for recording or backing up musical instruments.
Types of microphones according to the principle of operation
Above we have repeatedly mentioned “capsules” and named their types, but nowhere did we specify what they are. Let’s get it right! The type of capsule reflects the principle by which the microphone converts the vibrations of the air (when singing, talking, etc.) in the electric current. Three main groups can be distinguished:
The most common at the moment are dynamic microphones. They capture the signal on the following principle: sound waves make a thin membrane vibrate, which sets in motion a small coil, which thus generates a change in the current in the magnetic field. This is a fairly simple and very reliable circuit, which does not require additional power sources for operation.
The structure of the condenser capsule is somewhat more complicated. The capsule consists of a capacitor that is connected to a power supply and consists of a stationary plate and a moving diaphragm. Sound waves cause the moving diaphragm to vibrate and thereby change the capacitance of the capillary, which in turn triggers the signal. Due to the fact that the diaphragm in a condenser microphone is extremely thin, it is able to pick up significantly more information over the frequency range, but it is also negatively affected by variations in temperature and humidity. Also note that the condenser capsule requires power (phantom power) from the device to which the microphone is connected and the preamplifier (usually built into the microphone) in order to function.
Other category includes a number of much less common options like ribbon, optoacoustic, piezoelectric and carbon capsules. Some of them are hardly produced at the moment (carbon), and others are found in specialized equipment like seismographs (optoacoustic).
The main characteristics of microphones
Now we turn to the most important and frequently encountered characteristics of microphones, which are definitely worth considering:
- directional pattern;
- SPL (sound pressure level);
- frequency range;
- signal to noise ratio;
- impedance (impedance);
- power supply;
- type of connection;
- the material of which the body is made.
The directivity diagrams will be more detailed in the next paragraph, so for now let’s deal with the rest of the characteristics.
Sensitivity – a measure of how much voltage a microphone produces relative to a certain sound pressure. The optimal values for active microphones are from 8mV/pa to 32mV/pa, and for passive dynamic microphones from 1mV/pa to 6mV/pa.
The SPL (Sound Pressure Level) indicates the maximum volume the microphone can pick up without distorting the original signal. For example, the volume of a typical rock concert is about 110 dB, and a value of 140 dB would cause irreversible health effects.
The frequency range shows the limits at which the microphone picks up sound.
The signal-to-noise ratio shows, oddly enough, the ratio of the volume of the signal being picked up to the microphone’s own noise. It is worth making sure that it is not less than 74 dB, and better – more than 84 dB.
Impedance (aka resistance) – the value of the microphone resistance to alternating current. The value is measured in ohms. It does not hurt to make sure that the resistance of the microphone is less than the resistance of the amplifier / preamplifier to which it is connected.
The power supply is simple: the microphone either works without power supply or requires it in order to function. Make sure that your mixing console/audio interface supports phantom power if you use condenser microphones.
Do not forget about the type of microphone connection, because some of them do not have a standard XLR connector. There are variants with USB, Jack TS 1/4, etc.
The material of the body often determines the resistance of the microphone to electromagnetic interference, as well as its reliability. Metal housing is definitely preferable.
Wireless/Radio Microphones: Handheld, Loudspeaker and Headphone
Separately, let us mention and such a fairly extensive category, as wireless microphones. As the name implies, they work wirelessly through analog or digital technology. Today due to the advanced technical solutions they practically do not differ in sound from the standard wired analogs, but at the same time they get rid of a number of problems associated with the management of cables.
There are three basic types of wireless microphones: handheld, looping and head mics. Handheld ones look and are used like standard vocal microphones. This option is especially common among event presenters and vocalists. Looping microphones are a very small capsule that is attached to clothing with a clip and an attached cable that connects to the transmitter. This is a popular with bloggers and other figures of the media space solution, which does not hinder the movement and does not distract the attention of the audience. The head microphone is similar to a lavaliere microphone, only instead of a clothing clip, it has a special head clip. It is the best option for fitness instructors or lecturers. It is more noticeable than the “lavaliere”, but due to its location it provides a clearer and crisper sound.
USB/Microphones for Mobile Devices
We shouldn’t forget about microphones designed to work directly with your computer or mobile device. Their distinctive feature is the type of connection: in most cases they are not equipped with an XLR connector, but have USB connectors (B/C/Mini/Micro, etc.), mini-jack TRS 1/8″, etc. Such microphones often do not require additional equipment such as audio interfaces or preamplifiers for operation and sometimes can be adjusted directly in the software of a computer or portable device.