How Microphones Work

Microphones are very compact nowadays, and they come in different shapes, sizes, and types. But learning how the microphones actually work and understanding different types might be very useful and they could make your recordings better and easier. In this post, we will explain the history, types, and the way microphones work in a very simple way. Even if you don’t have any background in tech and recording, you will be able to pick it up very easily.

At first, microphone might seem like a magic tool that turns sound energy into a electrical energy so we can record and listen to. However, as you start learning the way microphones work, you will find how all the pieces that come together make sense. So get your cup of coffee, stay tuned, and at the end of this post – you will feel like you’ve mastered everything related to the microphones.

Who Invented Microphone?

The word microphone first came from Sir Charles Wheatstone when he phrased it back in 1827. However, the first microphone was invented later in 1876 and it was used as a telephone voice transmitter. The person who invented it was named Emile Berliner after he got the inspiration from one of the first telephones demonstrated by Bell Company.

Later, the Bell Company was impressed with the microphone that Berliner invented and later bought the patent for approximately $50,000 USD. From that moment, different types of microphones were started to getting invented, such as carbon microphone in 1878, ribbon microphone in 1942, and many others types that followed.

Parts of the Microphone

There are two different main types of microphones which are condenser and dynamic. Therefore, the parts of each type of microphone can vary, however, the principle is the same.

The diaphragm is one part of the microphone that every microphone has. It’s a little piece of metal, or sometimes plastic that vibrates when it is struck by sound waves. It’s located in the head of the microphone and is a very crucial part.

The coil is a part that is located in the dynamic microphones. The diaphragm is attached to the coil which also vibrates as diaphragm catches the sound waves. The coil is made to move against a magnet which generates the current.

Capacitor plates are used in condenser microphones. They are basically two metal plates which have a voltage between them. One plate is thinner than the other and it’s picking up the sound. When the plate is struck by the sound, distance between these two plates changes and charge happens.

The parts that are found inside the microphone will determine the type, polar pattern, and will narrow the intended use.

How Does a Microphone Turn Sound Energy into Electrical Energy?

Microphones are actually reversed speaker. The parts that microphone consists, they help them to catch the energy and vibrations in the air that we call sound. When the sounds get inside the microphone, they struck the diaphragm which moves back and forth. Coil follows the same action of the diaphragm.

Then, a permanent magnet produces a magnetic field which cuts through the coil. As coil moves, electric current starts flowing through. That electric current flows out to the amplifier or any sound recording device and that’s how the conversion of sound energy to electrical energy happens.

Microphone Types

Other than two earlier mentioned microphone types, there is also the third most common microphone type. Although it’s one of the oldest types, it’s still commonly used and that’s why we still include it. Each microphone type has its own advantages and disadvantages, and therefore, it’s suitable for a different purpose. Knowing the differences between these three microphone types will help you even from the beginning since it will help you to choose your first microphone.

Condenser Microphones

Condenser microphones consist of diaphragm and capacitor plates. They’re considered to be more sensitive than other microphone types, and they definitely aren’t as robust as other types. However, they have its advantages. They’re often used in recording studios because of their high fidelity as a result of high sensitivity. They’re most suitable for recording vocals, no matter if you’re a singer or just a speaker. Condenser microphones come in many different sizes which is also a great thing. They also offer a high frequency and their response is amazing.

In most cases, whenever you see anyone who’s using a condenser microphone, they’ll also use a pop filter because of its sensitivity. It’s not a bad thing if you’re interested in a microphone that you can easily use in studio and surroundings without a lot of noise.

Dynamic Microphones

Dynamic microphones consist of the diaphragm and a coil which helps generate and transform the sound waves into electric current. Such simple mechanism makes dynamic microphones very cheap and affordable. On the other hand, they provide a lot more durability and reliability design and build wise. They’re not as sensitive as condenser microphones so they’re more suitable for recording louder sounds, and even instruments. They can handle drums and electric guitars through amplifiers easily.

Dynamic microphones aren’t able to pick up sounds that are distant, which isn’t a bad thing at all. Therefore, they’re more suitable for live performances since they can handle a lot of surrounding noise without picking every single thing up. On the other hand, if you’re looking for a studio microphone that is suitable, you’d rather want to get the condenser microphone type.

Ribbon Microphones

Ribbon microphones got the name from a very thin ribbon that is suspended in the magnetic gap. They come from the time when microphones used high impedance in the circuitry, so they’re considered to be quiet and kind of dark. They are very detailed without being too sensitive, but they need to be taken with a lot of care. They pick up smooth and warm sounds very well and they’re often used for guitar amplifiers, string instruments, drums, and even room microphones.

They might be an old-school type microphone, but they’re still used especially because of the way they were built before. The great thing is that they don’t require a phantom power and they come in different sizes as well.

Microphone Categories

Microphone categories are often mixed with microphone types, and you should make sure to get it right. There are only 3 types, yet there are more than 10 categories. They’re often categorized by different factors such as diaphragm sizes, size and way of use, connectivity type, and even pick-up pattern.

You don’t need to know all, but it’s useful to know what are the most common microphone categories since they can make choosing the right microphone easier, especially if you don’t know much about the microphones. They can also be categorized by the intended use as well, and many other ways which might be less important along these categories we have listed below.

Large Diaphragm

Whenever you notice the word large in the description of the microphone, it is telling you that the actual size of diaphragm is large. Large diaphragm microphones were the first size that actually came, back with the condenser microphone types. The main advantage of the large diaphragm microphones is their noise performance.

They are great at making the sounds bigger, better, more responsive to louder sounds, and are kind of better engaging. Recording quality large diaphragms provide sound very similar to the record recordings. Therefore, large diaphragms are used for both vocals and instrumental recordings. They’re very good at putting the vocal or instrument right in the spotlight. They’re very often used for recording lead instruments and studio recordings because of their advantage.

Medium Diaphragm

Usually, there were only large and small diaphragms, but recently even medium diaphragm has started its own category. However, not everyone, especially professionals will agree on its size when it comes to the professional recordings. On the other hand, they’re still good at picking up the high frequency and transient sounds. It picks up the sounds in a very similar to small diaphragms, however, there are some differences.

Medium diaphragm tends to deliver a slightly fuller and more round sound that is also potentially warmer. That just shows how medium diaphragm features some pieces and features from both small and large diaphragm, but just in a little bit of a different way. They’re very suitable for recordings where you would prefer to use both large and small diaphragm.

Small Diaphragm

Small diaphragms are widely used for picking up pure and natural sounds, without adding anything to them. There is less coloration in the sound, and that’s how it produces the most natural sound out there. Such advantage of small diaphragm makes them very versatile and they can be used for literally anything. There is no other diaphragm size that could potentially deliver you a more detailed sound.

They do a very good job at picking up the transient and high-frequency sounds, with a little bit of “air” effect to the sound. Small has its advantages as well, which in some cases might be better than large. Since they’re small, they can pick up and follow the sound waves closely without catching any disturbances along the way.

Lavalier Microphones

The small microphones that you can often see during the TV interviews or public speaking are called lavalier microphones, and they’re also very known as clip mics. They most of the time come with a wire and they come with the clips which help to attach them to the clothes.

Sometimes the wire may be hidden by the clothes, or in some cases, lavalier microphones can be used as wireless microphones thanks to the radio frequency transmitters. They offer a various range of frequency lengths and boosts which makes them very suitable for amplifying the voice recordings, such as the interviews. Therefore, they’re a great substitute for handheld microphones in some cases.

Handheld Microphones

They’re the most common and known type of microphones. They’re pretty easy to spot and differ from any other microphone category. Handheld microphones come in different types, and therefore, they’re used for many different purposes. So you will be able to see handheld microphones used for interviews, vocal recordings, instrumental recordings, YouTube video voiceovers, podcasts, and other. Their intended use is not limited since there are many different types.

They can be either wireless or wired, depending on the type, and they’re very suitable for both studio and live performances. Handheld microphones might look all the same at the first look, but there are major differences inside that is related to the parts and the way they work. They differ in the type and polar pattern.

Headset Microphones

Headset microphones are the two-in-one type of device that comes with both microphone and headphones. They’re very easy to recognize and they’re used for many different purposes such as gaming, voice chatting, voiceovers, podcasts, and many other.

They can be either wireless or wired to either 3.5 mm jack or USB port. They’re not very suitable for instrumental recordings, but they’re perfect for voice recordings which allow the use of the microphone without holding it. It’s placed very close to the mouth which is great for two reasons. It picks up very little surrounding noise, and it’s always there to your mouth without any stand that might take space on your desk.

Worth to mention, it might be obvious that headset microphones aren’t suitable for professional vocal recordings either.

Boundary Microphones

Not many people understand boundary microphones. They’re very small microphones which are usually condenser omnidirectional microphone type. They’re supposed to be positioned near the boundary. It can record things such as piano, a full room of people when it’s being mounted on a wall. They can even record solo artists or small musical performance.

If you have ever watched a hockey game, when a player gets smashed into the barriers, the sound that is projected to the audience is captured right with the boundary microphone that is placed on the barriers’ wall. They reflect the sound in a natural way with a flat frequency response.

USB Microphones

USB microphones are just like any other type of microphones, yet they have one big advantage. Their electrical energy is transferred into the digital output for digital recording purposes. They also come in many different types, shapes, and sizes. Therefore, they are used for many different things. They’re suitable for studio recording, live performance, voice chatting, gaming, podcasts, and other.

They have a wide range of intended use, however, it solely depends on the type of the USB microphones. They always come wired and connect with any computer or device that supports USB connections. Most of the time, they don’t even require any installation, which makes them very suitable for recording on a go. They’re as good as a handheld or any other microphone type, and you will recognize them only by the USB port cable.

Shotgun Microphones

Shotgun microphones are most of the time unidirectional microphone type which means that they pick up the sound very well when the sound is right in front of the microphone, however, it has troubles picking up sounds that are far away from it.

In case you’re wondering, the shotgun name came from the design which looks exactly like a barrel of a shotgun weapon, and its use which requires the microphone to be pointed exactly at the sound source. They’re often used in speeches or talks in conferences, meetings, or even lectures. They’re a great substitute in case the speaker doesn’t or can’t hold the microphone or have it attached to his clothes or body. They’re used for simple voice recordings and aren’t suitable for other purposes.

Bass Microphones

Just as the name says, bass microphones are specifically designed microphones that can record bass well, whether it is a bass guitar or a drum bass. The electric bass is part of the sound that might create problems for other types of microphones, yet bass microphones are specially created to record such sounds.

They’re most of the time wired microphones that either record the sound from the console or pre-amplifiers, or through a bass amplifier. Therefore, they’re not suitable for vocals at all. However, they can be used for a live performance of bass instruments. It’s not the most known microphone category, but it’s definitely known to people who need a tool to record their bass.

Multi-Pattern Mics

As you probably know, each microphone has its type and has its pickup pattern. They help the users in recording specific sounds and such types and patterns help to produce the most quality recording sounds for various intended purposes. However, when you need to have more than pick-up pattern to switch between, multi-pattern microphones are useful.

Instead of getting two or three different pattern microphones, simply get a multi-pattern microphone that will do the job of three different pattern microphones. They’re suitable for both instrumental and vocal recordings since they have more than one pickup pattern. They can either be wired or wireless and are suitable for many different purposes. You can think of them as a pretty universal microphone.

Polar Patterns Explained

As there are microphone types and categories, there is also something called polar pattern. Polar patterns determine the way microphone picks up the sound. Polar patterns are important because each pattern has its advantages and disadvantages, and is suitable for different purposes.

While there are two or three most common polar patterns, we will explain you all polar patterns out there. It’s not hard to understand how the patterns work once it’s explained in a simple way like down below. But learning how each pattern works and what is it most suitable for can help you a long time in choosing the right microphone that will match your needs.

Omnidirectional

A simple way to understand how omnidirectional pattern works would be to think that omnidirectional polar microphones hear everything around them and they easily pick it up. They’re equally sensitive to all directions and therefore, they’re suitable for instrumental recordings such as orchestra recordings.

Often, they’re used in home studios for acoustic instruments such as guitar, or to record background vocals. They can basically pick up anything that is in the ambiance of the room. Omnidirectional polar patterns are usually combined with condenser microphone types which create a perfect combination. They are able to pick up everything that is going on around them without a problem.

Cardioid

Cardioid polar microphones are also known as microphones that don’t only hear, but also listens. The cardioid polar pattern is the most sensitive microphone pattern out there. It’s the most sensitive to the sounds that are coming from the front, while the sounds that are coming from the sides are picked up in a quieter way. Just like the omnidirectional pattern – the sound from the rear is rejected and eliminated.

Cardioid polar microphones are most used for recording vocals. In a theory, they’re suitable to record anything that is supposed to sound “close” and “dry”. It’s not unusual to see that most of the microphones feature cardioid polar pickup pattern. In my opinion, it’s one of the most universal and the most used polar patterns.

Supercardioid

Supercardioid can be considered to be a “brother” of the cardioid polar pattern. While cardioid polar pattern picks up the sounds from the sides and front, while rejecting the rear, supercardioid does a really similar thing. But there is one big difference.

Supercardioid polar pattern narrows down the pickup area and kind of reject the sound from the sides. Therefore, the head of the supercardioid microphone will be the most sensitive part. You can think of supercardioid microphones as more focused microphones. Therefore, they’re suitable for the conferences, interviews, and voice recordings where you want to eliminate the surrounding noise. They’re suitable even for the live stage performance since they’re good at eliminating the noise from the ambient.

Hypercardioid

If you take a supercardioid polar pattern and upgrade it to narrow the pickup area, you will get a haypercardioid polar pattern. It works the same way as cardioid or supercardioid polar pattern does. However, it narrows, even more, the pickup area and therefore, it’s less sensitive to the sounds.

It doesn’t pick up the sound from sides or rear, yet only from the front. Since it’s the least sensitive cardioid polar pattern, it’s very great at eliminating the surrounding noise, no matter how much noise is there around you and the microphone. They’re frequently used in situations where the noise is needed to be eliminated completely between the sound source and the microphone. They can be used for both vocals and instrumental recordings, and are made for live performance.

Shotgun

The shotgun polar pattern is very similar to the hypercardioid pattern, yet it’s considered to be even less sensitive. It works the same way rejecting the unwanted sounds from the sides and rear while focusing all its sensitivity at the front. Shotgun microphones have its own shotgun polar pattern that helps to pick up the sound that is distanced which can’t be approached with a handheld or any other microphone.

Or they can be used when the speaker doesn’t have the opportunity to hold the microphone himself or has it attached to him. It’s most suitable for vocal recordings, for example during interviews or speeches. It’s not recommended for other types of use. You can think of shotgun polar pattern which is used only when it’s necessary.

Subcardioid

Subcardioid is another type of cardioid polar pattern, but it works in a different way than any other previous pattern. They pick up the sounds from the sides mostly, while also from the front. It’s kind of a mix between the omnidirectional and cardioid pattern.

The sound of subcardioid polar pattern microphones is very natural and open and it’s even suitable for the performances where the stage volume is low. However, there is one downside. They’re very prone to the feedback and noise. Subcardioid is also known as wide cardioid which is very suitable for recording a group of vocals or instruments.

Bi-directional or Figure Eight

The Bi-directional polar pattern is also known as figure eight, and there’s a reason for that. It’s able to pick up the sound from both front and rear of the microphone, and if you imagine a number 8 on top of the microphone, that’s the area it picks up the sound.

From a difference than any previously seen polar pattern, bi-directional rejects the sounds from the sides. This pattern is mostly seen with the ribbon microphones. They’re very suitable for recording two voices at the same time so it’s great for vocals with more than one singer. It’s a perfect polar pattern for a singer who’s also a guitar player.

However, such pickup pattern from both front and rear might give you some trouble with noise. You must always remember that it picks up the sound from behind, so remove anything that can make noise behind the microphone and you won’t have any problems.