My aim with this article is to provide you with a one-stop resource to have all your microphone questions answered.
You'll learn about the different types of microphones and the best use cases for each. This isn't meant to be a static guide, rather I will be updating as required so feel free to mention any tips in the comments below!
There are a number of different types of microphones available to us. It's not going to take an engineering degree to have an adequate understanding of each type.
Why is this important? Each different type of microphone will have characteristics that will enable it to handle sound in ways that will either be beneficial or detrimental to your audio recording. Knowing these characteristics will ensure you use the correct mic for the correct recording situation.
How Do Microphones Work?
Microphones essentially are transducers. They transfer one type of energy into another. In this case it's acoustic energy (sound waves) to electrical energy (audio signal). They use the exact same principles as loudspeakers, just in reverse!
As you may know a loudspeaker works by flowing electricity through a metal coil that is wrapped around a permanent magnet. The flowing electricity through the coil creates a magnetic field that is resisted by the permanent magnet. This forces the coil to move. As the coil is attached to a diaphragm the diaphragm is also moved. The moving diaphragm is what transfers the electrical energy into physical acoustic energy (sound waves).
A microphone uses the exact same principle, just in reverse!
Condenser microphones are slightly different. We will discuss how they work in the condenser section below!
When you speak you create sound waves in all directions. Every instrument works in a very similar way - sound waves are created and travel through the room. Inside the microphone is a small diaphragm (much smaller then in most loudspeakers). The sound waves cause this diaphragm to be displaced. As the diaphragm moves, the coil wrapped around the magnet also moves.
The coil is moved through the permanent magnetic field created by the stationary magnet. This in turn creates an electrical signal that can be amplified and transmitted.
The electrical signal from the microphone can either be recorded, amplified, or sent to a loudspeaker. You can store the sound forever as an audio file and reproduce it again with speakers using the same (but reversed) principles!
Microphone Polar Patterns
Before we jump into the different types of microphones, I'd like to quickly cover one more basic concept - polar patterns. The polar pattern of a microphone can be thought of as how the microphone "hears" sound from different directions. In other words, the sensitivity relative to the direction or angle from which the sound arrives.
The most common types of polar patterns are Omnidirectional, Cardioid and Supercardioid, and Figure-8.
Cardioid Polar Pattern
The cardioid polar pattern is the most common polar pattern used with microphones. This polar pattern captures everything directly in front of the microphone and blocks everything from the back.
It is great for isolating any unwanted sounds and is very resistant to feedback. This makes it very suitable for loud stages. Cardioid mics are widely used for live performances from huge stadiums to karaoke performances.
They can also be used to mic any sound sources that have high sound pressure levels such as drums or amps.
As the name suggests, the omnidirectional polar pattern has equal sensitivity in all directions. Because it has zero rejection, it is great for capturing the natural sounds within the room. This is a common type of polar pattern found in lavalier microphones.
If you have a large room and you want to capture the unique acoustics this would be a good option. The obvious downside is you are unable to point the microphone away from any unwanted sound.
The supercardioid polar pattern offers narrower pickup compared to the regular cardioid. The also have some pickup coming direction from the rear so be careful with monitor placement.
The greater restriction results in more ambient sound rejection. These mics are intended to be used in loud environments (stages etc.). They can also be great for untreated recording studios.
These microphones pick sound from the front and rear but reject any sound from the sides. These are used to capture two instruments at once and are typically found in ribbon or large diaphragm microphones.
While not as common as the cardioid polar pattern, they can be great for recording any audio in stereo. If you want to record dual vocals this polar pattern is also a great option.
Size matters. The size of your microphone diaphragm is going to play an important role in determining the strengths and weaknesses as well as the application of the microphone. Large diaphragms (also called membranes) are typically 1 inch or more in diameter. Small diaphragms are usually less than 1/2 inch in diameter. Just use this a rule of thumb. You will definitely find microphones breaking these guides.
The size distinction is usually only applied to condenser microphones. Small diameter condenser microphones are usually pencil shaped whereas large diameter diaphragms are often much larger. Small diameter microphones only became feasible with the creation of low-noise transistors (1950s to 60s).
Large diaphragms capture much more acoustic energy and will generate a higher signal voltage. Small diameter microphones will have better transient response, better high-end frequencies, and maintain a very consistent pickup pattern.
The smaller size of the small diameter allows it to maintain a consistent polar pattern over the entire range of frequencies. The downside to a large diaphragm condenser microphone is that the low-end remains lush even if the audio purposely raises in frequency.
Large diameter condenser mics came first. Early versions of the condenser microphones had to use large diameter capsules to overcome the noise of the tube electronics. Things became much easier with the invention of semi-conductors.
Small diameter microphones are best used if you want to capture the natural sound of the audio without any added color. They will have the best chance of recording a neutral sound and are often used for piano, acoustic guitar, stringed instruments, drums and percussion. You definitely need to use a small diameter mic if you are recording classical music.
- For recording natural sound.
- Uncolored, neutral, detailed sound image.
- Makes the sound bigger and more engaging.
- Perfect for vocals.
One of the most common styles of microphones. Most of the microphones you will see in everyday life will be dynamic microphones. This is primarily due to their ease of construction, low price and high durability. They use the simple construction mentioned in How Microphones Work section above.
As a rule of thumb, dynamic microphones should be used for high sound pressure levels (SPLs) and things in the mid to low frequencies levels. They are also perfect for use in loud environments such as stages or recording studios.
Example use cases include:
- Stage vocals.
- Guitar amps.
- Untreated recording studios.
- With a PA.
Because there is no internal circuitry (as in condenser microphones) dynamic microphones do not require a phantom power source. This lack of circuitry means the diaphragm of the microphone can be much more durable - thus the dynamic microphone can be used at high SPLs without the worry about damage.
Another reason dynamic microphones are so popular for onstage use is they are extremely resistant to environmental changes. Whereas large swings in humidity can damage a condenser microphones internal components, dynamic microphones have a very simple construction that is extremely durable.
The heavier diaphragm has another benefit - it is far less sensitive to feedback. Just another reason dynamic microphones are the preferred microphone for live performances.
Another benefit of dynamic microphones is their cheap price tag. Because they are relatively simple to construct, companies can offer them at much more reasonable price ranges.
- Not as detailed as condenser microphones.
- Not the best for high end frequency recording.
The other most common microphone: the condenser. This style of microphone is hugely important for recording studios or DIY musicians. For reasons that will become evident soon, you are typically able to record much more detail with a condenser microphone.
Condenser microphones take a slightly different approach compared to dynamic microphones in terms of their method of changing acoustic energy to electrical energy. A condenser microphone uses a capacitor instead of a magnet and coil. A capacitor is a device that stores energy in the form of an electrostatic field. They are found in almost every type of electric equipment.
In a condenser microphone the diaphragm acts as one plate of the capacitor. This very light material vibrates as it is hit with sound waves changing the distance between the two plates. This changes the capacitance of the capacitor and thus an electrical signal can be created. A capacitor requires a voltage to be applied across the capacitor, hence the need for a phantom power source.
The diaphragm material can be incredibly light - thus allowing the condenser mic to pick up on much smaller sound waves compared to a dynamic microphone. The sensitivity of the condenser mic also comes with a number of downsides.
Small diameter condenser microphones are often operated end-fire while large diameter microphones are usually much bigger and are operated side addressed.
Firstly, as they are much more complicated to manufacture, they tend to be more expensive than their dynamic counterparts. The internal electronics are also very sensitive and can be easily damaged from large changes in humidity or any large impacts (say from dropping from the mic stand).
These electronics also require a constant power source (phantom power) which can make them impractical to use for any portable recording. This can also be an issue if you are trying to power your condenser off of your tablet (with a USB condenser mic for example). These devices won't be able to output the power required to drive the internal electronics, thus you will end up with an underperforming microphone.
High SPLs can also be damaging to a sensitive microphone so it is not recommended that you use them for recording loud instruments.
So why are they so popular if they have so many issues? One word: fidelity. Condenser microphones can be much more detailed due to the lightweight diaphragm. They are heavily used in recording studios or those looking for detailed recording for podcasting. The level of detail you can record is worth putting up with all the high maintenance!
Example use cases include:
- Acoustic instruments.
- Studio vocals.
Condenser mics usually come in two flavors: large diaphragm and small diaphragm. Use large diaphragm for any detailed recording while using the small diaphragm mics for recording any detailed high-end shimmer.
- Require a power source.
The ribbon microphone used to incredibly popular in the radio industry. They have been making somewhat of a comeback due to their unique recording quality. Instead of using a diaphragm they use an aluminium ribbon. The ribbon allows the microphone to pick up the air's velocity along with the displacement from the sound pressure.
They are more durable than the condenser microphone but they are still able to record in high detail. They do particularly well when recording higher frequency sounds. They also typically come with a figure-8 polar pattern - perfect for multi-instrument recording.
Modern ribbon microphones are now built to be more reliable as well as sturdy. Pick one up if you are looking to get a unique vintage sound or want to have a unique live experience in a room with moderate sound levels.
Example use cases include:
- Vocal recording.
- Multi-instrument recording.
- Not the best for multi-purpose recording.
Lavalier microphones are small microphones typically used for applications where hands-free is required. They clip onto your collar and are usually small enough to remain out of sight. The cord typically runs from the microphone to a radio frequency transmitter clipped to a belt. You may also hear this microphones called "lav" mics or "lapel" mics.
They are typically used for television, public speaking, with a DSLR camera, interviews, podcasts, and in theater. In essence, they can be used for anything that requires a small mic that can be hidden easily. Your main concern with a lav mic is whether or not you are going to need wireless. Wireless mics usually cost much more and have limitations when it comes to battery life.
Example use cases include:
- In conjunction with a DSLR.
- Public speaking.
Most high-quality lav mics will use a condenser capsule. They will commonly use an omni-directional polar pattern to have the best change of capturing the speaker at odd angles. Make sure it comes with a wind-shield.
- Limited by battery life.
- Can be expensive for good-quality.
Portable Microphones (X/Y Microphones)
Another microphone worth mentioning is the increasingly popular portable microphone. These microphones are designed to connect directly to your smart device to provide a convenient way to record without having to carry around an additional recording device. You can actually get a respectable sound using these microphones at a reasonable price.
X/Y microphones are usually the most popular as they offer the most versatility for field recording. A stereo image is created using two condenser microphones placed at 90 degrees with respect to one another.
Because they are designed for close proximity they will have a reduced low-end if you attempt to record at large distances.
Example use cases include:
- Field recordings.
Make sure you check the compatibility of the microphone before you purchase it. There are some that are specifically designed for use with an iPhone and you will have difficulty using it with any other device.
One of the main benefits of these microphones is the simplicity. If you buy the correct microphone any compatibility concerns or power issues go out the window. Most are designed to directly interface with the device software and make any integration a breeze.
- Limited by battery life.
- Not hands-free.
I hope this was a good first introduction into the world of microphones. If you have any questions please feel free to leave them in the comment section below. Additionally, if you have any other pieces of advice that your fellow readers may find useful please post it below!
There is still much to learn when it comes to microphones. Recording engineers usually have chests full of different microphones for each different recording situations. The above basics will give you a good idea of the best direction to head if you are purchasing your first microphone. Just remember, it's not the end of the world if your microphone doesn't exactly fit what you are using it for. Jump in and start recording!