Today we are going to talk about the four different types of microphones used in music studios, what the differences between each of them are and when each is used.
If you’re here because you’re trying to choose between the types, a good rule of thumb is—
If a microphone is to be used in a harsh environment, such as a club, or an outdoor setting, use a dynamic microphone. If the environment is more controlled, such as a studio, a condenser microphone should be preferred, especially when the highest sound quality is desired. If you want to have a natural sound in recording (like what your ears hear in a room), tame harshness, or isolate a particular sound source, use a ribbon microphone.
Let’s dive right in.
Types of Microphones
The four types of microphones are—
- Dynamic Microphones
- Large Diaphragm Condensor/Capacitor Microphones
- Small Diaphragm Condensor/Capacitor Microphones
- Ribbon Microphones
The words dynamic and condenser describe the operating principal used in a microphone. The operating principle refers to the type of transducer (how the mic picks up sound and converts it to an electric signal) inside the microphone.
In engineering, a transducer is a device that converts a signal in one form of energy to a signal in another. In our case, acoustic to electrical energy.
Dynamic microphones use a diaphragm, voice coil, and magnet assembly which forms a miniature sound-driven electrical transducer. That is why they are also called moving coil microphones.
The sound strikes a plastic membrane (the diaphragm) which then vibrates with a wire (the voice coil) attached to the rear.
The voice coil is surrounded by a magnetic field created by a small permanent magnet. The motion of the voice coil in this magnetic field generates the electrical signal.
Dynamic microphones are much simpler in construction, more economical, and more rugged than all other types of microphones.
They are known for excellent sound quality in all areas of microphone performance.
They can handle extremely high sound levels particularly well because it is almost impossible to overload them.
They are relatively unaffected by extremes of temperature and humidity.
They are the most widely used.
Perhaps two of the most popular dynamic “budget” microphones are the Shure SM57 and the Shure SM58. The Shure SM57 is a staple in home and pro studios alike.
If you’re on a budget, say USD$ 100, and can only buy one mic, one of these is where you’ll likely end up.
Further up, say with a USD$500 budget, the Shure SM7B is a good choice.
One great thing about using a dynamic microphone to record vocals in a room with bad acoustics is that you don’t pick up a lot of room noise.
When people think of studio microphones, usually, they are probably thinking of some type of condenser mic.
Condenser microphones are based on a sound-sensitive capacitor (an electrically-charged diaphragm/backplate assembly). They are also known as capacitor microphones.
Sound waves vibrate a very thin metal or metal-coated-plastic diaphragm mounted in front of a rigid metal or metal-coated-ceramic backplate.
This assembly is historically called a condenser, hence the name. It can store a charge or voltage.
When charged, an electric field is created between the diaphragm and backplate proportional to the space between them. It is this variation in space that produces a corresponding electrical signal in a compressor microphone.
A condenser microphone must maintain an electrical charge or polarizing voltage.
An *electret condenser microphone has a permanent charge, maintained by special material on the backplate or diaphragm. A non-electret condenser microphone is charged by an external power source. Most condenser microphones are electret.
All condenser microphones contain additional active circuitry to allow the electrical output of the condenser to be used with typical microphone inputs. This requires all condenser microphones to be powered either by batteries or phantom power.
The wires have to be very short in a capacitor mic because the impedance of the capacitor is very high. Any wires longer than a couple of inches would degrade the audio signal.
But this additional circuitry has two limitations—
- The electronics produce a little noise. Condenser mic specs will include a noise level.
- There is a limit to the maximum signal level that the electronics can handle. Condenser mic specs will include a maximum sound level.
A good condenser mic will have very low noise levels and will be capable of a very wide dynamic range.
Condenser microphones are more costly and complex than dynamic microphones.
They may be adversely affected by extremes of temperature and humidity causing them to become noisy and fail temporarily. They are more fragile (so don’t drop them).
They have higher sensitivity, providing a smoother, more natural sound at higher frequencies.
Large-diaphragm condenser mics are great for recording vocals, anything that has a lot of nuances or dynamic range.
Because they are higher sensitivity, unlike dynamic microphones, condenser microphones will pick up room noise.
Flat frequency response and extended frequency range are much easier with a condenser mic.
You can use them as room mics in front of drums, or even to record an entire band.
They can be made small without significant loss of performance.
Ribbon microphones have been around since the 1920s. They are the earliest types of microphones that were commercially available.
A ribbon microphone is very simple.
There is a thin strip (ribbon) of conductive material, typically a low mass metal like aluminum, suspended inside a magnetic field.
The ribbon moves back and forth in response to sound waves inducing an electrical current.
To increase durability and also to improve the frequency response of the microphone, the ribbon is typically corrugated.
By design, most ribbon microphones have bi-directional polarity — a figure 8 pickup/polar pattern.
This figure 8 polar pattern makes them pick up equally well from the front and the back. And they have natural off-axis response meaning they sound consistent as you move around the polar pattern.
Sound entering from the front or the back of the mic causes the ribbon to move back and forth but sound entering from the side doesn’t cause the ribbon to move.
This means there a deep null on the side of the polar pattern and very effective isolation for rejecting sound sources.
Because of the ribbon construction, a ribbon microphone has resonant frequencies above the range of human hearing. This means that the detail and high-frequency response is extremely accurate.
Ribbon microphones are described as sounding the way our ears hear. Ribbon microphones are more natural sounding than dynamic microphones.
Because the ribbon is an extremely low mass, with high-frequency detail, ribbon microphones have extremely good transient response. They are extremely accurate on transients, meaning they don’t overshoot like some condenser microphones do.
Older designs of ribbon microphones were quite delicate, but the modern ones are sturdy even at high-pressure levels and you can use them in just about any situation.
Ribbon microphones have a very strong proximity effect. This means that when you get close in you’ll get a big bass boost.
One thing you have to be careful about with ribbon microphones is gusts of wind or bursts of air hitting the ribbon. That can cause the element to stretch out changing the frequency response and the sound of the microphone.
You want to protect a ribbon microphone with a pop filter if you have a vocalist in front of it, and if you have it in front of something like a drum set or kick drum, you want to angle the microphone so it’s not getting directly struck by a blast of air.
If you are outside in the wind, you want to use some sort of wind protection.
Passive vs Active Ribbon Microphones
There are two basic types of ribbon microphones—
- Passive ribbon microphones.
- Active ribbon microphones.
A popular example of a passive ribbon microphone is the R-121 Studio Ribbon Microphone by Royer.
A passive ribbon microphone means that the ribbon element passes through a transformer before being sent to a mic preamp.
Generally, passive ribbon microphones are fair low output. This means you need to connect them to a preamp that has good, clean gain so you’re not getting noise added into the signal.
A preamp that also allows you to adjust the impedance can let you tailor and shape the sound of what’s coming out of the mic as well.
An example of an active ribbon microphone is the AEA N22.
An active ribbon microphone means that it has built-in electronics. Those electronics serve two purposes—
- They isolate the ribbon microphone from the preamp to avoid impedance issues.
- They boost the gain up to avoid noise issues.
Both passive and active ribbon microphones work and sound great.
Traditionally, you use a ribbon microphone on brasswind instruments such as the trumpet and the trombone, on woodwind instruments such as the saxophone and the flute, and the electric guitar.
This is because the ribbon microphone tends to smooth out the harshness of these instruments. Ribbon microphones are great for taming harshness.
Ribbon microphones are good as overheads on a drum kit or a stereo pair on a piano, you can even use them for vocals (traditionally, jazz vocals with a rich round natural tone).
Ribbon microphones are very versatile microphones.
When using a ribbon microphone for isolating a particular sound source a great trick is to use a pair of ribbon microphones for stereo recording in a bloom line configuration.
A bloom line configuration means one above the other at 90 degrees so you’re picking up the room from behind in a stereo image of the direct sound in front.
You should be having a pretty good idea of the types of microphones now.
I’ve spoken extensively on each of these types of microphones elsewhere on this blog. Have a look around for a specific type you’re interested in.
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That’s it for this article.