Microphones & Stands
Professional sound technicians know that choosing the right microphone is an essential part of any good recording.
However, for those new to the world of recording technology, the topic of microphones is likely shrouded in mystery. With a bit of studio experience, you'll learn that certain studio microphones work well for recording specific instruments, but without an understanding of acoustic theory, you probably won't grasp why.
Should you opt for a dynamic or a condenser microphone? Tube or solid-state microphone? The selection of studio microphones is so vast that a basic understanding of microphone types and their applications can be helpful. A poor microphone choice typically stands out in the mix - but don't worry!
Our microphone buying guide decrypts the secrets of microphones and sets you on the path to fantastically sounding recordings.
Types of Microphones
Dynamic Microphones
In a dynamic microphone, the audio signal is generated through the movement of a conductor within a magnetic field. In most dynamic microphones, a very thin, lightweight diaphragm moves in response to sound pressure. The movement of the diaphragm sets a suspended coil in motion within a magnetic field, thereby generating a small electric current.
Dynamic microphones are less sensitive (to sound pressure levels and high frequencies) than condenser microphones and can generally withstand more. Additionally, they are usually more affordable.
Dynamic microphones are perfect for recording drums and electric guitar as well as live vocals. The most popular snare microphone of all time is the legendary Shure SM57 (also suitable for guitar amplifiers), which still finds a place in studios and stages worldwide.
Condenser Microphones
If you're concerned about absolute fidelity of sound, you should opt for a condenser microphone. Condenser microphones respond better to the "speed" and nuances of sound waves than dynamic microphones. This simple mechanical system consists of a thin, stretched, conductive diaphragm, which is closely attached to a metal disc (backplate).
This arrangement creates a capacitor that gets its electric charge from an external voltage source - a battery or phantom power supplied by your mixer.
The microphone diaphragm vibrates slightly in response to sound pressure, thereby altering capacitance and producing a voltage change - the microphone's signal output. Condenser microphones are available as both solid-state and tube microphones and in a variety of shapes and sizes - but they all operate on this principle.
Especially in the studio or in radio stations, condenser microphones are almost always found, as they are sonically superior to dynamic microphones.
Ribbon Microphones
In the golden age of radio, ribbon microphones were the first commercially successful directional microphones. Today, thanks to the efforts of a handful of companies like Royer, ribbon microphones are making a comeback. Ribbon microphones respond to the speed of air molecules, moving a small element suspended in a strong magnetic field, and not to sound pressure level (SPL) that excites most other types of microphones.
In studio applications, this operational difference is not significant, although it can be critical during outdoor recordings on a windy day! Old ribbon microphones were very delicate; today's ribbon microphones are designed to withstand the rigors of the studio environment.
USB Microphones
The USB microphone is a more recent development in microphone technology and includes all the elements of a traditional microphone: capsule, diaphragm, etc. What sets it apart from other studio microphones are two additional circuits: an integrated preamplifier and an analog-to-digital converter (A/D).
The integrated preamplifier eliminates the need for the USB microphone to be connected to a mixer or an external microphone preamplifier. The A/D converter converts the microphone's output from analog (voltage) to digital (data), allowing it to be directly connected to a computer and read by recording software.
This makes mobile digital recording as simple as plugging in the microphone, starting the DAW, and pressing the record button!
Reading and Interpreting Frequency Response Diagrams
The frequency response diagram of a microphone can tell you a lot about which situations are suitable for a particular microphone and which are not. Theoretically, the frequency response diagrams are created in the factory by testing the microphones in an anechoic chamber.
An anechoic chamber is a specially designed space used only for audio testing. The idea is to create a controlled atmosphere where each microphone can be tested equally, so that the space is completely dead, without any form of sound reflection.
Typically, a speaker is placed in front of the microphone under test and pink noise is played (pink noise is all frequencies with equal energy in each octave). The microphone is then routed to a spectrum analyzer that measures the output and creates a frequency response diagram.
Usually, the diagram covers the range from 20Hz to 20kHz, which corresponds to the range of the human hearing.
But how do you read it?
The horizontal numbers in a microphone frequency response diagram represent the frequencies (usually in the range of 20 Hz to 20 kHz), and the vertical numbers represent the relative responses in dB (decibels). Looking at a frequency response diagram, you can see how a particular microphone performs at certain frequencies. How is this information helpful? Well, let's look at the frequency response diagram of the famous Shure SM57:
The frequency response of the SM57 microphone is particularly suitable for specific instruments such as a snare drum, as the fundamental frequency of the snare drum is in the range of 150Hz to 250Hz - exactly where the SM57 frequency response diagram shows that the SM57 response is flat or neutral. In other words, at this frequency, what you hear in the microphone is also what you will hear at the output - neither more nor less.
The bump in frequencies on the right side of the diagram is where the frequency of the snare's "snap" lies. Additionally, the microphone with its attenuated bass range is excellent for accentuating the kick drum, which is often very close. This combination is what most sound engineers look for in a good snare drum microphone - the ability to capture the true sound of the snare, accentuate its snap, and reject other instruments nearby.
The Different Microphone Polar Patterns
Cardioid
Microphones with cardioid polar patterns capture signals best in front of them while rejecting sound from the sides and rear. The graphical representation of the polar pattern resembles a heart (hence "heart-shaped"). The ability to suppress sound from the rear makes the cardioid pattern useful in situations where multiple microphones are used and where it is not desirable to capture a large amount of ambient atmosphere.
Cardioid microphones are popular both in the studio and in live performances (where rear sound suppression reduces feedback and ambient noise) and are used for a very high percentage of microphone applications. Note that cardioid microphones, like all microphones without cardioid pattern, exhibit a proximity effect (increased bass reproduction when the microphone is very close to the sound source).
Supercardioid and Hypercardioid
The supercardioid polar pattern is even more forward-directed than the cardioid, while the hypercardioid is even more so. Unlike the cardioid, both polar patterns have sensitive rear areas (smaller in the supercardioid), which pick up sound, making the positioning of these highly directional microphones somewhat challenging.
Omnidirectional
Microphones with omnidirectional polar patterns capture sound from all directions equally. The graphical representation of the polar pattern is a circle. A microphone with an omnidirectional polar pattern does not have a pronounced proximity effect. Initially, all microphones are produced with omnidirectional characteristics. The polar pattern is then achieved through additional technical measures. Omnidirectional microphones are great studio microphones for capturing ambiance along with the recording.
Figure-8 Pattern
A figure-8 polar pattern is a shape where the microphone is equally sensitive to sound coming from the front and back but rejects sound coming from the sides. This results in a polar pattern that looks like an "eight," with the microphone capsule located at the intersection of the 8. This microphone characteristic is also referred to as bidirectional.
Multiple Polar Patterns
Many professional condenser microphones have switchable polar patterns. Typically, the polar patterns are cardioid, omnidirectional, and figure-8, allowing the microphone to flexibly adapt to the appropriate recording situation.
Differences in Microphone Diaphragm Sizes
Condenser and dynamic microphones are classified based on the size of their capsule. Traditionally, this has led to two classes: large-diaphragm and small-diaphragm microphones; both have their place in a well-equipped studio. The medium-diaphragm microphone - a relatively new development - can be considered a hybrid that combines the characteristics of large and small diaphragm microphones.
Large Diaphragm
Large-diaphragm condenser microphones like the venerable Neumann U87 are a staple in the studio. From vocals to strings and brass to percussion, practically anything can be recorded with large-diaphragm condenser microphones . The diverse pickup characteristics found in many large-diaphragm condenser microphones make them the most versatile microphones in the studio. There are also dynamic large-diaphragm microphones that work well for recording loud sources with powerful lows (e.g., kick drum or toms).
Medium Diaphragm
The definition of medium diaphragm is a potentially controversial topic. Historically, there were large-diaphragm and small-diaphragm microphones, but recently the medium size has begun to form its own category, although not everyone agrees on the exact upper and lower limits. Most professionals and manufacturers agree that any microphone with a diaphragm of approximately 5/8″ to 3/4″ in diameter can be referred to as medium diaphragm. Generally, microphones with medium diaphragms tend to capture transients and high frequencies well (as a small diaphragm would), while delivering a slightly fuller, rounder, and possibly warmer sound (as a large diaphragm might).
Small Diaphragm
Small-diaphragm condenser microphones, often seen by novices in the shadow of large-diaphragm microphones, can indeed shine in applications where their larger siblings cannot compete. Their characteristic extremely fast response times are attributed to their smaller, lighter diaphragms. As studio microphones for acoustic guitar, hi-hat, harp - or any other instrument with sharp transients and extended harmonics - small-diaphragm microphones are the first choice for many sound engineers as drum overheads. The advantage of these lightweights (often referred to as pencil microphones due to their typically thin cylindrical shape) is that they can be easily positioned.