Microphones buying guide
For home studio and live sound applications
Ralph Graves is one of Crutchfield's blog editors, and part of the company's social media team. He writes about home audio/video gear, specializing in Apple-related and wireless technologies. Ralph holds a master's degree in music composition, and his works have been released on various labels. He's served as product manager for an independent classical and world music label, produced several recordings, and worked extensively in public broadcasting. Since 1984 he's hosted a weekly classical music program on WTJU, and is also active as a blogger and podcaster.
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Selecting microphones can seem daunting for a first-time buyer looking at the wide variety of shapes, sizes, and prices. But the basic concepts behind microphones are pretty simple. Once you’ve determined what you’ll be using a mic for, selecting one to match your needs and budget can be straightforward.
Below is an outline of microphone types and how they’re most commonly used. With this information, you should find it easier to select a microphone that’s best suited for your needs.
What will you use this mic for?
There are two basic uses for microphones: studio recording and live performance. “Live performance,” of course, not only covers music venues, but also churches, school auditoriums, and other places where a voice or instrument has to be amplified to be heard clearly by an audience.
A Shure condenser microphone
Best for recordings — Condenser mics are extremely sensitive, and very accurate, making them the first choice for recording studios. Large diaphragm condenser mics are usually used to record vocals, while small diaphragm mics are better suited for instruments, such as the acoustic guitar. Small diaphragm condenser mics are sometimes used to in live music venues to mike cymbals, which can give them a clean, tight sound.
What they are — the diaphragm is one plate of a capacitor. As it vibrates, the changing distance between the diaphragm and the fixed plate create the signal. Because the diaphragm can move quickly, condenser mics are extremely sensitive and responsive. Condenser mics require an external power source. Usually this comes in the form of "phantom power," which is 48-volt direct current supplied by your mixer or audio interface and is carried via an XLR cable to the mic.
A Shure dynamic microphone
Best for live performances — Because of their extreme durability, dynamic mics can handle frequent setup and tear-down. For that reason, they’re great for live performances.
What they are — a small induction coil, attached to the diaphragm, creates a variable magnetic field that provides the signal. Dynamic microphones are often tailored for certain frequencies for specialized applications. The AKG Perception P4 dynamic microphone, for example, is designed for low instruments and has a frequency response of 40-18,000 Hz instead of the full 20-20,000 Hz.
How much do you want the mic to pick up?
Do you only want to record the sound of one guitar and nothing else around it, or the sound of the whole band in front of an appreciative audience? A mic’s polar pattern shows what sound sources it’s picking up. Some microphones allow you to change the pattern of the mic. Each of these three main patterns have their own advantages.
Cardioid — A diagram of a cardioids pattern looks like an inverted heart, with the mic at the point where the two halves curve in. A cardioid mic picks up mostly what’s in front of it, with very little from the side, and nothing from the back. This pattern’s most often used for mic’ing a singer, or a single instrument. Cardioid mics are also used in broadcast studios.
Cardioid polar pattern
Omnidirectional — an omnidirectional mic records everything in a 360-degree radius. These are used when you want the ambiance of the room mixed in with the sound source. It’s also useful if the sound source is changing position in relation to the mic, which is why camcorder mics are omnidirectional.
Omnidirectional polar pattern
Bi-directional — sometimes called a Figure 8. This type of mic picks up what’s in front of it and behind it equally, and nothing from the sides. Bi-directional mics are useful when two people have to share a microphone — such as an interview, or two singers.
Bi-directional polar pattern
How a microphone responds to changing air pressure is called its sensitivity. Highly sensitive mics are preferred for situations where a lot of sonic detail is desirable — like recording an acoustic guitar and capturing the sound of fingertips sliding across the strings. That same mic, though, set in front of a kick drum in live performance might deliver a muddy, unfocussed sound with too much ambiance and extraneous noise. For that situation, a mic of lower sensitivity which just picked up the thud of the drum might be a better choice.
In microphone specs, sensitivity is expressed in one of two ways — either as how strong a signal the mic generates, or how loud that signal is. For the first, the spec shows how many millivolts (1/1000th of a volt, abbreviated mV) it generates per Pascal (a unit of pressure measurement, abbreviated Pa). This spec will look something like this: 50mV/Pa. The higher this number, the more sensitive the mic.
The second version is actually calculated off the first. It's the ratio between that millivolt measurement and a reference level of one volt (V) and expressed in decibels (dB). This results in a negative number; our 50mV/Pa spec could also be written as -26dBV/Pa. If the spec is given in dBV, then the higher the negative number, the lower the mic's sensitivity.
A Shure USB condenser microphone
USB Microphones for recording direct to computer
Most microphone cables have either a quarter-inch jack or an XLR plug, which means you can’t plug them directly into a laptop. USB microphones, however, are ideal for simple home recording. All you need is the mic and your computer. Your computer’s USB port supplies power to the microphone. And the connection allows you to record directly to your computer’s audio editing software.
Wireless Microphones for video and performances
Wireless microphones come in a variety of sizes and configurations, but all offer the same basic benefit: freedom of movement. That can be helpful for a lead singer who can perform better roaming the stage. It’s also useful if you want to mic a saxophone — just attach a small wireless mic to the instrument’s horn. A wireless microphone uses battery power to transmit a signal to a receiver, which is connected to the mixing board the same way a wired microphone is.
A subset of microphones which are often used for wireless applications are lavalier mics. These are very small microphones with a wire running to a power pack/transmitter. Lavalier mics are used for video production. Reality shows and news programs often use lavalier mics, as the mic can be unobtrusively attached to a shirt collar, and the transmitter clipped to a the subject’s belt, out of camera view.
An AKG drum kit mic assortment
Starting from scratch? Consider a microphone bundle
Microphone bundles can save you a lot of trial and error as you gather gear for your home studio or live performances. Drum microphone bundles features a mix of dynamic and condenser mics. The dynamic mics are for the snare, toms and bass drum, and the condenser mics for the cymbals.
Some microphone bundles provide the accessories you need to get the best results with the mic. Such bundles may include things like a shock mount, pop filter, or mic stand.