Why the Microphone Your Agency Uses Matters (Part 1)
Need a voiceover for a 30-second animation? How about a field recording during a live-action video shoot? Whatever your video project, if you need audio, you need a skilled audio engineer who knows his or her way around microphones and microphone accessories. In this two-part series, you’ll learn all about microphones, what mic equipment you may see at an audio recording or video shoot—and why the right mic can make or break your project.
A great marketing video can seem effortless in its production. The words, images, music and sound blend together seamlessly to tell a great story that engages your customers. But the reality is quite different. Behind every video is a team of experts, each highly skilled in the software, hardware and artistry that makes for a great final product.
One of these team members is your audio engineer, and it’s essential that they know their way around microphones.
Selecting the best microphone is vital to producing audio that makes your video stand out. Think of a good microphone as the gateway to a high-quality audio recording. If the sound isn’t accurately captured at its source, the consequences can be difficult or impossible to compensate for.
Every recording session presents its own unique set of challenges. An audio engineer’s primary task is to define the creative goals. What kind of sound do you want to capture? (The human voice? The ambience of interior settings? Outdoor nature sounds? Musical instruments? Foley sound effects?) And, how will that sound contribute to the final production?
Once your audio engineer knows what you want and why you want it, they can decide how best to record it.
Kinds of Mics
Microphones are limited in scope and task. No single mic has yet been developed that can record every kind of sound with equally excellent results. So a good recording engineer needs to be familiar with a wide variety of equipment.
There are several kinds of microphones commonly found in a well-appointed recording studio, but two types are most common: dynamic and condenser. Each class has advantages and disadvantages.
These mics are commonly used in live music settings where the sound source has a relatively high volume level. Dynamic mics, also called moving coil mics, are known for their durability, which makes them a road-worthy travel mic. In recording studios, it’s often the first choice to closely mic instruments that produce low to mid-range sounds with a lot of volume, such as drums and guitar amps. They require no external power source.
Most condenser microphones have a higher sensitivity to volume and capture a flatter frequency response than dynamic mics. The best (and most expensive) studio vocal mics are usually a condenser type. They are not commonly used for live sound reproduction because they are usually more expensive and less rugged than dynamic mics. However, condenser mics are preferred in live music settings for overhead drum miking because cymbal sounds occupy a higher frequency range with less volume than drums.
Condenser mics require an external power source to convert acoustic energy to electrical energy. This is accomplished with batteries installed in the mic itself or by the use of “phantom power” supplied through the microphone’s cable from the mixing unit or preamplifier.
Pickup Pattern—the Science of Sound
The pickup pattern is another very important consideration when choosing the right microphone for a specific task. The pickup pattern determines the directional way in which a microphone hears sound. In general, there are three kinds of pickup patterns associated with microphones: omnidirectional; bidirectional and unidirectional.
These mics pick up sounds from all directions – basically, in a spherical radius surrounding the mic. Omnidirectional mics are appropriate for some general recording needs, but they lack the focus required for a clean audio mix. When sound comes from all directions, it is very difficult to precisely isolate a featured sound. This is a good effect, however, for recording crowd noise or when the desired effect is to create confusion.
Bidirectional mics pick up sounds from two locations simultaneously, usually front and back. These mics are not in common use these days. They were originally designed to record interviews for TV and radio programs, when a guest would sit at a table directly across from the host. Nowadays, two unidirectional mics can be used to achieve that effect with much greater individual control from voice to voice.
Today, unidirectional mics are by far the most prolific design. A unidirectional mic can be “aimed” at the sound source for a nicely isolated recording with minimal background interference.
Tune in next week for Part 2 in our microphone series as we answer your burning questions about the mics and audio equipment you’ll see on live video shoot.