Sure, a built-in microphone is fine if you just want to get sound. But if you want to record audio, an external microphone is a must. Splitting hairs? Not really.
Audio is transparent. Sound is noisy. Audio is purposeful. Sound just happens. Audio is “laid down.” Sound is “captured.” Audio creates a mood. Sound just makes people moody.
And here’s the best part: it doesn’t take a huge investment of time or money to improve your video with better audio. But before you get a gun permit for a super-duper-hyper-cardioid shotgun, read on to find out what type will best fit your shooting style.
Lookingfor Mr. Microphone
Using an external microphone will usually get you better audio; but using the wrong type could make things worse. To get familiar with what’s out there, here is a look at the various types and uses.
Sometimes used by aggressive reporters as a cudgel, the handheld microphone is truly a workhorse. They are good for interviews where someone either on or off camera is able to keep the distance to the subject about the same. The solo handheld often takes center stage when placed on a U.S. Senate chamber table for several sacrificial lambs to paw at while being grilled.
What used to look like a Cuban cigar lashed to a TV host’s neck is now a fruit fly on Connie Chung’s lapel. The lavaliere has become a standard piece of gear for anyone wanting good audio without the hassle of constantly adjusting microphone position. They clip on to a lapel or tie, and often even hidden behind clothing. Hard-wired versions reduce the chance for interference but wireless configurations are common.
The shotgun often appears on top of a camera to get that “up close” audio without really being all that close. These microphones are extremely directional, so take extra care to point it accurately at your subject. Many sports and news videographers use it to record the grunts and groans at games and city council meetings. It is also a good choice for shooting wildlife, but don’t expect any miracles at distances of 100 meters. With this shotgun, you won’t need a hunting license either.
Designed primarily for use in recording studios, they offer the highest quality audio. They may be worth investigating if you need pristine audio but beware, these are expensive and require special adapters for use with a camcorder.
PZM or Boundary
These are excellent for recording a group of people sitting around a table. Frequently used for teleconferencing, they are great for recording meetings and can be good for speakers at podiums.
A Microphone with a Heart
After you have decided on a microphone type, you’ll need to consider the pickup pattern. While some allow you to select between various patterns, most microphones are more sensitive to sound coming from a specific direction and distance.
The most common is the cardioid pattern, so named because of its heart shape. This is a good general-purpose pattern that records a single subject while rejecting most other sounds. Most hand held and many lavaliere microphones use this pattern.
An Omni-directional pattern is less discriminating. It picks up sound equally well from nearly all directions. This is a good choice if you can only place a microphone on one person and still need to hear subjects nearby.
Bi-directional patterns are great if you have two subjects on either side of the microphone, such as with a singing duo.
Super and hyper-cardioid patterns are the most directional of the bunch. You will find these used exclusively on shotgun microphones. While these are excellent at rejecting most sound not directly in front of the element, even the best will not sound as good as a lesser quality condenser microphone up close.
And He’s so Sensitive
Not only are there several different microphone types, but the method in which they convert sound waves into an electric signal also varies. Some have elements that are more sensitive than others. Let’s look at the most common.
Dynamic. This is the simplest and most durable of the microphone elements. It works like a speaker in reverse. Sound waves drive the diaphragm, which in turn moves a coil in a magnetic field and presto: an electric signal is born. These tend to generate the weakest signal and their frequency response is not as good as others, but if you want dependable, this is it.
Condenser and electret-condenser. Most modern microphones use some form of condenser. Unlike the dynamic microphone, this one needs a power supply, usually from a battery or, in more expensive models, directly through the microphone cable. Audio mixers and some other pro-level audio equipment have a “phantom power” feature that is compatible with these microphones. Many use balanced cables, feature very low noise circuitry, are available at reasonable cost and have an excellent flat frequency response.
Ribbon. High-quality studio microphones often use a thin metal ribbon to generate a signal. They sound great, but are delicate and therefore limited to studio work only. Drop one and you’ll need to sell your Hyundai to get another.
Great Video with a Microphone
With all this focus on selecting the right microphone with the right pick-up pattern and element, don’t forget that the best way to ensure any microphone will sound its best is to always use headphones to monitor your audio. Combine this habit with using your thoughtfully selected external microphone and you’ll be getting the best compliment anyone focusing on audio can get: “Great video!”
Brian Peterson is a Communications Director with the American Lung Association and has more than 14 years of broadcast video production experience.
Sidebar: Cutting the Cord
A good wireless microphone is practically a must for recording weddings and special events where your subjects are at a distance. Of course, the big advantage is: no cords! Disadvantages include always having to have fresh batteries either installed or at the ready or, better still, installed and another set at the ready. Some cheap and older models have problems with dropout and interference from surrounding radio frequencies. However, many newer designs incorporate “true diversity” that will keep the UPS man from cutting in between the “I do”s.
Better models allow you to select from several frequencies if you find a problem on a particular channel. Be sure to consider how far away from your subjects you will be and get one with enough range.