| Keep it Simple | Better Sound: About Microphones | Wired Microphones | Wireless Microphones |
KISS -- Keep It Splendidly Simple -- is the rule here. With audio, it seems Murphy's law applies with a vengeance. Anything that can go wrong probably will. The more microphones, wires and connectors that are used, the more buzz, hum and equipment failure is likely to occur.
Consequently, many non-professionals find that the microphone on their camera provides audio that is entirely adequate. Mostly they are interested in recording the voices of their subjects, along with ambient sounds -- the babble of a stream, the roar of the crowd at a football game, the sound of wind in the trees.
Sometimes, however, you may want to record a speaker without much ambient sound, or record speakers who are simply too far away for the camera to pick up what is being said. To do this you must turn to an external microphone, either wired or wireless.
As always, buy the best equipment your budget will allow. Companies such as Azden and Shure carry an extensive line of good quality audio tools. Many local stores carry these products. Music stores that cater to professional musicians are usually good sources of audio equipment, and are apt to have very knowledgeable staff on hand to help you.
We've had good experiences with some Radio Shack equipment, especially lavaliere and PZM microphones, which are made by a major audio equipment manufacturer for resale under the Radio Shack logo. They make a very nice four-microphone mixer, too.
Audio equipment can be purchased by mail order. When purchasing via mail order, be sure to inquire about hidden costs, such as shipping and handling. Some unscrupulous companies will tack on as much as 8 to 10 per cent of the purchase cost for "handling." Be sure to get the name of the salesperson who takes your order, too.
Better Sound: Using a Microphone with Your Camera
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Your camera has a build-in microphone, capable of doing a pretty good job of picking up sounds from a few feet away. But as the distance between you and the sound source increases, the quality and volume of sound decreases rapidly.
Logic would suggest that if the sound source -- the speaker you are video taping -- at #1 is moved to position #2, the level of sound reaching the microphone would be halved, since it is now twice as far from the microphone as it was. In fact, because of what is known as the inverse square law (which you can find spelled out in great detail at this web site by looking for the topic "Inverse Square Law" in the index in the frame on the right side of the page) the sound level is quartered. It's not just a little weaker, it's a lot weaker. |
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The Problem
Not a week goes by here at VideOccasions without someone asking us to "do something about the sound" on their video tape. Usually there's lots of hum, the volume is very low and there's quite a bit of background noise.
The Causes
The Solution -- Use an external microphone. Many newer video cameras -- some older ones, too -- have a "mic in" port, a receptacle into which a microphone plug can be inserted. An external microphone -- a "mic" -- can be purchased for as little as $25 from Radio Shack. With an extension cable, a microphone can be placed as far as 30-40 feet from the camera and still be only a few inches from the sound source.
Lavaliere (tie-clip) mics are excellent to use when taping interviews and speakers. They are small and unobtrusive, yet yield very good sound.
The placement of lavaliere mics is very important. Remember the "inverse square rule:" every inch the speaker turns away from microphone reduces volume by the square of the distance. Four inches away reduces the volume by a factor of 16.
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The white dots on the illustrations indicate the best location for a tie tack (lavaliere) microphone. |  |
Judy and I, chatting on camera at the ball game, look at each other as we speak. The microphone placement assures maximum coverage. We could probably get by with a single microphone, but we'd be assured of better sound if we each had one.
For multiple microphones, a "mic mixer" is used: it enables the sound from multiple microphones to be combined and passed onto the camera as a single signal. Low cost but very effective mic mixers can be purchased at many consumer electronics stores.
And a final suggestion: If your camera has a receptacle for a headphone plug, get a headphone. That way you'll be able to hear what the camera hears. It can make the difference between a mess and audio that sounds great!
For more information about microphones, take a look at the Queen's University Department of Film Studies, Kingston, Canada microphone page.
A disadvantage of the wired microphone is that camera and speaker are attached. Where ever one goes the other must follow. Wired microphones works well for a stationary speaker, but is not very effective for the speaker on the go.
Also, if the cable is more than 10 to 15 feet in length, someone must act as a "cable puller" and make certain the cable isn't getting wrapped around the furniture if the speaker and camera operator do move.
One way around this, of course, is to have the microphone fixed on a stand, with the speakers approaching the microphone. This works well when speakers are at a podium, for example.
Be sure to use shielded audio cables for your microphones. This will cut down considerably on outside interference. And if possible, use a headset to listen to the sound coming in from your external microphone. Any interference you hear will be recorded by your camera.
Wireless microphones may be hand held or on a stand, but are much more commonly of the lavaliere or pin-on type. There are even professional specialty wireless microphones, designed for use on stage or in film and video, that can be worn on a headband or hat, or hidden in the hair.
The advantages of the wireless microphone are obvious. The wearer and the camera operator have complete freedom of movement, although they must stay within 150 to 300 feet of each other for optimum reception.
The major drawbacks to wireless microphones are cost and the possibility of interference . Wireless systems start at about $250 to $300, with the top of the line being well in excess of $1000. Low cost wireless microphones can be obtained for considerably less than this, but usually are of poor audio quality.
If you decide to purchase an inexpensive microphone, either wired or wireless, make certain that the store where you make your purchase has a return policy. Write down the name of the sales clerk who waited on you, and be sure to keep the receipt.
Interference has always been a major problem with wireless microphones. Increasingly, good quality systems are designed to transmit in the UHF rather than VHF frequencies, to provide interference free transmission. Top of the line systems have multiple frequencies from which to choose.
If you must use a wireless microphone system, and can afford better quality, buy what's called a "true diversity" receiver. Receivers of this type automatically seek out an interference free frequency, unlike other microphone/receiver combinations which must be switched from one channel to another manually at both the microphone and receiver.
If there is one axiom to follow in the realm of audio it is this: always buy the best equipment you can afford.
Last modified 2/17/08