Surface Mount: These microphones are designed to work on a flat surface. They are usually physically contoured to look less intrusive on a conference table or desktop.
The microphone element is located very close to (but not touching) the surface, so that sound waves reflected from the surface arrive at the mic element at the same time as the direct sound.
This effectively doubles the sensitivity of the microphone compared to a free-standing handheld type at the same distance. (This sensitivity boost assumes that the surface is sufficiently large to reflect even low-frequency sound waves.)
Tips on Using Surface Mount Mics: Surface mount microphones work best when positioned on a smooth, flat surface, such as a table or desk.
If table vibrations are a problem, try putting a very thin piece of soft foam rubber underneath the mic. (A computer mouse pad with a hard top surface often works well.) In some situations, surface mount mics can even work well when mounted on a wall.
Keep in mind that the sound quality of this type of microphone is affected by the size of the surface on which it is placed. For best results, use a surface at least 3 feet square; using a smaller surface will tend to reduce pickup of low frequencies.
The effect on speech frequencies is usually mild, and may actually improve intelligibility of very low voices by reducing boominess.
Shotgun: The shotgun microphone is so named because the long, slotted tube in front of the microphone cartridge makes it resemble a shotgun.
This “interference tube” helps reject sounds coming from more than about 30 degrees off to the sides, while still picking up sounds from the front.
This extremely directional pickup pattern (called a line/gradient pattern) makes shotgun mics popular for TV news and movie sets.
Shotgun microphones are not telephoto lenses for sound. They do not allow you to zoom in on a conversation from 100 feet away. Here’s a much more accurate analogy: imagine looking through a long tube at a person standing 20 feet away.
The person’s image does not appear to be any larger or closer, but is somewhat easier to see, because the eye is not distracted by things happening off to either side. This is exactly what shotgun mics do best – screen out sounds coming from the sides.
In practice, a shotgun microphone can typically be placed at four to five times the acceptable distance for a standard omnidirectional microphone. Keep in mind that the shotgun mic will also pick up sounds coming from behind the subject.
Tips on Using Shotgun Mics: Shotgun mics can be positioned either slightly above, below, or to the side of the sound source, so that the mic does not appear in the camera frame. Try to avoid aiming the mic at a hard surface, such as a tile floor, brick wall, or hard ceiling.
These surfaces reflect sound waves, and may reflect background noise into the microphone or cause the sound to be slightly hollow. A heavy blanket can be placed on a reflective surface to provide some temporary sound absorption.
Shotgun mics are more sensitive to wind noise than standard microphones, so try to avoid moving the mic rapidly and use a foam windscreen if possible. Larger “zeppelin” or “blimp” type windscreens are usually necessary outdoors. Also, it’s a good idea to use a rubber-isolated shock mount to control handling noise that may be transmitted through a stand or boom.
Hopefully, no matter your skill level, you’ve found some new information that will be useful when the next time you find yourself working with video. Remember, when it comes to microphones, the number one goal is clean audio, but a little bit of experimentation never hurt anyone.
Supplied by Shure Incorporated. For more information visit Shure.com.