Microphone Placement

by Mark Tomlonson
Published on Jun 22, 2001 12:00 AM



Both condenser and dynamic mics come in small diaphram and large diaphram types. A small diaphram is about 1/2 inch in diameter, but can be even smaller. A large diaphram is about an inch in diameter. The main difference between the two is in how they pick up the very lowest sounds - below what the human voice can produce. For video work, small diaphram mics are generally preferred for anything on-camera. Large diaphram mics are used for music and other applications where the lowest frequencies need to be captured.

When holding a microphone in hand, any movement will be picked up by the microphone. There are microphones that suspend the microphone inside the case on rubber mounts to isolate the mic from hand noise. These are very popular in local television broadcast work, where the on-camera reporter must use one mic for himself as well as the interview subject, moving the mic back and forth between the two. The most popular microphone of this type is the Electro-Voice RE-50, which you have seen used by television reporters many times whether you knew it or not. Another one is the BeyerDynamic M58. It's slightly longer and thinner than the EV, and is finding wider use because it allows less clutter around a subject's face.

When a microphone is used outdoors, it will pick up wind noise. Sometimes better than the sound you're trying to pick up. To cut down on wind noise, a foam sock is put over the mic. It's important to use a windscreen designed for the microphone you're using. At close quarters, less than a quarter of an inch, anything near a microphone will affect not only the pick-up pattern, but can cause shifts in the tone. The microphone manufacturer will take this into account when designing the windscreen, and will work long hours to design a screen that effects the sound as little as possible. Not all of them are made out of foam. One popular type of shotgun mic uses a windscreen made out of fake fur, in the shape of a sausage. The German manufacturer, though, prefers to call it a "Zeppelin". Popular in movie and national television reporting, you've also seen this type of microphone many times. There's no magic to how a windscreen works - it cuts down on the high frequencies. Because of this, windscreens shoudl only be used when needed. But keep them handy - you'll need them soon.