Microphones Are Cool, part 2
Last issue we started our look at microphones. This issue we will discuss some additional microphone characteristics.
Pickup Pattern
A polar pattern is a graphic representation of the directional characteristics of a microphone. The most common polar patterns are shown below.
Why do so many pickup patterns exist? Each pattern provides a unique solution to a specific set of problems in a given application. An omnidirectional mic hears sounds from all around it. A unidirectional mic hears sounds from one specific location. A bi-directional mic actually hears sounds from two specific directions - directly in front of it, and directly behind it. And a hemispherical mic hears sounds above a certain plane.
Proximity Effect
Proximity effect is a characteristic of directional microphones resulting in an increase in the response at low frequencies when the mic is used at a close working distance. To illustrate this point, try another experiment - this time comparing the sound of a cardioid mic with an omni mic. Speak into each one from about two feet away and adjust the volume of each so they sound equal. Now, shut off the cardioid mic. Face the omni mic, start speaking and slowly move the mic closer to your mouth. Notice that the volume increases as you get closer to the mic, but that there is no change in the character of the sound. Now try the same experiment with the cardioid mic. Note that as you get closer to the cardioid mic, not only does the volume increase, but your voice sounds fuller and warmer. That's because the low frequencies of your voice get boosted more than higher frequencies, almost as though someone had turned up the low frequency EQ control on the console.
Many singers and speakers like this effect because it makes their voice sound bigger. Proximity effect can also work as a disadvantage by making the overall sound too thick. Simply be aware that anytime you use a directional mic, its proximity effect should be taken into account.
Handling Noise
This is one characteristic that can immediately ruin your day if it's working against you. When you pick up a mic, toss it around in your hand, or even place it on a mic stand, you don't want to hear any extraneous sounds. If you tug or tap on the mic cable, and hear that sound through your sound system, you have a mic with poor handling noise.
Effective, integral shock mounting is one thing that sets apart the construction of cheap mics from the construction of high quality mics.
Summary
A microphone is one of the most important tools that a sound technician has. His/her choice of which of these tools to use in a given situation will have a major bearing on the end result - the sound that is captured on tape or that the congregation hears over the sound system. The variety of mics available on the market seems overwhelming, yet each one provides a unique solution to a given problem. As one audio scholar once put it, the availability of a certain piece of equipment is inversely proportional to its need.
Learn all you can about these tools. Experiment!!! Purchase the best quality mics that you can afford, but never overlook that cheap old mic that someone threw in the drawer. Someday, it may just turn out to be the perfect mic for the job.
Curt Taipale
Curt@K2Audio.com
http://www.ChurchSoundcheck.com
