Microphone Overview: Condenser Type
The condenser microphone is, without a doubt, the most popular style of microphone used in recording studios (home or commercial). Condenser mics are sensitive and accurate, but they can also be expensive. Recently, however, condenser mics have come down in cost, and you can buy a decent one for about $200. Very good ones start at about $500.
The condenser microphone has an extremely thin metal (or metal-coated plastic or Mylar) diaphragm (the part that senses the signal). The diaphragm is suspended in front of a metal plate (called a backplate). Polarizing voltage is applied to both the diaphragm and the backplate, creating a static charge in the space between them. When the diaphragm picks up a sound, it vibrates into the field between it and the backplate. This produces a small signal that can then be amplified. The following illustration shows how a condenser mic is constructed.
Condenser mics need a small amount of voltage (from 9 to 48 volts) to function. If you use a condenser mic, make sure that either it has its own internal battery or you have a preamp or mixer equipped with phantom power, which is a small amount of voltage that is applied to a condenser microphone when it’s connected.
Here are a few additional decisions you need to make when selecting a condenser mic:
Tube or solid-state? Condenser mics can be made with either vacuum tubes or transistors (known as solid-state). As with all the tube or solid-state gear, base your decision on the sound characteristics that you prefer. For the most part, tube condenser mics have a softer high end and a warmer overall tone. Solid-state mics, on the other hand, are often more transparent — they capture the sound with less coloration.
Large- or small-diaphragm? Condenser mics come in two broad categories: large-diaphragm and small-diaphragm. Large-diaphragm mics are more popular than their smaller-diaphragm counterparts, partly because large-diaphragm condenser mics have a more pronounced bottom end (low frequencies). Large-diaphragm mics also possess a lower self noise — that is, noise created by the microphone.
Before you buy only large-diaphragm mics, consider this: Small-diaphragm condenser mics often have an even frequency response and can more accurately capture instruments with a pronounced high-frequency component (violins, for instance).Condenser mics can have either large or small diaphragms.