Specifications

12
TRANSDUCER TYPE
As mentioned earlier, microphones serve just one purpose: to convert
sound waves into electrical energy. The part of the mic that actually does the
conversion is called the transducer
or cartridge. But different types of
transducers perform the conversion in different ways, and each type of
transducer has certain characteristics that make it more or less suitable for
various applications. For the most part, two types of transducers are used
in microphones for broadcast and audio-visual productions: the dynamic
and the condenser.
Dynamic
microphones (also called moving coil microphones) use a
simple magnet and coil of wire to convert sound waves into an electrical
signal. Here’s how it works: a thin diaphragm with a coil of fine wire
attached vibrates in response to sound waves. This causes the coil of wire
to move back and forth around a magnet, creating a small amount of
electricity, which flows through the microphone cable.
Good quality dynamic mics offer very good sound quality, are very
rugged, and will usually tolerate rough handling or exposure to extreme
temperatures and humidity. For these reasons, dynamic microphones have
traditionally been the most popular for most professional applications.
Condenser
microphones (also called capacitor or electret condenser
microphones) use an ultra-thin piece of plastic or metal stretched tight just
above a piece of flat metal or metal-coated ceramic, called a backplate.
When a fixed electrical charge is placed on the diaphragm/backplate
assembly, its electrical output varies depending on the movements of the
diaphragm, which vibrates in response to sound waves. This output signal
is extremely weak and subject to outside electrical interference, however, so
it must be modified and/or amplified by a circuit called a preamplifier
. The
preamplifier can either be located in the handle of the microphone or in a
small outboard electronic pack.
Cutaway view of dynamic (left) and condenser microphone cartridges