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Microphones are characterized by
three things:
1. the type of element,
2. the pickup pattern, and
3. the physical form
Microphone Elements
There are three types of microphone elements. Crystal microphones
are used in telephones and shouldn't be used for sound reinforcement.
Dynamic microphones are the standard "abuse-taking"
microphones. Condenser microphones require an external source
of power such as a battery or phantom power from the mixer. They
are very sensitive to sound waves and are also very fragile. While
they cost more than a typical dynamic microphone, their sonic
quality is better and thus the price difference is justified.
Most lavalier and hanging microphones are condensers.
Pickup Patterns
For live sound, there are two main classifications of microphone
pickup patterns:
1. Omni
2. Cardioid
a. Cardioid
b. Super-Cardioid
c. Hyper-Cardioid
Omni-directional microphones "hear" or pickup sound
from all directions equally. Whether you speak into the front,
the side, or even the back, the microphone will pick up your voice
at the same volume. Omni-directional microphones are not ideal
for live sound reinforcement since they can pick up the amplified
sound and other noises in the room very easily and cause feedback
and other problems. They're most often found in lapel microphones.
A cardioid microphone blocks sound from the rear. If a child were
to hold a cardioid microphone upside-down, they would not be heard
too well. On the other hand, you wouldn't hear as much of the
rustling notes from the pulpit either (assuming the rear of the
mic is toward the pulpit or lectern).
A super-cardioid microphone has a tighter pickup pattern than
a regular cardioid microphone. It doesn't "hear" as
much sound from the sides.
A hyper-cardioid microphone is very specialized. A good example
is a shot-gun microphone. The microphone "hears" only
what it is pointing at--nothing from the sides and very little
from the back. If you use a hyper-cardioid microphone on a pulpit,
you wouldn't hear the person if they stepped to the side (and
didn't move the microphone).
The figures across the bottom of this page show how sensitive
each pickup pattern is at different angles from the top. Sound
from the front is considered to be at 0dB. Notice how sound is
about -6dB at the side of the cardioid microphone pattern--this
is half the sound pressure level compared to the front of the
mic!
Physical Form
Microphones come in many shapes and sizes depending on their intended
purpose.
The handheld microphone is the most common and most popular. It's
usually about 7 or 8 inches long and 2 inches in diameter at the
ball (head). It's held in the hand or used in a microphone stand.
Wired lavalier microphones (worn on a speaker's tie or lapel)
are small microphones the size of your thumb or smaller. They're
not too popular simply because the speaker must fight the cable
dangling from his or her leg. Some people love them, others prefer
the wireless version.
Hanging microphones are usually small and are hung from their
own cable. They're used to mic choirs, orchestras, or to just
pick up the ambient sound in the room (to add life to a recording).
Pulpit microphones are mounted on a pulpit or lectern. They have
a very small microphone element on the end of a flexible gooseneck
arm. This is a nice way to provide a hands-free microphone for
anyone to use. Unfortunately, mounting usually requires that a
number of holes be drilled in the pulpit. This can especially
be a problem when the pulpit or lectern is small and is used for
other events in different locations where the microphone can get
in the way.
Of the two main wireless microphone styles, the wireless lavalier
is by far the most widely used. It allows unlimited freedom of
movement by the user. Nothing to hold, nothing to get tangled
up in. A wireless lavalier microphone is best suited for speech,
not music or singing.
Wireless handheld microphones are great when several people in
a group need a microphone at different times. They simply pass
it person-to-person. There are no wires to tangle up or trip on.
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