Digital Sound & Music: Concepts, Applications, & Science, Chapter 1, last updated 6/25/2013
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Figure 1.9 A dedicated 48-channel multitrack recorder
1.5.2.6 Microphones
Your computer may have come with a microphone suitable for gaming, voice recognition, or
audio/video conferencing. However, that‟s not a suitable recording microphone. You need
something that gives better quality and a wider frequency response. The audio interfaces we
recommend in Section 1.5.2.2 include professional microphone inputs, and you need a
professional microphone that's compatible with these inputs. Let's look at the basic types of
microphones that you have to choose from.
The technology used inside a microphone has an impact on the quality of the sound it can
capture. One common microphone technology uses a coil that moves inside a magnet, which
happens to also be the reverse of how a loudspeaker works. These are called dynamic
microphones. The coil is attached to a diaphragm that responds to the changing air pressure of a
sound wave, and as the coil moves inside the magnet, an alternating current is generated on the
microphone cable that is an electrical representation of the sound. Dynamic microphones are
very durable and can be used reliably in any situation since they are passive devices (A passive
device is one that requires no external power source.) Most dynamic microphones tend to come
in a handheld size and are fairly inexpensive. In addition to being durable, they're not as sensitive
as other types of microphones. This lower sensitivity can be very effective in noisy
environments when you're trying to capture isolated sounds. However, dynamic microphones
may not pick up transient sounds as well quick loud bursts like drum hits. They also may not
pick up high frequencies as well as capacitance microphones do, which may compromise the
clarity of certain kinds of sounds you‟ll want to record. In general, a dynamic microphone may
come in handy during a high-energy live performance situation, yet it may not provide the same
quality and fidelity as other types of microphones when used in a quiet, controlled recording
environment.
Another type of microphone is a capacitance or condenser microphone. This type of
microphone uses an electronic component called a capacitor as the transducer. The capacitor is
made of two parallel conductive plates, physically separated by an air space. One of the plates
requires a polarizing electrical charge, so condenser microphones require an external power
supply. This is typically from a 48-volt DC power source called phantom power, but can
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