Microphones
§The basics
§The
microphone is your primary
tool in the sound
chain from sound
source to audio storage medium.
tool in the sound
chain from sound
source to audio storage medium.
§Factors when capturing a sound
with a microphone:
§
§microphones location in relation
to the sound source
§
§the acoustic environment in which
we choose to record the sound source
§Types of Microphones
§There are three
main types of microphones:
§
§1) Dynamic/Moving Coil
§2) Ribbon
§3) Condenser/Capacitor
§1) Dynamic/Moving Coil
microphones
§Example: Shure SM 57
§
§
§They operate on a magnetic
principle : movement of a copper coil around a magnet causes a changing flow of
electrons that represent the sound wave
§
§Dynamic/Moving Coil
microphones
Advantages:
Advantages:
§durable and can withstand a lot
of volume before they distort (within their own circuitry).
§
§they don’t require phantom power to
operate.
§
§colours the sound in range between
5-10khz, this adds clarity, presence and understandability to many vocal and
instrument sounds.
§
§ doesn’t feedback as easily as other mics
§
§Dynamic/Moving Coil microphones
typical uses:
typical uses:
§mostly live situations, but they
are also used a lot in the studio.
§
§close mic applications (1-12 inches)
§
§snare drums, guitar amplifiers,
kick drum, vocals and any instrument that can play loud.
§
§
§
§Dynamic/Moving Coil microphones
disadvantage:
disadvantage:
These microphones often miss the many subtle
nuances of sounds because it takes a lot of sound pressure to move the coil.
§2) Ribbon microphones
§Example: Beyer M 160
§
§a metallic ribbon is suspended
between two poles of a magnet. Sound waves vibrate the metallic ribbon which
causes a varying flow of electrons to the different poles of the magnet
§
§Ribbon
microphones
advantages:
advantages:
§These microphones capture a
warmer and smoother sound than dynamic/moving coil microphones.
§
§Don’t feedback much in live
situations.
§
§Don’t require phantom power to
operate.
§Ribbon microphones
typical uses:
typical uses:
§Typically used in the studio
because they are fragile
§
§Used in close mic applications
(1-12 inches)
§
§Often used for acoustic guitars.
Also work well for vocals.
§
§Ribbon
microphones
disadvantages:
disadvantages:
§colours the sound by adding a
high frequency edge
§
§fragile
§
§will only pick up sounds that are
very close.
§3) Condenser/Capacitor
microphones
§Example: Audio Technica AT 4033
§
§How
do condenser microphones work?
§ A charged electrical current is
applied to a metal-coated piece of plastic. the coating vibrates
sympathetically in response to a sound wave because it is very thin.
§The metal-coated piece of plastic
is positioned close to a piece of metallic alloy.
§The changes in the space between
the surfaces create a changing discharge of electrical current.
§It makes an electrical version of
acoustic energy from the sound source.
§
§Condenser/Capacitor
microphones
advantages:
advantages:
§they respond to fast attacks and
transients more precisely than other mics and add little tonal colouration
§
§they can be used to record sounds
from a greater distance and capture a broader range of frequencies
§
§ big advantage: these mics record
a sound while capturing natural ambience of a room.
§Condenser/Capacitor
microphones
typical uses:
typical uses:
§recording studios
§
§can be used to record almost any
sound…except very loud ones (ex. Kick drum)
§
§ extremely effective with quiet
sounds
§
§the perfect choice for capturing
room ambience.
§
§almost always used for vocals ,
acoustic guitars and drum ovreheads.
§
§Condenser/Capacitor
microphones
disadvantages:
disadvantages:
§fairly fragile
§
§feedback too easily in a live
environment (although some have low frequency roll off switches to help
alleviate feedback frequencies)
§
§require phantom power to operate
§
§
§Microphone polar patterns:
§A polar pattern is the pickup
pattern of the microphone.
§
§There are three
main
types of patterns:
§
§1) Cardiod
§2) Bi-directional
§3) Omnidirectional
§
§
§
§Frequency Response
§Most microphones respond to
frequencies within and beyond the human range of hearing.
§
§Our ears have the ability to hear
frequencies from 20-20 000 hertz .
§
§All microphone manufacturers
provide specifications for the frequency range of their products.
§Frequency response curve
§The
frequency response curve
of a microphone shows how the microphone responds to different frequencies
across the audible spectrum.
§
§A mic with a flat response adds
little colouration to the sound. Many mics drop off sharply in the frequencies
below 300 hz. Yet boast frequencies in the area of 4000 hz.
§
§Pre-amplifiers
§Although a microphone can be
plugged directly into a mixing board, better results are often achieved by
using a pre-amplifier.
§
§Example: Universal Audio 2-610
§Conclusion
§Effective sound miking requires lots of
experimentation.
§Most home studios should have at
least one good moving coil and one good condenser mic.
§
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