Microphones

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Microphones

• The basics

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The microphone is your primary tool in the sound
chain from sound source to audio storage medium.
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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

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Types of Microphones

• There are three main types of microphones
• 1) Dynamic/Moving Coil
• 2) Ribbon
• 3) Condenser/Capacitor

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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

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Dynamic/Moving Coil microphonesAdvantages

• durable and can withstand a lot of volume before
  they distort (within their own circuitry).
• they dont 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.
• doesnt feedback as easily as other mics

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Dynamic/Moving Coil microphones 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.

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Dynamic/Moving Coil microphones disadvantage

• These microphones often miss the many subtle
  nuances of sounds because it takes a lot of sound
  pressure to move the coil.

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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

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Ribbon microphonesadvantages

• These microphones capture a warmer and smoother
  sound than dynamic/moving coil microphones.
• Dont feedback much in live situations.
• Dont require phantom power to operate.

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Ribbon microphonestypical 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.

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Ribbon microphonesdisadvantages

• colours the sound by adding a high frequency edge
  
• fragile
• will only pick up sounds that are very close.

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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.

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Condenser/Capacitor microphonesadvantages

• 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.

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Condenser/Capacitor microphonestypical uses

• recording studios
• can be used to record almost any soundexcept
  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.

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Condenser/Capacitor microphonesdisadvantages

• 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

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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

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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.

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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.

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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

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Conclusion

• Effective sound miking requires lots of
  experimentation.
• Most home studios should have at least one good
  moving coil and one good condenser mic.