Audio Lesson

1
Audio Lesson

• The Dynamics of Sound for Video Production

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Recording Audio

• Designed to add drama
• Designed to accurately recreate or express a
  desired listening experience.
• The sound engineer must create selective hearing,
  or try and select the sounds, the audience will
  hear and eliminate the sounds you dont want to
  hear.
• The mind can block out unwanted sounds

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Terminology

• Audio The Latin word for sound
• Pick up pattern The area a microphone can hear
• Frequencies The vibration rate that creates
  sounds
• Range (or Dynamic Range) the frequencies of
  sound the microphone can hear

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Terminology (Cont.)

• Amplitude The intensity of the sound. The
  relative loudness of the audio signal.
• Foley Art The technique of recreating sounds.
• Cardiod The shape of a microphone that
  resembles a heart shaped pick up pattern

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Terminology (Cont.)

• DAT Digital Audio Tape. This is a format that
  records sound onto an audio tape that records
  ones and zeros onto tape.
• HiFi High Fidelity recording. Often refers to
  the recording of differing signals for left and
  right audio channels.
• Mono The recording of a single audio track.

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Terminology (Cont.)

• Mic Level The signal is a low voltage signal.
  Less than .1 volts
• Line level The signal is a little higher
  voltage. Around 1 Volt
• Acoustics The ability of a material to reflect
  sound.
• Impedance the resistance of the microphone.

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Terminology (Cont.)

• Unidirectional pick up of sound from one
  direction
• Omnidirection The pick up of sound from all
  directions

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The Characteristics of Sound

• Sound is invisible but can be diagrammed by the
  ratio of voltage/time
• Wave is called a Sine wave
• 0

Amplitude
TIME
1 cycle or hertz
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Audio Signal Levels

• Low Level Microphone level. Very low voltage
  (signal) levels
• High Level the voltage output level of some
  microphones, audio mixers, VCRs, etc.
• PA Level Very high Amplitude output levels
  produced by Power Amplifier output. (Dangerous
  levels of electricity)
• Always disconnect the power to audio equipment
  when wiring!!!!

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Audio Sources

• Microphones
• Recorded sound devices
• Phonograph
• CD/DVD
• MP3 players
• Tape
• VCR/Cassette
• Cart Machines

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Types of Microphones

• Dynamic
• Ribbon
• Condenser

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Dynamic

• Dynamic microphone is like a tiny speaker
• Tends to be rugged
• Reliable and most used type
• Good for hand-held microphone use
• Used by singers in concert

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Ribbon Microphone

• Very sensitive to touch fragile
• Used in professional recording studios
• Can be hand held but not usually used as a live
  performing microphone
• Extremely expensive
• Extremely fragile
• Extremely sensitive

14
Condenser Microphone

• Requires a battery
• Wide range of quality and cost
• Used were size is a factor
• Can be made to fit a very small enclosures
• Can be used for recording, hand-held, lapel, and
  for portable recording

15
Classifications of Microphone Pick up Patterns

• Omnidirectional
• Unidirectional
• Cardiod
• Supercardiod
• Hypercardiod

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Omnidirectional

• The Microphone has a circular pick up pattern.
• Found on most lapel, stage, and general pickup
  microphones.

Pick up area
Microphone
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Cardiod

• Heart-shaped Pick up pattern
• Most common type

Microphone
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Super Cardiod

• Used for more directional pick up needs

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Hyper Cardiod

• Extremely directional.
• Often used on the side lines of a sporting event
  to hear the action on the field

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Sound Control

• An audio mixer combines audio sources
• Combines and adjust for different sound level
  inputs. I.e. A microphone level is lower than
  a CD input. The Gain for the Microphone must be
  adjusted higher than the CD level input.

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Summary

• Audio is just as important than video
• Audio has many different levels or voltages
• There are many types of microphones
• There are many types of pickup patterns used in
  audio
• Sound control is as important as mic selection.