Audio Video Production Audio Basics 1 Copyright Texas Education Agency 2012 All rights reserved Images and other multimedia content used with permission Sound Sound has two basic characteristics ID: 658732
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Copyright © Texas Education Agency, 2012. All rights reserved. Images and other multimedia content used with permission.
Audio Video
Production
Audio Basics
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Copyright © Texas Education Agency, 2012. All rights reserved. Images and other multimedia content used with permission.
Sound
Sound has two basic characteristics:Loudness - measured in decibelsFrequency - measured in Hertz
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Loudness
dBSPL (sound pressure loudness)
Measure of acoustic power
Sounds we can hear with our ears135 dB is considered “threshold of pain”
Ears ringPoint at which hearing damage can occur
Sound
dBs
Jet
140-150
Rock Concert/ Gunshot
135-140
Jackhammer
85-90
City Street/ Restaurant
70-75
Quiet Conversation60-80Office Environment45Whisper30“Silent” studio20
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Loudness
dBm Unit of electrical power
Measured with VU metersDigital VU meterAnalog VU meter
In live production, “0” is considered the maximum desirable sound level0 is also called “Unity”In post-production, the audio levels are between -12 and -6
dB.“0” should NOT to be reached
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Education Agency, 2012. All rights reserved.
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Frequency
Basic pitch of sound (how high/low it is)Audible (hearing) range: 20Hz - 20,000Hz20Hz - extremely low pitch, rumble
20,000Hz - extremely high pitch, higher than highest note of a violinCommon hearing range: 50Hz - 15,000Hz
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Acoustics
Most sound booths incorporate different types of soundproofing materialsHard walls; tile floors will allow too much reverberation
Reverb - sound remaining after the original sound stops Too much soundproofing causes a dead, lifeless sound
Ideal room for recording and listening has free-standing, sound-absorbing items (furniture, rugs) 6Slide7
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Types of mics
Dynamic microphone
Uses a small coil that moves
within a magnetic field when activated by sound
Pros:Rugged and durable
Can withstand weather
a
nd
rough handling
Great for ENG (electro
nic
news gathering)
Low Cost
No power necessaryCons:Larger and heavierNot the best choice for quality audio7Slide8
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hts
reserved. Images and other multimedia content used with pe
rmission.Types of mics
Condenser microphone
Has a plate that moves against another plate to produce a signal
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Pros:
More sensitive
Better quality
Can be small
Cons:
Fragile and sensitive to shock and temperatures
Needs power
Battery
Phantom power supplied by camera or audio mixer
ExpensiveSlide9
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Types
of micsRibbon microphone
Uses a small ribbon (rather than coil) moving in a magnetic fieldSimilar to condenser mics in pickup quality and sensitivityProduce warm, rich sound
Very sensitive to rough handling and moving airRarely used outside an audio booth
9
LuckyLouie.
RCA 44 Ribbon Microphone.
4 November 2007
.
<http://en.wikipedia.org/wiki/File:Rca44.png>.Slide10
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How microphones “hear”
Microphone Pickup Patterns
OmnidirectionalPicks up sound in all directionsUnidirectional (cardioid)
Focused hearing in one directionCardioid - “heart-shaped” pickup patternHypercardioid - narrow pickup pattern with a “long reach” (for distances)
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Omnidirectional
Unidirectional
CardiodSlide11
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reserved. Images and
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How mics are used
Handheld micLavalier (lapel) micBoom (shotgun) micDesktop mic
Headset mic
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Handheld Microphone
Held by the talentAllows for talent to control
mic’s locationReporter can easily move it closer to interview
Singer can control intimacy of the sound by holding it closerField reporters - need dynamic handheld (rugged, durable)
Singers - need condenser handheld (better sound quality)DisadvantagesCan be distracting (takes up visual space)
Talent’s hands are not free
Quality of sound depends on proper placement by talent
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Lavalier Microphone
Small, rugged, omnidirectional
Usually clipped to shirts six to
eight inches below talent’s chinAdvantages
Talent can move freelyMic never moves
Sound is consistent
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Disadvantages
Each on-camera subject requires
mic
Requires proper setup and placement
Clothing may rub
mic
or muffle soundSlide14
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Lavalier Microphone
“Dressing” lapel mics (hiding wires)
Under clothing
Have talent run microphone under the shirtClip mic to tie, lapel, collar or button flap
Careful of material rubbing mic or obstructing soundOutside clothingRun mic up the back of talent (outside clothing) and over the talent’s shoulder near the collar (under collar if possible)
Clip mic to lapel, collar, or button flap
Use gaffers tape (on talent’s back) to keep the mic cable from moving
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Boom Microphone
Unidirectional mics intended to pick up sound without being seen on camera
“Shotgun” microphone mounted to the end of a telescoping boom polePole has shock-mount to absorb all movementCan be held above talent or at low angle below
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Desktop Microphone
Microphone mounted on a small standUsed for fixed positions
Often seen in:Game showsSpeechesBoard rooms
Churches16Slide17
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Headset Microphone
Gives talent the freedom of movement while keeping the mic close to the mouth
Sometimes includes an earphone for talkback
Important for loud arenas and stadiumsUsed by sportscasters, musicians/performers and public speakersSmall, wireless headsets with no earphone are sometimes called “countryman” mics
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Wireless Microphones
Involves a microphone with a transmitter and a wireless receiver
Can come in any style
Lav
, headset, handAllows complete freedom of movement without wiresTransmits through frequency bands
UHF
Least interference
More expensive
VHF
Cheaper
Most interference
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s Education Agency, 2012. All rights reserved. Images and
other multimedia content used with permission.
Windscreens
Designed to let normal sound frequencies through and filter out wind noiseMade of acoustic foam rubber
WindsockUsed for shotgun micsRagged cloth that is pulled over the windscreen
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