copyright © texas education agency, 2012. all rights reserved. images and other multimedia content...

Copyright © Texas Education Agency, 2012. All rights reserved. Images and other multimedia content used with permission.

Audio VideoProduction

Audio Basics

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Sound

Sound has two basic characteristics: Loudness - measured in

decibels Frequency - measured in

Hertz

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Loudness

dBSPL (sound pressure loudness) Measure of acoustic

power Sounds we can hear

with our ears 135 dB is considered

“threshold of pain” Ears ring Point 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 Conversation

60-80

Office Environment

45

Whisper 30

“Silent” studio 20

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Loudness dBm Unit of electrical power Measured with VU meters

Digital VU meter Analog VU meter

In live production, “0” is considered the maximum desirable sound level 0 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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Frequency Basic pitch of sound (how

high/low it is) Audible (hearing) range:

20Hz - 20,000Hz 20Hz - extremely low pitch,

rumble 20,000Hz - extremely high

pitch, higher than highest note of a violin

Common hearing range: 50Hz - 15,000Hz

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Acoustics Most sound booths

incorporate different types of soundproofing materials Hard 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)

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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 and rough handling Great for ENG (electronic news gathering)

Low Cost No power necessary

Cons: Larger and heavier Not the best choice for quality audio

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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 Expensive


Types of mics

Ribbon microphone Uses a small ribbon (rather

than coil) moving in a magnetic field

Similar to condenser mics in pickup quality and sensitivity

Produce warm, rich sound Very sensitive to rough

handling and moving air Rarely used outside an audio

booth

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LuckyLouie. RCA 44 Ribbon Microphone. 4 November 2007. <http://en.wikipedia.org/wiki/File:Rca44.png>.


How microphones “hear”

Microphone Pickup Patterns Omnidirectional

Picks up sound in all directions

Unidirectional (cardioid) Focused hearing in one

direction Cardioid - “heart-shaped”

pickup pattern Hypercardioid - narrow

pickup pattern with a “long reach” (for distances)

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Omnidirectional

UnidirectionalCardiod


How mics are used

Handheld mic Lavalier (lapel) mic Boom (shotgun) mic Desktop mic Headset mic

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Handheld Microphone

Held by the talent Allows for talent to control mic’s location

Reporter can easily move it closer to interview

Singer can control intimacy of the sound by holding it closer

Field reporters - need dynamic handheld (rugged, durable)

Singers - need condenser handheld (better sound quality)

Disadvantages Can 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 chin Advantages

Talent can move freely Mic 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 sound


Lavalier Microphone “Dressing” lapel mics (hiding wires)

Under clothing Have talent run microphone under

the shirt Clip mic to tie, lapel, collar or button

flap Careful of material rubbing mic or

obstructing sound Outside clothing

Run 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 pole Pole has shock-mount to

absorb all movement Can be held above talent

or at low angle below

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Desktop Microphone

Microphone mounted on a small stand

Used for fixed positions Often seen in:

Game shows Speeches Board rooms Churches

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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 stadiums Used by sportscasters,

musicians/performers and public speakers

Small, 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, hand Allows complete freedom of

movement without wires Transmits through frequency

bands UHF

Least interference More expensive

VHF Cheaper Most interference

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Windscreens Designed to let normal

sound frequencies through and filter out wind noise

Made of acoustic foam rubber

Windsock Used for shotgun mics Ragged cloth that is

pulled over the windscreen

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copyright © texas education agency, 2012. all rights reserved. images and other multimedia content...

Documents

multimedia content

original sound

frequencybasic pitch

quality audio

audio levels

acousticsmost sound

reverberation reverb

maximum desirable sound