audio video production more sensitive better quality can be small cons: fragile and sensitive to...

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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Sound

Sound has two basic

characteristics:

Loudness - measured in

decibels

Frequency - measured in

Hertz

2



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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Copyright © Texas Education Agency, 2012. All rights reserved. Images and

other multimedia content used with permission.

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

4



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 - 15,000Hz5



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

7



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

Produces warm, rich sound

Very sensitive to rough

handling and moving air

Rarely used outside an audio

booth

9

LuckyLouie. RCA 44 Ribbon

Microphone. 4 November 2007.

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a44.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)

10

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

Advantages

Reporter can easily move it closer to interview

Singer can control intimacy of the sound by holding it closer

Field reporters – need a dynamic handheld mic

Singers - need condenser handheld Mics

Disadvantages

Can be distracting

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 a mic

Requires proper setup and placement

Clothing may rub mic or muffle sound



Lavalier Microphone 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 and over the talent’s shoulder near the collar

Clip mic to lapel, collar, or button flap

Use gaffers tape to keep the miccable 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

18



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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