Download Audio Basics - Triad Video Production

Television Production & Broadcast
Journalism, 2nd Ed.
Ch. 6 Objectives
Explain the function of audio for television
Identify the most common use of each type of
microphone
Understand the importance of the pick-up pattern
classification when selecting a microphone
Recall the appropriate VU meter readings for both an
analog audio system and a digital audio system
Television Production & Broadcast
Journalism, 2nd Ed.
Ch. 6 Vocabulary
Automatic gain control (AGC)
Background sound
Boom
Boundary mic
Condenser mic
Dynamic mic
Fishpole boom
High impedance (HiZ)
Lapel mic (lav)
Low impedance (LoZ)
Mic level
Natural (nat) sound
Off-camera narration
Omni-directional mic
On-camera narration
Parabolic reflector mic
Pick-up pattern
Ribbon mic
Room tone
Shotgun mic
Uni-directional mic
Voice track
Wireless mic
Television Production & Broadcast
Journalism, 2nd Ed.
The Functions of Sound
for Television
Functions of sound for television:
Voice track
Music and sound effects
Environmental sound
Room tone
Television Production & Broadcast
Journalism, 2nd Ed.
Voice Track
Primary means of getting a message to the
viewer
Considered the most necessary audio of a
program
Sound created through dialogue or narration
Television Production & Broadcast
Journalism, 2nd Ed.
Two Forms of Narration
On-camera narration – viewer sees the narrator
speaking
Off-camera narration – viewer hears but does not see
the narrator
Also called voiceover (VO)
Narrator may be:
Reporter
On-the-street eyewitness
Television Production & Broadcast
Journalism, 2nd Ed.
o Automatic dialogue replacement (ADR) – see
Production Note on p. 133
o Music and sound effects help set the mood and
enhance the action of a program.
o Complete silence is artificial and should rarely, if
ever, be found in a TV program.
o Care must be taken to prevent the volume of
environmental sound from becoming distracting.
Television Production & Broadcast
Journalism, 2nd Ed.
Environmental Sounds
1. Background sound – environmental sound that
is not the most important sound in a shot
Must not overpower the foreground sound in a shot
Television Production & Broadcast
Journalism, 2nd Ed.
2. Natural (nat) sound – environmental sound that is
important to the topic of the story
May be the most important sound in the shot
Usually captured on B-roll, either before or after the shot
containing the voice track
Nat sound is environmental sound that helps call
attention to what a reporter is saying
It entices the viewer to continue paying attention to the
story
Only environmental sound that supports the story
Television Production & Broadcast
Journalism, 2nd Ed.
Room Tone
The sound present in a room, or at a location, before
human occupation
The “sound of silence” in the shooting environment
Record at least three minutes of existing
environmental sound
Useful when editing
Environmental (room tone) sound may be used to
cover unwanted sounds in the background of a
scene that were not noticed while shooting
Less noticeable audio edit than if true silence were
used
Television Production & Broadcast
Journalism, 2nd Ed.
Sound Frequency
Three groups of sound frequency:
1. Low-frequency (bass guitar, drum & tuba; bass
vocals)
2. Mid-range (trumpets, clarinets, French horns; alto
& tenor vocals)
3. High-frequency (flutes & piccolos; soprano
vocals)
Television Production & Broadcast
Journalism, 2nd Ed.
Microphones
Microphone – the piece of equipment that picks up
sounds in the air and sends them to the mixer or
recorder
How microphones work:
1. Sound waves in the air hit a thin surface inside the mic
(generating element or diaphragm) which vibrates
2. The vibration moves a tiny wire back and forth through
a magnetic field creating an electrical signal
3. This electrical signal is sent through the mic cable to
an amplifier or recorder
Television Production & Broadcast
Journalism, 2nd Ed.
Mics can be differentiated by examining the
frequencies of sound each best captures
Some mics pick up certain frequencies of sound
better than others
Audio engineer’s goal – match the right mic to
the right frequencies of sound
All microphones are not created equal – typically
get what you pay for
Low-cost gear often yields results that are less
than satisfactory
Television Production & Broadcast
Journalism, 2nd Ed.
Wired & Wireless Mics
Refers to how the signal gets from the mic to the
recorder
Wired mic - attached to the recorder by a cable
Very reliable
Greatest disadvantage—the cables
Television Production & Broadcast
Journalism, 2nd Ed.
Wireless mic - short cable that runs from the mic
to a radio transmitter
Transmitter sends the signal through the air, via a
radio wave, to a receiver that is on or near the
recorder
Receiver picks up the signal and sends it through a
short cable to the recorder
Wireless mics not the best choice for all
applications, however
Primary advantage – freedom of movement
Disadvantage – prone to interference from other
wireless devices at or near the same frequencies
Always keep a backup wired mic available
Television Production & Broadcast
Journalism, 2nd Ed.
Dynamic Microphones
Very rugged type of mic that has good sound
reproduction ability
Designed to pick up sounds best in normal speaking
voice frequencies
Not designed to mic musical instruments or
accompanying vocals
Do not pick up high- and low-frequency sounds as
effectively as mid-range sounds of speech
Television Production & Broadcast
Journalism, 2nd Ed.
Condenser Microphones
Mic that requires an external power supply
(usually a battery) to operate
Can pick up a greater range of sound
frequencies than dynamic mics
Good condenser mics are usually more
expensive
Television Production & Broadcast
Journalism, 2nd Ed.
Ribbon Microphones
Most sensitive of all mic types
In television applications, most commonly placed on
a talk show host’s desk
Now primarily used in music recording studios
Expensive disadvantage – fragility of generating
element (diaphragm)
Often must use a “pop filter” which protects the mic
from explosive “t” and “p” sounds, catches moisture
and rushes of air before they hit the diaphragm
Television Production & Broadcast
Journalism, 2nd Ed.
Non-Professional
Microphones
Microphone built into low-end camcorders
Should not be used in professional recording
scenarios
Very limited pick-up range
Often produces audio that sounds like the person
speaking has a bucket over his head
Picks up the grinding sound of the zoom lens
motor, the rubbing or knocking sounds of the
operator’s fingers and hands, and the sound of the
operator breathing
Television Production & Broadcast
Journalism, 2nd Ed.
Specialized Microphones
Boundary mic
Most commonly a condenser type mic
Becoming the most common way to mic an entire stage
or large room
Parabolic reflector mic
Very sensitive mic that looks like a satellite dish with
handles
Sensitivity of electronic parts directly related to the
cost
Often seen on the sidelines of professional football
games
Television Production & Broadcast
Journalism, 2nd Ed.
Pick-Up Pattern
Refers to how well a mic “hears” sounds from
various directions
Omni-directional mic – pick-up pattern that
captures sound from nearly every (omni) direction
equally well
Uni-directional mic (cartioid) – pick-up pattern
picks up sound from primarily one (uni) direction
Television Production & Broadcast
Journalism, 2nd Ed.
In a noisy environment, a directional mic is a
better choice for a narrator or reporter
The viewer may have a difficult time separating
the talent’s voice from the background sounds if
an omni-directional mic is used
Hypercardioid mic – narrower and longer pickup pattern than a cardioid mic
Supercardioid mic – even narrower pattern
Shotgun mic – even more directional still
(parabolic reflector mic is a shotgun mic)
Television Production & Broadcast
Journalism, 2nd Ed.
Mics on the Set
Hand-held microphone
Designed to be held in the hand
Can be placed on a stand or boom
Sometimes referred to as a stick mic
Television Production & Broadcast
Journalism, 2nd Ed.
Boom
A pole that is positioned over the set with a
microphone attached to the end of the pole
The goal is to get the mic as close to the talent as
possible without dipping the mic into the top of the
picture
Fishpole boom – type of boom that must be
physically held over the heads of talent
Lapel mic (lav or lavalier)
Smallest mic worn by talent
Attached about 6 inches from the mouth
Wired under clothing
Television Production & Broadcast
Journalism, 2nd Ed.
Guidelines for Handling
Mics
Never blow into a microphone
Do not shout into a microphone
Never let anyone put their lips directly on the
mic
Do not slap the head of the microphone to hear
the muffled thump through the speakers
Do not exhale directly into or inhale through the
mic
Never swing a mic by its cord
Television Production & Broadcast
Journalism, 2nd Ed.
Proper Use of
Microphones
Do not place lips directly on the surface of the mic
When using a hand-held, hold the mic firmly and keep
hand and fingers still
Get the mic close enough to your subject in an interview
When interviewing a child, get on his/her level
Never place an audio or mic cable beside an electrical
cable
Electrical cables produce magnetic fields which can cause
interference in the audio signal
Television Production & Broadcast
Journalism, 2nd Ed.
Impedance
In television, a microphone’s purpose is to
create a signal that is sent through a cable to be
recorded.
There are two kinds of signals that mics can
send:
High impedance (HiZ) – a typically inexpensive,
low-quality mic that cannot tolerate a cable longer
than 8’
Low impedance (LoZ) – high-quality, more costly
mic that can tolerate long cable lengths
Television Production & Broadcast
Journalism, 2nd Ed.
Three Levels of Audio
Mic level – the level of audio that comes from a
microphone
Designed to be sent to the “mic in” on a recorder
or mixer
Line level – level of audio between pieces of
audio equipment
Example – the level of audio going from the output
of a CD player to the input on an amp
Power level – the audio level from the output on
an amplifier to the speaker
Television Production & Broadcast
Journalism, 2nd Ed.
Mixers
Mic mixer – combines only the microphone
signals into a single- or dual-channel sound
signal
Audio mixer – designed to take the sounds from
a variety of sources such as mics, a CD player,
or tape player, and combine them into a single
sound signal that is sent to the recorder
Television Production & Broadcast
Journalism, 2nd Ed.
Automatic Gain Control
A circuit found on most consumer video
cameras that controls the audio level during the
recording process
Works best when it is part of a digital camcorder
as opposed to an analog recording situation
Television Production & Broadcast
Journalism, 2nd Ed.
Critical Note
It is critically important for whoever is recording
the audio to wear a good set of headphones that
cover the entire ear
This is the only way to accurately monitor the
quality of the audio being recorded