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Compression
Rarefaction
Hearing
Waveform
Frequency
Hertz
Amplitude
Volume
Analog
Digital
Distortion
Cardioid
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Hypercardioid
Supercardioid
Bidirectional
Omnidirectional
Condenser
Dynamic
Ribbon
PZM
XLR
TRS
RCA
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Audio Basics
◦ Sound
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 Compression
 Rarefaction
 Hearing

The Physics of Sound
◦ Frequency
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Hertz
 Human Hearing Range
Amplitude
Volume
Analog Recording
Digital Recording
Distortion (Audio)
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Microphone Polar Patterns
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Cardioid
Hypercardioid
Supercardioid
Bidirectional
Omnidirectional
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Condenser
Dynamic
Ribbon
PZM
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XLR
TRS
RCA
Cable Wrapping
Types of Mics
Cables
In this PowerPoint we will cover the physics of
sound, the different pick-up patterns used by
microphones, some common microphone
types, audio cables and their usage.
 To understand microphones however, first,
you must understand sound.

Objective(s): When you finish this section you should understand how
sound is represented, created and perceived.

Waveform
(a representation of sound)
◦ Physics – the shape of a wave, a graph
obtained by plotting the instantaneous
values of a periodic quantity against time

What is sound?
◦ Sound is a disturbance of air waves caused by the
vibration of an object. When an object moves it
causes air molecules to push together
(compression). As molecules bump into one another
they force other air molecules apart (rarefaction).
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Hearing
◦ When disrupted air waves enter our ears, our
organs of hearing translate them into nerve
impulses. The impulses travel to the brain, which
interprets them as a sound.
◦ A substance in which sound waves travel is called a
sound medium (air, water, solid). Where no sound
medium is present, there can be no sound.
If I wave my hand (object) in the air
(medium) can you hear it?
 Why / Why not?
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Frequency
◦ Physics – the number of cycles or
completed alternations per unit of time of a
wave or oscillation
 The standard unit of frequency measurement is hertz
(one cycle per second)
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Human hearing range: 15hz - 20kHz
◦ Generally: 20hz – 20kHz
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Amplitude
◦ Physics – the absolute value of the maximum
displacement from a zero value during one
period of an oscillation
If I wave my hand (object) in the air
(medium) can you hear it?
 Why / Why not?

◦ Proximity
◦ Frequency (Speed of vibration)
◦ Amplitude
◦ Human Hearing range: 20hz to 20 kHz
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Volume
◦ Science – A measure of loudness of intensity of a sound
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Analog Recording
◦ Refers to recording audio in a format of continuous
vibrations that are analogous to the original sound waves

Digital Recording
◦ A sequence of discrete samples taken from a continuous
sound (audio) waveform and converted into bits (ones and
zeros)

Distortion (audio)
◦ Distortion is created by warping (changing) the shape of the
original waveform
A microphone is an acoustic (sound created
without the use of electronics)-to-electric
transducer or sensor that converts sound into
an electrical signal
 Invented in 1876 (Emile Berliner) and first
used as a telephone voice transmitter
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Cardioid –
◦ Cardioid means "heart-shaped”
◦ Sound is picked up mostly from the front and to a
lesser extent the sides
◦ Very versatile, ideal for general use
◦ Handheld mics are usually cardioid

Hypercardioid
Exaggerated version of the cardioid pattern
Very directional, eliminates most sound from the
sides and rear
Often referred to as shotgun microphones
Sometimes confused with supercardioid

Supercardioid
A variation of the cardioid microphone that is
most sensitive at the front while rejecting
sounds entering 150 degrees to the rear
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Bi-Directional
Uses a figure-eight pattern
Picks up sound equally from two opposite
directions
Primarily used for interviewing. It can be
placed between two people facing one
another and pick-up each signal

Omnidirectional
Captures sound equally from all directions
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Variable Directionality
 Some microphones allow you to vary the directional
characteristics by selecting omni, cardioid or hypercardioid
(shotgun) patterns.
 This feature is sometimes found on video camera microphones,
with the idea that you can adjust the directionality to suit the
angle of zoom.

Microphone Directional Response Basics (2:43 min)
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Cardioid
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Hypercardioid
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Supercardioid
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Bi-Directional
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Omnidirectional
Objective(s): At the end of this section you should be able to describe
the types of microphones and the situations they are best suited for.

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Condenser means capacitor, an electronic
component which stores energy in the form of an
electrostatic field. A condenser microphone uses
a capacitor to convert acoustical energy into
electrical energy.
Condenser microphones are the most common
types of microphones you'll find in recording
studios. They have a much greater frequency
response and transient response - which is the
ability to reproduce the "speed" of an instrument
or voice. They also generally have a louder
output, but are much more sensitive to loud
sounds and prone to distortion.
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Much higher output levels due to built-in
amplifiers
Better transient response
◦ Faster response to rapid changes in spl
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Flatter frequency response
◦ Reproduces sound without color, especially in the high end
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Require batteries or phantom power from the
mixer
◦ Phantom Power is a method of powering microphones by
sending DC current (typically 48 volts) over the same mic
cable that carries the audio signal. "Phantom" is derived
from the fact that there is no visible power cord and the
voltage is not perceptible in the audio path.
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Condenser
Use for vocals and acoustic instruments
Sensitive: loud sounds or physical damage will
cause mic to stop working
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Compared to condenser microphones, dynamic
microphones are much more rugged. They are
especially resistant to moisture and other forms
of abuse, which makes them the perfect choice
onstage.
Dynamic microphones do not require their own
power supply like condenser microphones and
their sound quality is generally not as accurate, as
they have a limited frequency response, however,
this makes them well-suited, along with their
ability to withstand high sound pressure levels, for
recording loud sounds.
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Dynamic
◦ More durable than condensers or ribbons and less
expensive
◦ Narrow frequency response
◦ Live performance: stage, outdoors
◦ Use for rough, loud vocals
◦ Rugged, can handle rough handling, moisture and high
spl’s better than a condenser
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POPULAR
 Shure SM58
 Cardioid, used for vocals
 Shure SM57
 Cardioid, used for amplified or acoustic instruments
Type of Dynamic microphone
 Easily damaged
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Physical shocks can break the ribbon; sneezes,
coughs or slamming of case can stretch ribbon
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Generally does not use phantom power
Royer R122
◦ World’s first phantom power active ribbon mic
◦ Greater output than standard ribbons
◦ Used for quiet sources
 Acoustic instruments
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PZM
◦ Special type of condenser
 Consists of a small condenser

microphone mounted face 
down a short distance from the
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reflective boundary plate creating a pressure zone
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between the plate and the mic. The mic detects
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changes in the pressure zone, rather than the
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conventional method of detecting changes in the
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surrounding air pressure
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Works best when placed against a hard, flat
surface - often used in conference situations
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Elimination of interference from reflected
sound waves
Smooth frequency response
Good off-axis consistency
Strong output levels
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Condenser
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Use for vocals and acoustic instruments
Much higher output levels due to built-in amplifier
Require batteries or phantom power from the mixer
Faster response to rapid changes in spl
Reproduces sound more accurately than other mics
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Can withstand loud sounds
Do not require their own power supply
Not as accurate condensers due to a limited frequency response
Rugged
Moisture resistant
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Used for quiet sources
Bidirectional dynamic
Generally does not require and external power source (battery or phantom power)
Easily damaged
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Omnidirectional condenser
Eliminates interference from reflected sound waves
Strong output levels
Smooth frequency response
Dynamic
Ribbon
PZM
Objective(s): After completing this section you should understand the
different attributes of audio cables commonly used for video and be
able to identify them on site.
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XLR
◦ Balanced (3 Wires: hot, cold, ground))
◦ Used for microphones or equipment with
balanced ins and outs
◦ Usable lengths depend of type of mic being used
◦ Male (plug) / Female (jack) connectors
 Molded connectors - better
 Soldered and screwed connectors do not last as long
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TRS
(Tip, Ring, Sleeve / 1/4”)
◦ Also, TS and TRRS (iPod, iPhone)
◦ Unbalanced (2 Wires: hot, cold)
◦ Used for instruments, audio equipment,
unbalanced microphones
1
Sleeve
◦ Prone to interference
3
Tip
 Keep as short as possible
◦ Usually mono
4
 An exception: stereo headphone plugs
Ring
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RCA
Unbalanced
Keep as short as possible
 Wrapping
Follow natural bias - created by shielding
Over and under technique
Ties / Connectors

In the presentation we discussed the science
of sound, polar patterns, types of
microphones and audio cables.


Working in pairs, review the five polar
patterns discussed in this powerpoint.
Give at least one example of when each
would be the preferred pattern to use when
filming.
◦ Ex: An omnidirectional microphone would be better for recording ambient (natural)
sound because it would pick up all of the sound in the area without focusing on any
particular direction.

Submit to one document with both names on
it to Jupiter Grades “Polar Patterns”
assignment dropbox.