audio 1 - microphones

8/8/2019 AUDIO 1 - Microphones

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Sound


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Picture vs. Sound

Unless you are making a silent picture,

Sound is more importantthan picture.

How long would you watch a movie, TV

show with bad or no audio?

Have you ever listened to a show while doing

something else and still enjoyed it?


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Whatis sound

Sound is the vibration of air molecules


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SOUND

Sound travels in waves


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SOUND

Sound travels in waves


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WAVES: Length

Wavelength: The

distance between

any point on a waveand the equivalent

point on the next

phase. Literally, the

length ofthe wave.


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WAVES: Amplitude

Amplitude: The strengthor power of a wavesignal. The "height" of a

wave when viewed as agraph.

Higher amplitudes =

higher volumehence the name"amplifier" for a devicewhichincreases

amplitude.


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WAVES: Frequency

Frequency: The

number oftimes the

wavelength occurs in

one second. Measuredin kilohertz (Khz), or

cycles per second.

Frequency is how closetogetherthe waves are.

Frequencies are

interpreted as a pitch.

Higher frequencies are interpreted as ahigher pitch. For example, when yousing in a high-pitched voice you areforcing your vocal chords to vibratequickly.


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Phasing

The following table illustrates how sound waves (or any

other waves)interfere with each other depending on their

phase relationship:


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Phasing

Sound waves which are exactly in phase add

togetherto produce a stronger wave.

Sound waves which are exactly inverted, or 180degrees out of phase, cancel each other out and

produce silence. This is how many noise-

cancellation devices work.

Sound waves whichhave varying phase

relationships produce differing sound effects.


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NEXT

Microphone types


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Types of

Microphones


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Microphones

Microphones are a type oftransducer - a

device whichconverts energy from one

form to another.

Microphones convertacoustical energy(sound waves)into electrical energy (the

audio signal).


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Types of Microphones

Dynamic

Performance/Podium Handheld mic

CondenserPZM

Shotgun

Lavalier


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Dynamic vs. Condenser

Dynamic micis not battery powered

Condenserrequires Phantom power or a

battery.

Dynamic

Condensers


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Dynamic vs. Condenser

Dynamic are good forclose up work and can

be held by hand without noise (singing,

streetinterviews)

Condenserhave muchbetter reach &

sensitivity than dynamic mics

Dynamic

Condenser


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DYNAMIC

Dynamic Mics

use a moving

diaphram toconvert audio

signals into

electriccurrent.


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CONDENSER

Condenser Micsuses a capacitorto convert

acoustical energyinto electricalenergy .

Two movingplates with avoltage betweenthem createcurrent.


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Performance / Podium


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Handheld Performance Mic

TYPE: DYNAMIC

Least sensitive class of mic

Generates own electricity (no battery)

For human voice Low sensitivity and/ordirectional so as to

prevent feedback


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Speakers and

Headphonesperform the

opposite function

of microphones by

converting

electrical energy

into sound waves.


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ADVANTAGES

Short reach, low sensitivity

Extremely rugged, few parts/electronics

No batteries or remote powering needed No handling noise can be hand held


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Applications for Dynamic Mics

Live stage performance

Live Audience Question & Answer Isolated Narration orVoice-over

On-site Reporting

Eliminating noisy backgrounds


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Performance/Podium mic

PZM

Shotgun Lavalier


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Pressure Zone Mics


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Pressure Zone Mics

Aka PLATE orBoundary mic

TYPE: CONDENSER

mic

PZM mics are quiteunusual-looking.

They are flat anddon't really look likemicrophones at all.


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ADVANTAGES

Pick up large areas of

sound

Mounted to large

objects to create

sound

for example, atabletop or wall.


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Handheld

PZM

Shotgun Lavalier


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Shotgun/

Boom

Above equipment /

accessories for Boom

operator (wind sock,

zeppelin, boom pole)


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Boom Operation

very popularin film and

television production.

Adirectional micis

mounted on a boom

arm and positioned just

out ofcamera frame.

The cable is wrappedonce ortwice around

the boom arm.


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Shotgun

Usually pointingdown from abovewhen recording anactors dialogue(less unwantednoise).


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Shotgun

When used horizontally (like a rifle), they

pick up talent as well sound behind talent

(okay for sound effects, but rarely for dialogue).

Booming from below is a

bettercompromise less

noise.


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Shotgun Qualities

TYPE: Condenser mic Very directional on-axis Less directional Off-axis (around to the sides). Good for longer recording from longer

distances Battery (or phantom)Powered


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Lavalier


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Lavalier

TYPE: CondenserMic

clip-on

provides consistent

close-range sound

pickup.

Good for sit downinterview situations

(actor not moving).


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Lavalier- Problems

clothing noise, body

noise

Limitations of

movement due to cable

Time consuming /

intrusive to rig


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NEXT

Pickup patterns:

Some microphones pick up sound equally

from all directions, others pick up sound only

from one direction or a particular

combination of directions.


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PICKUPPA

TTERNS


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Pickup Patterns

Some microphones pick up sound

equally from all directions, others

pick up sound only from onedirection or a particular

combination of directions.


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Types of Pickup Patterns

Types of directionality are divided into

three main categories:

Uni-Directional (one direction)

Bi-Directional (two directions)

Omni-Directional (all directions)


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Two similartypes of Uni-directional

Cardioid

Hyper-cardioid

UNI-DIRECTIONAL


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CardioidCardioid means "heart-shaped"

UNI-DIRECTIONAL


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Acardioid michas a directional pickuppattern, so itis less sensitive to sounds

from behind, than itis to the sides andfront.

AHand Held

DYNAMIC michas a

Cardioid pattern

Cardioid

UNI-DIRECTIONAL


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This is exaggeratedversion ofthecardioid pattern. Itis very directionaland eliminates mostsound from thesides and rear.

Itis also sensitiveto the very back ofit as well

Hyper-Cardioid

UNI-DIRECTIONAL


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Very directional on-axis

Less directional as we work Off-axis

(around to the sides).

A shotgun micis Hyper-Cardioid

Hyper-Cardioid

UNI-DIRECTIONAL


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OMNI DIRECTIONAL

Capturessound equallyfrom all

directions.


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OMNI DIRECTIONAL

a lavalierhas an omni-directional pickup

pattern, so the direction itis pointing is not

significant.

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