Transcript in air - Sonoma Valley High School

Understanding Sound & Hearing







VOCABULARY
Tempranic Membrane ( eardrum)
Cochlea ( inner ear – magnifies sound )
Auditory Nerve ( converts to electric signal)
Sound Waves & Compression Waves
Decibel ( dB ) Power & Intensity
Hertz ( unit of sound measure )
To hear sound, your ear has to
do three basic things:
･Direct the sound waves into the hearing
part of the ear
･Sense the fluctuations in air pressure
･Translate these fluctuations into an
electrical signal
Ears Are Weird!
 Diagram - Human Ear
Ear Vs Mic (electric Signals)
 Inner Ear
 Amplification
System Via
Cochlea - Fluid
22 x more then
Ear Drum
The Amazing Ear
The Inner Ear To Electric Signals
How Sound Moves
 An object produces sound when it vibrates in matter,
such as earth, a liquid, water, gas, or typically air.
 Most of the time, we hear sounds traveling through
the air in our atmosphere.
 When something vibrates in the atmosphere, it moves
the air particles around it.
 Those air particles in turn move the air particles
around them, carrying the pulse of the vibration
through the air.
Sound Waves - Compression
Illustration:
Sine Waves
Air Molecules-Compression
Underwater Earthquake
Speed Of Sound
Fifteen Football Fields Per Second
1,236 kilometers per hour
(768 mph)
Speed Of Sound
How fast does sound travel?

Sound moves about 1500 meters per second in seawater.
( slightly less than a mile )
Thats approximately 15 football fields end-to-end in one second!!

Approximately a mile per second

(Sound moves much more slowly in
only 3 football fields a second).
air, at about 340 meters per second,
Sound Waves
Vocabulary _ Part Two






Crest
Trough
Wavelength
Waveform
Diaphragm
Foley Artist
Microphones convert energy from one form to anotheracoustical energy (sound waves) into electrical energy
(the audio signal).
 Typical Microphone
SOUND>MIC ( Diaphragm)>Signal dB
Sound Waves Vs Ocean Waves
Crests, Troughs & Wavelengths
Sound Waves Cont..
Audio Waveforms In Final Cut
DIAPHRAGMS & MICS
 Different types of microphone have different
ways of converting energy but they all share
one thing in common:
The diaphragm.
 This is a thin piece of material (such as
paper, plastic or aluminum) which vibrates
when it is struck by sound waves.
How Microphones Work
Cross Section - Typical Mic
Who Was Jack Foley?
Careers as a Foley Artist
SOUND / FOLEY PROJECT
( see teacher web page to print)
Brief Summary
 Sounds are vibrations caused by the movement of
air molecules through air, water, earth ( matter ).
• These vibrations enter the ear, press against the
ear drum ( tempranic membrane) and then enter
the middle and inner ear where they are amplified
up to 20x.
• The ear converts these vibrations into
“ELECTRICAL SIGNALS” for the Brain.
• MICROPHONES convert sound waves into
electrical signals for recording devices.