Multimedia

2. What is "Audio"?
Audio means "of sound" or "of the reproduction of sound".
Specifically, it refers to the range of frequencies detectable by the
human ear — approximately 20Hz to 20kHz. It's not a bad idea to
memorize those numbers — 20Hz is the lowest-pitched (bassiest)
sound we can hear, 20kHz is the highest pitch we can hear.
Audio work involves the production, recording, manipulation and
reproduction of sound waves. To understand audio you must have a
grasp of two things:
Sound Waves: What they are, how they are produced and how we
hear them.
Sound Equipment: What the different components are, what they
do, how to choose the correct equipment and use it properly.

3. TECHNICAL NOTE: IN PHYSICS, SOUND IS A FORM
OF ENERGY KNOWN AS ACOUSTICAL ENERGY.

4.  The Field of Audio Work
 The field of audio is vast, with many areas of specialty.
Hobbyists use audio for all sorts of things, and audio
professionals can be found in a huge range of vocations.
Some common areas of audio work include:
 Studio Sound Engineer
 Live Sound Engineer
 Musician
 Music Producer
 DJ
 Radio technician
 Film/Television Sound Recordist
 Field Sound Engineer
 Audio Editor
 Post-Production Audio Creator

5. HOW SOUND WAVES WORK
Sound waves exist as variations
of pressure in a medium such as
air. They are created by the
vibration of an object, which
causes the air surrounding it to
vibrate. The vibrating air then
causes the human eardrum to
vibrate, which the brain interprets
as sound.
Sound waves travel through air in
much the same way as water
waves travel through water. In fact,
since water waves are easy to see
and understand, they are often
used as an analogy to illustrate
how sound waves behave.
It is a complex relationship involving a
vibrating object (sound source), a
transmission medium (usually air), a
receiver (ear) and a perceptor (brain).
Example banging drum.

6.  Sound is described in terms of two characteristics:
 Frequency
 Amplitude (or loudness)
 Frequency
 the rate at which sound is measured
 Number of cycles per second or Hertz (Hz)
 Determines the pitch of the sound as heard by our ears
 The higher frequency, the clearer and sharper the
soundthe higher pitch of sound

7.  Amplitude
 Sound’s intensity or loudness
 The louder the sound, the larger amplitude.
 The unit of regularity is called a cycle
 This is known as Hertz (or Hz) after Heinrich Hertz
 One cycle = 1 Hz
 Sometimes written as kHz or kiloHertz (1 kHz
= 1000 Hz)

8. Sound Wave Properties
All waves have certain properties. The
three most important ones for audio
work are shown here:
Wavelength: The distance between
any point on a wave and the equivalent
point on the next phase. Literally, the
length of the wave.
Amplitude: The strength or power of a wave
signal. The "height" of a wave when viewed as a
graph.
Higher amplitudes are interpreted as a higher
volume, hence the name "amplifier" for a device that
increases amplitude.

9.  Frequency: The number of
times the wavelength occurs in
one second. Measured in
kilohertz (Khz), or cycles per
second. The faster the sound
source vibrates, the higher the
frequency.
Higher frequencies are
interpreted as a higher pitch. For
example, when you sing in a
high-pitched voice you are
forcing your vocal chords to
vibrate quickly.

11.  Now here's the thing: All audio work is about
manipulating sound waves. The end result of your
work is this series of high and low pressure zones.
That's why it's so important to understand how they
work - they are the "material" of your art.