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Multimedia for the Web:
Creating Digital Excitement
Multimedia Element — Sound
Chapter Concepts
Discuss the Use of Sound on the Web
Understand the Basic Principles of
Sound
Examine Digital Audio Sources
Explore Digital Audio Software
Discover Audio File Formats for the
Web
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Introduction
The element of sound can be
important to achieve the goals of a
multimedia Web site
Sound adds another dimension
If improperly created, sound files can
take too much time to download
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Introduction
Streaming audio: the sound file will
begin playing after part of the file is
downloaded
To help ensure effectiveness, it is
important to incorporate sound files
that are high quality, appropriate, and
consistent with the goals of the
multimedia Web site
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Discuss the Use of Sound
on the Web
Web has made it very easy for users
to purchase and download music
files directly from online music stores
Entertainment and game industry has
spurred the growth of computers with
multimedia capabilities
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Discuss the Use of Sound
on the Web
Web sites designed for entertainment
have background music that sets the
mood to light and cheery, or dark and
dreary
Audio can either be synched with the
occurrence of other objects in the
production, or it can serve as a trigger
when clicked
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Discuss the Use of Sound
on the Web
Providing controls (such as skip,
pause, mute, volume adjustment, etc.)
is an effective way of keeping users
involved and motivated
The decision to incorporate sound into
a multimedia Web site should have
solid reasoning behind it
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Discuss the Use of Sound
on the Web
Sounds are either content sounds or
ambient sounds
Content sounds furnish information
– Narration, dialogue are content sounds
Ambient sounds reinforce messages
and set the mood
Many splash screens or intro pages
use background music to set a mood
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Understanding the Basic
Principles of Sound
When you speak, vibrations, called
sound waves, are created
These sound waves have a recurring
pattern; an analog wave pattern called
a waveform
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Understanding the Basic
Principles of Sound
Amplitude: Distance between the
valley and the peak of a waveform
Decibel (dB): Smallest variation in
amplitude detected by the human ear
Frequency: Number of peaks that
occur in one second measured by the
distance between the peaks
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Understanding the Basic
Principles of Sound
Digitizing or Sound Sampling: The
process of converting analog sound
to numbers
Digital Audio: An analog sound that
has been converted to numbers
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Sound Quality
Two factors that determine sound
quality are sample rate and resolution
Sample Rate:
– Number of waveform samples per
second or the number of times the
sample is taken
– Measured in kilohertz, with 11 kHz, 22
kHz, and 44 kHz being the most
common sampling rates
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Sound Quality
Resolution:
– Number of binary bits processed for
each sound wave
– Sometimes referred to as sample size
– As the number of bits used to sample
the sound increases, the range and the
quality of the sound also improves
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Mono versus Stereo Sound
Mono sounds: Flat and unrealistic
compared to stereo sounds
Stereo sounds: Much more dynamic
and lifelike
Mono sound files are sometimes a
more appropriate choice on the Web
where storage and transfer are major
concerns
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Downloaded versus Streamed
Web Audio: Downloaded or streamed
Downloaded audio file must be
entirely saved to the user’s computer
before it can be played
Streaming: More advanced process
that allows sound file to be played as
it is downloading; before entire file is
transferred to the user’s computer
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Compression
Compression: Technique that
mathematically reduces size of a file
Beneficial for storing and transferring
sound files
Type of Compression applied impacts
quality of sound file and file size
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Examine Digital Audio
Sources
Clip audio gives access to
prerecorded digital audio clips of
music and sound effects
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Examine Digital Audio
Sources
Most of the sound on CDs has
been sampled at almost 45,000
samples per second, which is very
high quality
Be sure to carefully read the
licensing agreements that come
with clip audio
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Producing Digital Audio
In addition to using prerecorded audio
files, you can record, digitize, and
process your
own sound files
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Planning
Proper planning is critical if sound is
to be incorporated into multimedia
Web site
If the Web site is interactive,
flowcharts should distinguish between
which sounds are played as users
make different choices
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Recording
Minimally, a sound card and software
program are needed to digitize sound
The sound card samples or digitizes
the sound based on the sample rate
(11, 22, or 44 kHz) and resolution
(8- or 16-bit), and then produces the
digital approximation of the analog
signal
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Recording
Microphones translate analog signals
into electrical impulses
An analog-to-digital converter (ADC),
converts the electrical impulses to
numbers that can be stored,
understood, and manipulated by a
microprocessor
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Recording
MIDI: Standard format agreed on by
the major manufacturers of musical
instruments
MIDI standard was established so
musical instruments can communicate
sound information with one another
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Recording
To communicate, MIDI instruments
have “in” and “out” ports that enable
them to be connected to another
MIDI-ready device
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Processing
Today’s computers and synthesizers
make it possible for the average
person to produce high quality,
relatively inexpensive recorded sound
and music
Pieces of sound files may need to be
copied and moved or several sound
files may need to be mixed and
spliced together
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Assembling
Society of Motion Picture and
Television Engineers (SMPTE) was
developed to provide frame-accurate
video and audio data
By using professional SMPTE codes,
beats of music can be set to match
changes in video for all standard
video frame rates
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Delivering
To play sound on a computer system,
the user needs a sound card and
speakers, or a headset
The digital audio file is sent through a
digital-to-analog converter (DAC) so
that it can be heard
Important to test sounds under a
variety of different conditions
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Explore Digital Audio
Software
Traditional sound studio equipment is
utilized to record, mix, edit audio;
costs tens of thousands of dollars
With sound editing
and mixing software,
sound files can be
produced for much
less money
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Explore Digital Audio
Software
In the sound editing and mixing
industry, there are a number of
high-quality licensed and shareware
packages worth mentioning
BIAS: Berkley Integrated Audio
Software (BIAS); a leader in
developing solutions for sound editing
and mixing
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Explore Digital Audio
Software
Peak: Leading digital audio editor for
Macintosh platform; ideal for
manipulating sound files
Sony: Leading developer and
marketer of digital media and Internet
software tools
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Explore Digital Audio
Software
Sound Forge: Similar to Peak, but
designed for Windows platform
– Set the quality of sound file including
sample rate, the resolution or sample
size, file to be mono or stereo
Vegas: Frame-by-frame audio and
video synchronization; high-quality
streaming media, multitrack recording
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Explore Digital Audio
Software
ACID: music production software
offers sound professionals freedom to
create custom music
Digidesign Pro Tools: world’s leading
nonlinear audio editing workstation
and solutions
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Explore Digital Audio
Software
Pro Tools: most powerful and popular
high-end audio solution on the market
Adobe Audition: formerly Cool Edit;
digital audio software package that is
comprehensive, yet easy to learn
– Includes extensive top-quality digital
effects and it can mix multiple tracks
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Discover Audio File Formats
for the Web
All three media players (QuickTime,
RealPlayer, Windows Media Player):
– Equipped to open and display most
popular audio file formats
– Possess the ability to play live
streaming audio
QuickTime and RealPlayer: best
choices for streaming media
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Discover Audio File Formats
for the Web
Sound file formats include:
– AAC (Advanced Audio Coding):
MPEG-4; format of choice for Web
– AIFF or AIF (Audio Interchange File
Format): Macintosh waveform format
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Discover Audio File Formats
for the Web
Sound file formats include:
– AB (Audio/Basic): Sun audio format
developed by Sun Microsystems to
Play on Unix, NeXT, and Sun Sparc
workstations
– EA (Emblaze Audio): Sound format
developed specifically for Internet by
GEO for its Emblaze products
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Discover Audio File Formats
for the Web
– MIDI (Musical Instrument Digital
Interface): Internationally accepted file
format for storing MIDI data
– MP3 (MPEG—Audio Layer 3): Open
standard technology uses file
compression to create near-CD quality
audio files
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Discover Audio File Formats
for the Web
– Real formats (RA, RAM, RM): Excellent
compression, incredibly popular,
widespread support for streaming audio
– SWF: compressed Macromedia Flash
or Shockwave Flash file type designed
for animation
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Discover Audio File Formats
for the Web
– WAV: Waveform format; Commonly
used, supported format on Windows
– WMA (Windows Media Audio):
Powerful compression technology
delivering audio and video quality at
any bit rate
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Summary
Discuss the Use of Sound on the Web
Understanding the Basic Principles
of Sound
Sound Quality
Mono versus Stereo Sound
Downloaded versus Streamed
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Summary
Compression
Examine Digital Audio Sources
Producing Digital Audio
Planning
Recording
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Summary
Processing
Assembling
Delivering
Explore Digital Audio Software
Discover Audio File Formats
for the Web
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