Transcript Sound on the Web - Plymouth State University

Sound on the Web
Using Sound on a Web Site
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Conveying information
 pronounce
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a word or describe a product
Set a mood
 music
to match the web page scene
Capture attention – a sound effect
 Explain a process
 Provide personal contact – voice, laugh
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Physics of Sound – cycles per
second – Hertz (Hz) or KHz
Sampled Sound
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Sound wave is digitized by sampling at twice the
highest frequency
Converted to a number representing the volume
(amplitude)
Stored in a computer file
Can represent any sound
called a wave file – usually a file extension .wav
Often compressed to reduce file size
Sampled Sound
Musical Instrument Digital Interface
(MIDI)
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Not sampled – includes a code representing - Musical
note
 Loudness
 Length of time
 Type of instrument
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Not compressed
Generated by a synthesizer
File extension .mid
Characteristics of sampled,
compressed and Midi files
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Sampled files are very large depending on the
highest frequency being recorded and length of
recording.
– less than 8 kHz – sample 16kHz
 symphony orchestra – 22 kHz – sample 44 Hz, Mono
 voice
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Compressed sound is sampled sound processed
to make the file smaller without sacrificing sound
quality
Midi are much smaller files but can represent
only music
Streaming Sound
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Played by user computer as it is received
– not downloaded
 saves
bandwidth
 does not require storage space on user
computer
 live event sounds
 prevent copying file
Sound File Formats
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Link
Preparing Sound for the Web –
Create a File
Use pre-recorded sound
 Record from microphone
 Use “text-to-sound” synthesizer
 Edit – mix sounds, cut, cut-and-paste, add
effects (Audacity)
 Record musical instrument sounds from
synthesizer (cannot be edited in computer)
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Download a Sound File
Google – free sound download
Sometimes the file may be a Zip file
•compressed
•combine several files in one
Zip files are shown as a folder with a zipper on it. It can be
automatically “unzipped” by double clicking on the folder and
selecting “extract” all files.
Text To Speech Conversion
•http://www.research.att.com/~ttsweb/tt
s/demo.php (note different voices)
•Audacity has a built-in converter
Including Sound on Web Page
(Same procedure as with a movie)
Passive – plays automatically
 Active – requires user action
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Embedded – Media -> Plugin
 Linked – hyperlink to audio file – sound file
opens in separate window
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Autoplay True, False
Controller True, False
Loop True, False
Audacity – sound utility