Sound on the Web

Using Sound on a Web Site

Conveying informationpronounce a word or describe a product

Set a moodmusic to match the web page scene

Capture attention – a sound effect Explain a process Provide personal contact – voice, laugh

Physics of Sound – cycles per second – Hertz (Hz) or KHz

Sampled Sound

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) Not sampled – includes a code representing --

Musical note Loudness Length of time Type of instrument

Not compressed Generated by a synthesizer File extension .mid

Characteristics of sampled, compressed and Midi files Sampled files are very large depending on the highest

frequency being recorded and length of recording. voice – less than 8 kHz – sample 16kHz symphony orchestra – 22 kHz – sample 44 Hz, Mono

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

Played by user computer as it is received – not downloadedsaves bandwidthdoes not require storage space on user

computer live event soundsprevent copying file

Sound File Formats

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)

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/tts/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

Embedded – Media -> Plugin Linked – hyperlink to audio file – sound file

opens in separate window

Autoplay True, FalseController True, FalseLoop True, False

Audacity – sound utility