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Sound

Sound is important in a multimedia presentation for the following reasons:

• reinforcement : pictures of an object can be enhanced with sound - for example a picture of a lion looks better accompanied by the sound of a lion's roar.
• enhancement : music playing can make a presentation more enjoyable.
• warnings or associations : a stong beep or ding is often used to indicate errors, while the sound played when windows shutsdown is familiar and reassuring.

Sounds may be stored on computers in two ways - as waves (or similar file formats) or as MIDI (or similar file formats). These two formats can be compared to bitmapped and vector file formats used in graphics. Waves are similar to Bitmaps, while MIDI files are similar to vector graphics.

Wave Files : digitised versions of analogue sound waves. These may be large files, depending upon the quality of the sound and the amount of compression used in storage. More information about Wave Files can be found here

MIDI Files : Musical Instrument Digital Interface - mathematical data used to drive the sound system directly. These are small files as the actual "sound" isn't stored, rather "instruction" for the sound card or musical instrument to "play" the sound. More information about MIDI Files can be found here.