One of the most popular plug-in known as LiveAudio, supports four most popular file types:

• .AIFF (Mac/SGI)
• .AU (Sun/NeXT)
• MIDI (Musical Instruments Digital Interface music format)
• .WAV (Microsoft Windows).

.AU and .WAV are probably easiest to find on the Internet. For instrumental background sounds on the Web pages, usage of MIDI is the best idea. Many popular sites like CNN support AIFF.

Other interesting plug-ins that deal with audio include ToolVox and Echospeech, that are used for transport of digitized speech at speeds of 9600 bps and over (compression up to 53:1), RapidTransit used for listening of highly compressed digitized music (compression up to 40:1), Crescendo and Crescendo Plus that support MIDI and many others.