Structured Audio
Structured Audio is systhesized sound that is created by program applications that can process a alphanumeric/text language that describes the sound, and then direct the sysnthesizer to produce an audible sound. The languages allow for the construction of very complicated instruments.
CSound
CSound is a music programming / descriptive language. It is supported by Windows and Unix-based operating systems. Sound is produced through construction of sound sysnthesis components by CSound language code, which is entered into a text editor. The composer can write the performance and describe the qualities of the instruments in the performance. The instrument description is saved in a file and then the instrument can be played by MIDI controller. The application is presently in the public domain and is constantly being modified.
SAOL (Structured Audio Orchestra Language) and SASL (Structured Audio Score Language)
SAOL is a language that can be used to describe musical instrument parameters again based on creating sound synthesis components by mathematical equation. SASL is the companion language that controls the instruments created in SAOL. SAOL is incorporated into the MPEG-4 codec and is flexible enough to describe sysnthetic sound generation (additive, physical modeling, etc.) or manipulate a bank of digital audio sample files. SASL is the actual descriptive language that defines instruments and/or the entire performance by incorporating its data in the bit stream of the codec.