The sound card's four main functions are: as a synthesizer (generating sounds), as a MIDI interface, analog-to-digital conversion (used, for example, in recording sound from a microphone), and digital-to-analog conversion (used, for example, to reproduce sound for a speaker). The three methods of sound synthesis are through frequency modulation (FM) technology, wavetable, and physical modeling
FM synthesis is the least expensive and least effective method. Sounds are simulated by using algorithms to create sine waves that are as close to the sound as possible. For example, the sound of a guitar can be simulated, although the result does not really sound very much like a guitar. Wavetable uses actual, digitally recorded sound samples stored on the card for the highest performance. Physical modeling is a new type of synthesizing, in which sounds are simulated through a complex programming procedure. Some sound cards can also have sounds downloaded to them.
Some sound cards have 3-D capabilities enabled by processors on the card that use mathematical formulas to create greater depth, complexity, and realism of sound. High quality audio can be produced through a system that uses the Universal Serial Bus (USB) and does not require a sound card. |