Sound/audio card/adapter definition

A sound card (also know as audio card) or adapter is a computer module that produces sound wave signals, often electrical, for speakers or other physical sound-producing devices. They enable a computer or program to recreate or perform audio, from sound effects to music as well as capture audio via a microphone or another interface. Most sound adapters either comes as an expansion card that plugs into the computer main board, is embedded onto the main board or is an external peripheral that connects via USB.

The basic function of sound adapters is convert digital data into an analogue signal that drives a speaker or amplifier. One method of this is assigning the digital numbers (values) in a data stream as levels of amplitude of a wave or part of, with a fixed interval or frequency, which manipulates an output wave typically in an electrical current. Modern sound adapters can do more complex work, having their own memory and other components, such as to improve the quality of the audio reproduction and provide a synthesiser to generate music.