Sound cards are computer expansion cards that help in the input and output of audio signals to and from a computer that’s under control of computer programs. They are used to provide audio component for multimedia applications like music composition, education, presentation, editing video/audio and entertainment. Audio capability is built-in for many computers but some require additional expansion cards for the purpose.
Sound cards convert recorded or generated digital data into an analog format with digital-to-analog converter (DAC) and the output signal is connected to an amplifier or other external device by standard interconnects like TRS connector or an RCA connector. More advanced cards use more than one sound chip to provide higher data rates and multiple simultaneous functionalities.
Sound cards digitize signals from a cassette tape recorder or any sound source and store them on the hard disk for storage, editing or processing. This is done through a line in connector while the microphone connector is used by a microphone or other low level input device. This input is used by speech recognition software or Voice over IP applications. Polyphony is an important characteristic of sound cards.
Creative Labs Soundblaster 128 LIVE is the minimum for best audio quality, although many are around. Other good sound cards include Ensonic AudioPCI and TurtleBeach Fiji. Ensonic cards provide best performance to price ratio. Sound cards with S/P DIF output and external DA-converter yield top-quality audio.