The card may use direct memory access to transfer the samples to and from main memory, from where a recording and playback software may read and write it to the hard disk for storage, editing, or further processing.Ĩ-channel DAC Cirrus Logic CS4382 placed on Sound Blaster X-Fi Fatal1tyĪn important sound card characteristic is polyphony, which refers to its ability to process and output multiple independent voices or sounds simultaneously. Some cards include a sound chip to support the production of synthesized sounds, usually for real-time generation of music and sound effects using minimal data and CPU time. In either case, the sound card uses an analog-to-digital converter to digitize this signal. Most sound cards have a line in connector for an analog input from a sound source that has higher voltage levels than a microphone. Input through a microphone connector can be used, for example, by speech recognition or voice over IP applications. Ī common external connector is the microphone connector. The output signal is connected to an amplifier, headphones, or external device using standard interconnects, such as a TRS phone connector. Sound cards use a digital-to-analog converter (DAC), which converts recorded or generated digital signal data into an analog format.
Sound cards are also used for computer-based communication such as voice over IP and teleconferencing.Ĭlose-up of a sound card PCB, showing electrolytic capacitors, SMT capacitors and resistors, and a YAC512 two-channel 16-bit DAC Typical uses of sound cards or sound card functionality include providing the audio component for multimedia applications such as music composition, editing video or audio, presentation, education and entertainment (games) and video projection. Sound processing hardware is also present on modern video cards with HDMI to output sound along with the video using that connector previously they used a S/PDIF connection to the motherboard or sound card. The integrated sound system is often still referred to as a sound card. Sound functionality can also be integrated onto the motherboard, using components similar to those found on plug-in cards.
The term sound card is also applied to external audio interfaces used for professional audio applications. Digital – RCA, TOSLink, S/PDIF or AES/EBUĬreative Labs (and subsidiary E-mu Systems)Ī sound card (also known as an audio card) is an internal expansion card that provides input and output of audio signals to and from a computer under control of computer programs.
PCMCIA interfaces ( PC Card, Expresscard).Higher bit-depth samples offer the potential for a higher signal-to-noise ratio.A Sound Blaster Live! Value card, a typical (circa 2000) PCI sound card.
In addition, ASIO supports 24-bit samples, unlike Windows NT 5.x MME and DirectSound which truncate 24-bit samples to the upper 16 bits, whereas Windows NT 6.x mixer provides 32-bit floating point output. Unlike KMixer, an unmixed ASIO output is "bit identical" or "bit perfect" that is, the bits sent to or received from the audio interface are identical to those of the original source, thus potentially providing higher audio fidelity. Its main strength lies in its method of bypassing the inherently high latency and poor-quality mixing and sample rate conversion of Windows NT 5.x audio mixing kernels (KMixer), allowing direct, high speed communication with audio hardware.
In this way ASIO offers a relatively simple way of accessing multiple audio inputs and outputs independently. Each layer that is bypassed means a reduction in latency (the delay between an application sending audio information and it being reproduced by the sound card, or input signals from the sound card being available to the application). Whereas Microsoft’s DirectSound is commonly used as an intermediary signal path for non-professional users, ASIO allows musicians and sound engineers to access external hardware directly.ĪSIO bypasses the normal audio path from a user application through layers of intermediary Windows operating system software so that an application connects directly to the sound card hardware.
Audio Stream Input/Output ( ASIO) is a computer sound card driver protocol for digital audio specified by Steinberg, providing a low-latency and high fidelity interface between a software application and a computer's sound card.