A
sound card (also known as an
audio card) is an internal
computer expansion card that facilitates the input and output of
audio signals to and from a computer under control of computer programs. The term
sound card
is also applied to external audio interfaces that use software to
generate sound, as opposed to using hardware inside the PC. Typical uses
of sound cards 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 functionality can also be integrated onto the
motherboard,
using basically the same components as a plug-in card. The best plug-in
cards, which use better and more expensive components, can achieve
higher quality than integrated sound. The integrated sound system is
often still referred to as a "sound card".
General characteristics
Most sound cards use a
digital-to-analog converter (DAC), which converts recorded or generated
digital data into an
analog format. The output signal is connected to an amplifier, headphones, or external device using standard interconnects, such as a
TRS phone connector or an
RCA connector.
If the number and size of connectors is too large for the space on the
backplate the connectors will be off-board, typically using a breakout
box, an auxiliary backplate, or a panel mounted at the front. More
advanced cards usually include more than one sound chip to support
higher data rates and multiple simultaneous functionality, for example
digital production of
synthesized sounds, usually for real-time generation of music and sound effects using minimal data and CPU time.
Digital sound reproduction is usually done with multichannel DACs,
which are capable of simultaneous digital samples at different pitches
and volumes, and application of real-time effects such as filtering or
deliberate distortion. Multichannel digital sound playback can also be
used for music synthesis, when used with a
compliance[clarification needed], and even multiple-channel emulation. This approach has become common as manufacturers seek simpler and lower-cost sound cards.
Most sound cards have a
line in connector for an input
signal from a
cassette tape or other sound source that has higher voltage levels than a microphone. The sound card digitizes this signal. The
DMAC transfers the samples to the main memory, from where a recording software may write it to the
hard disk for storage, editing, or further processing. Another common external connector is the
microphone connector, for signals from a
microphone or other low-level input device. Input through a microphone jack can be used, for example, by
speech recognition or
voice over IP applications.
Sound channels and polyphony
An important sound card characteristic is
polyphony, which refers to its ability to process and output multiple
independent voices or sounds
simultaneously. These distinct
channels
are seen as the number of audio outputs, which may correspond to a
speaker configuration such as 2.0 (stereo), 2.1 (stereo and sub woofer),
5.1 (surround), or other configuration. Sometimes, the terms
voice and
channel are used interchangeably to indicate the degree of polyphony, not the output speaker configuration.
For example, many older
sound chips could accommodate three voices, but only one
audio channel (i.e., a single mono output) for output, requiring all voices to be mixed together. Later cards, such as the
AdLib sound card, had a 9-voice polyphony combined in 1 mono output channel.
For some years, most PC sound cards have had multiple FM synthesis
voices (typically 9 or 16) which were usually used for MIDI music. The
full capabilities of advanced cards are often not fully used; only one
(mono) or two (
stereo)
voice(s) and channel(s) are usually dedicated to playback of digital
sound samples, and playing back more than one digital sound sample
usually requires a software
downmix at a fixed sampling rate. Modern low-cost integrated soundcards (i.e., those built into motherboards) such as
audio codecs like those meeting the
AC'97
standard and even some lower-cost expansion sound cards still work this
way. These devices may provide more than two sound output channels
(typically 5.1 or 7.1
surround sound),
but they usually have no actual hardware polyphony for either sound
effects or MIDI reproduction – these tasks are performed entirely in
software. This is similar to the way inexpensive
softmodems perform modem tasks in software rather than in hardware.
Also, in the early days of
wavetable synthesis,
some sound card manufacturers advertised polyphony solely on the MIDI
capabilities alone. In this case, the card's output channel is
irrelevant; typically, the card is only capable of two channels of
digital sound. Instead, the polyphony measurement solely applies to the
number of MIDI instruments the sound card is capable of producing at one
given time.
Today, a sound card providing actual hardware polyphony, regardless
of the number of output channels, is typically referred to as a
"hardware audio accelerator", although actual voice polyphony is not the
sole (or even a necessary) prerequisite, with other aspects such as
hardware acceleration of 3D sound,
positional audio and real-time DSP effects being more important.
Since digital sound playback has become available and provided better
performance than synthesis, modern soundcards with hardware polyphony
do not actually use DACs with as many channels as voices; instead, they
perform voice mixing and effects processing in hardware, eventually
performing digital filtering and conversions to and from the frequency
domain for applying certain effects, inside a dedicated DSP. The final
playback stage is performed by an external (in reference to the DSP
chip(s)) DAC with significantly fewer channels than voices (e.g., 8
channels for 7.1 audio, which can be divided among 32, 64 or even 128
voices).
Color codes
Connectors on the sound cards are colour-coded as per the
PC System Design Guide.
[1]
They will also have symbols with arrows, holes and soundwaves that are
associated with each jack position, the meaning of each is given below:
| Colour |
Function |
Connector |
symbol |
| |
Pink |
Analog microphone audio input. |
3.5 mm minijack |
A microphone |
| |
Light blue |
Analog line level audio input. |
3.5 mm minijack |
An arrow going into a circle |
| |
Lime green |
Analog line level audio output for the main stereo signal (front speakers or headphones). |
3.5 mm minijack |
Arrow going out one side of a circle into a wave |
| |
Brown/Dark |
Analog line level audio output for a special panning,'Right-to-left speaker'. |
3.5 mm minijack |
| |
Black |
Analog line level audio output for surround speakers, typically rear stereo. |
3.5 mm minijack |
| |
Orange |
Analog line level audio output for center channel speaker and subwoofer. |
3.5 mm minijack |
| |
Silver/Grey |
Analog line level audio output for surround side channels. |
3.5 mm minijack |
| |
Gold/Grey |
Game port / MIDI |
15 pin D |
Arrow going out both sides into waves |
History of sound cards for the IBM PC architecture
The
AdLib Music Synthesizer Card, was one of the first sound cards circa 1990. Note the manual volume adjustment knob.
ISA-8 bus.
Sound card Mozart 16 for
ISA-16 bus.
Sound cards for computers compatible with the
IBM PC were very uncommon until 1988, which left the single internal
PC speaker as the only way early PC software could produce sound and music. The speaker hardware was typically limited to
square waves,
which fit the common nickname of "beeper". The resulting sound was
generally described as "beeps and boops". Several companies, most
notably
Access Software,
developed techniques for digital sound reproduction over the PC
speaker; the resulting audio, while barely functional, suffered from
distorted output and low volume, and usually required all other
processing to be stopped while sounds were played. Other home computer
models of the 1980s included hardware support for digital sound
playback, or music synthesis (or both), leaving the IBM PC at a
disadvantage to them when it came to multimedia applications such as
music composition or gaming.
It is important to note that the initial design and marketing focuses
of sound cards for the IBM PC platform were not based on gaming, but
rather on specific audio applications such as music composition (
AdLib Personal Music System,
Creative Music System,
IBM Music Feature Card) or on speech synthesis (Digispeech
DS201,
Covox Speech Thing, Street Electronics
Echo). Not until Sierra and other game companies became involved in 1988 was there a switch toward gaming.
Hardware manufacturers
One of the first manufacturers of sound cards for the
IBM PC was
AdLib, who produced a card based on the
Yamaha YM3812
sound chip, also known as the OPL2. The AdLib had two modes: A 9-voice
mode where each voice could be fully programmed, and a less frequently
used "percussion" mode with 3 regular voices producing 5 independent
percussion-only voices for a total of 11. (The percussion mode was
considered inflexible by most developers; it was used mostly by AdLib's
own composition software.)
Creative Labs also marketed a sound card about the same time called the
Creative Music System. Although the
C/MS
had twelve voices to AdLib's nine, and was a stereo card while the
AdLib was mono, the basic technology behind it was based on the
Philips SAA 1099
chip which was essentially a square-wave generator. It sounded much
like twelve simultaneous PC speakers would have, and failed to sell
well, even after Creative renamed it the Game Blaster a year later, and
marketed it through Radio Shack in the US. The Game Blaster retailed for
under $100 and was compatible with many popular games, such as
Silpheed.
A large change in the IBM PC compatible sound card market happened with
Creative Labs' introduced the
Sound Blaster
card. The Sound Blaster cloned the AdLib, and added a sound coprocessor
for recording and play back of digital audio (likely to have been an
Intel microcontroller relabeled by Creative). It was incorrectly called a "DSP" (to suggest it was a
digital signal processor), a
game port for adding a
joystick,
and capability to interface to MIDI equipment (using the game port and a
special cable). With more features at nearly the same price, and
compatibility as well, most buyers chose the Sound Blaster. It
eventually outsold the AdLib and dominated the market.
Roland also made sound cards in the late 80s, most of them being high
quality "prosumer" cards, such as the MT-32 and LAPC-I. Roland cards
often sold for hundreds of dollars, and sometimes over a thousand. Many
games had music written for their cards, such as Silpheed and Police
Quest II. The cards were often poor at sound effects such as laughs, but
for music were by far the best sound cards available until the mid
nineties. Some Roland cards, such as the SCC, and later versions of the
MT-32 were made to be less expensive, but their quality was usually
drastically poorer than the other Roland cards.
The Sound Blaster line of cards, together with the first inexpensive
CD-ROM drives and evolving video technology, ushered in a new era of
multimedia computer applications that could play back CD audio, add recorded dialogue to
video games, or even reproduce
full motion video
(albeit at much lower resolutions and quality in early days). The
widespread decision to support the Sound Blaster design in multimedia
and entertainment titles meant that future sound cards such as
Media Vision's
Pro Audio Spectrum and the
Gravis Ultrasound had to be Sound Blaster
compatible
if they were to sell well. Until the early 2000s (by which the AC'97
audio standard became more widespread and eventually usurped the
SoundBlaster as a standard due to its low cost and integration into many
motherboards), Sound Blaster compatibility is a standard that many
other sound cards still support to maintain compatibility with many
games and applications released.
Industry adoption
When game company
Sierra On-Line opted to support add-on music hardware (instead of built-in hardware such as the
PC speaker and built-in sound capabilities of the
IBM PCjr and
Tandy 1000), what could be done with sound and music on the IBM PC changed dramatically. Two of the companies Sierra partnered with were
Roland and
Adlib, opting to produce in-game music for
King's Quest 4 that supported the
Roland MT-32 and
Adlib Music Synthesizer.
The MT-32 had superior output quality, due in part to its method of
sound synthesis as well as built-in reverb. Since it was the most
sophisticated synthesizer they supported, Sierra chose to use most of
the MT-32's custom features and unconventional instrument patches,
producing background sound effects (e.g., chirping birds, clopping horse
hooves, etc.) before the Sound Blaster brought playing real audio clips
to the PC entertainment world. Many game companies also supported the
MT-32, but supported the Adlib card as an alternative because of the
latter's higher market base. The adoption of the MT-32 led the way for
the creation of the
MPU-401/
Roland Sound Canvas and
General MIDI standards as the most common means of playing in-game music until the mid-1990s.
Feature evolution
Early
ISA
bus soundcards were half-duplex, meaning they couldn't record and play
digitized sound simultaneously, mostly due to inferior card hardware
(e.g.,
DSPs).
Later, ISA cards like the SoundBlaster AWE series and Plug-and-play
Soundblaster clones eventually became full-duplex and supported
simultaneous recording and playback, but at the expense of using up two
IRQ and DMA channels instead of one, making them no different from
having two half-duplex sound cards in terms of configuration. Towards
the end of the ISA bus' life, ISA soundcards started taking advantage of
IRQ sharing, thus reducing the IRQs needed to one, but still needed two
DMA channels. Many
PCI
bus cards do not have these limitations and are mostly full-duplex. It
should also be noted that many modern PCI bus cards also do not require
free DMA channels to operate.
Also, throughout the years, soundcards have evolved in terms of digital audio sampling rate (starting from 8-bit
11 025 kHz, to 32-bit,
192 kHz that the latest solutions support). Along the way, some cards started offering
wavetable synthesis, which provides superior
MIDI synthesis quality relative to the earlier
OPL-based solutions, which uses
FM-synthesis.
Also, some higher end cards started having their own RAM and processor
for user-definable sound samples and MIDI instruments as well as to
offload audio processing from the CPU.
For years, soundcards had only one or two channels of digital sound (most notably the
Sound Blaster
series and their compatibles) with the exception of the E-MU card
family, which had hardware support for up to 32 independent channels of
digital audio. Early games and
MOD-players
needing more channels than a card could support had to resort to mixing
multiple channels in software. Even today, the tendency is still to mix
multiple sound streams in software, except in products specifically
intended for gamers or professional musicians, with a sensible
difference in price from "software based" products. Also, in the early
era of wavetable synthesis, soundcard companies would also sometimes
boast about the card's polyphony capabilities in terms of MIDI
synthesis. In this case polyphony solely refers to the amount of MIDI
notes the card is capable of synthesizing simultaneously at one given
time and not the amount of digital audio streams the card is capable of
handling.
In regards to physical sound output, the number of physical sound
channels has also increased. The first soundcard solutions were mono.
Stereo sound was introduced in the early 1980s, and
quadraphonic sound came in 1989. This was shortly followed by
5.1 channel audio. The latest soundcards support up to
8 physical audio channels in the
7.1 speaker setup.
[citation needed]
Crippling of features
Most new soundcards
no longer have
the audio loopback device commonly called "Stereo Mix"/"Wave out
mix"/"Mono Mix"/"What U Hear" that was once very prevalent and that
allows users to digitally record speaker output to the microphone input.
Many users suspect the
RIAA
is responsible for colluding with or pressuring computer and soundcard
manufacturers to disable this and other features because of their
ability to be used for
copyright infringement
(although many legitimate uses exist for this feature), but no proof of
this currently exists. However, virtually no other answers exist as to
why computer and soundcard manufacturers have been discontinuing this
feature. No notice or information is usually given to consumers of the
exclusion or inclusion of the feature when purchasing or in
specifications.
Lenovo and other manufacturers fail to implement the chipset feature in hardware, while other manufacturers disable the
driver from supporting it. In some cases loopback can be reinstated with driver updates (as in the case of some Dell computers
[2]); alternatively software (
Total Recorder)
can be purchased to enable the functionality. According to Microsoft,
the functionality was hidden by default in Windows Vista (to reduce user
confusion), but is still available, as long as the underlying sound
card drivers and hardware support it.
[3]
Professional soundcards (audio interfaces)
Professional soundcards are special soundcards optimized for
low-latency multichannel sound recording and playback, including
studio-grade fidelity. Their drivers usually follow the
Audio Stream Input Output
protocol for use with professional sound engineering and music
software, although ASIO drivers are also available for a range of
consumer-grade soundcards.
Professional soundcards are usually described as "audio interfaces",
and sometimes have the form of external rack-mountable units using
USB,
FireWire,
or an optical interface, to offer sufficient data rates. The emphasis
in these products is, in general, on multiple input and output
connectors, direct hardware support for multiple input and output sound
channels, as well as higher sampling rates and fidelity as compared to
the usual consumer soundcard. In that respect, their role and intended
purpose is more similar to a specialized multi-channel data recorder and
real-time audio mixer and processor, roles which are possible only to a
limited degree with typical consumer soundcards.
On the other hand, certain features of consumer soundcards such as support for
environmental audio extensions (EAX), optimization for hardware acceleration in
video games,
or real-time ambience effects are secondary, nonexistent or even
undesirable in professional soundcards, and as such audio interfaces are
not recommended for the typical home user.
The typical "consumer-grade" soundcard is intended for generic home,
office, and entertainment purposes with an emphasis on playback and
casual use, rather than catering to the needs of audio professionals. In
response to this,
Steinberg (the creators of audio recording and sequencing software,
Cubase and
Nuendo) developed a protocol that specified the handling of multiple audio inputs and outputs.
In general, consumer grade soundcards impose several restrictions and
inconveniences that would be unacceptable to an audio professional. One
of a modern soundcard's purposes is to provide an AD/DA converter (
analog to digital/digital
to analog). However, in professional applications, there is usually a
need for enhanced recording (analog to digital) conversion capabilities.
One of the limitations of consumer soundcards is their comparatively
large sampling latency; this is the time it takes for the AD Converter
to complete conversion of a sound sample and transfer it to the
computer's main memory.
Consumer soundcards are also limited in the
effective sampling rates and bit depths they can actually manage (compare
analog versus digital sound)
and have lower numbers of less flexible input channels: professional
studio recording use typically requires more than the two channels that
consumer soundcards provide, and more accessible connectors, unlike the
variable mixture of internal—and sometimes virtual—and external
connectors found in consumer-grade soundcards.
Sound devices other than expansion cards
Integrated sound hardware on PC motherboards
In 1984, the first
IBM PCjr had a rudimentary 3-voice sound synthesis chip (the
SN76489) which was capable of generating three square-wave tones with variable
amplitude, and a pseudo-
white noise channel that could generate primitive percussion sounds. The
Tandy 1000,
initially a clone of the PCjr, duplicated this functionality, with the
Tandy TL/SL/RL models adding digital sound recording and playback
capabilities.
In the late 1990s many computer manufacturers began to replace plug-in soundcards with a "
codec" chip (actually a combined audio
AD/
DA-converter) integrated into the
motherboard. Many of these used
Intel's
AC'97 specification. Others used inexpensive
ACR slot accessory cards.
From around 2001 many motherboards incorporated integrated "real"
(non-codec) soundcards, usually in the form of a custom chipset
providing something akin to full
Sound Blaster compatibility, providing relatively high-quality sound.
However, these features were dropped when AC'97 was superseded by Intel's
HD Audio
standard, which was released in 2004, again specified the use of a
codec chip, and slowly gained acceptance. As of 2011, most motherboards
have returned to using a codec chip, albeit a HD Audio compatible one,
and the requirement for Sound Blaster compatibility relegated to
history.
Integrated sound on other platforms
Various non-IBM PC compatible computers, such as early
home computers like the
Commodore C64 (1982) and
Amiga (1985),
NEC's
PC-88 and
PC-98,
Fujitsu's
FM-7 and
FM Towns, the
MSX,
[4] Apple's
Macintosh, and
workstations from manufacturers like
Sun,
have had their own motherboard integrated sound devices. In some cases,
most notably in those of the Amiga, C64, PC-88, PC-98, MSX, FM-7, and
FM towns, they provide very advanced capabilities (as of the time of
manufacture), in others they are only minimal capabilities. Some of
these platforms have also had sound cards designed for their
bus architectures that cannot be used in a standard PC.
Several Japanese computer platforms, including the PC-88, PC-98, MSX, and FM-7, featured built-in
FM synthesis sound from
Yamaha by the mid-1980s. By 1989, the FM Towns computer platform featured built-in
PCM sample-based sound and supported the
CD-ROM format.
[4]
The custom sound chip on
Amiga,
named Paula, had four digital sound channels (2 for the left speaker
and 2 for the right) with 8 bit resolution (although with patches,
14/15bit was accomplishable at the cost of high CPU usage) for each
channel and a 6 bit volume control per channel. Sound Play back on Amiga
was done by reading directly from the chip-RAM without using the main
CPU.
Most arcade games have integrated sound chips, the most popular being
the Yamaha OPL chip for BGM coupled with a variety of DACs for sampled
audio and sound effects.
Sound cards on other platforms
The earliest known soundcard used by computers was the
Gooch Synthetic Woodwind, a music device for
PLATO terminals, and is widely hailed as the precursor to sound cards and MIDI. It was invented in 1972.
Certain early arcade machines made use of sound card to achieve
playback of complex audio waveforms and digital music, despite being
already equipped with onboard audio. An example of a sound card used in
arcade machines is the
Digital Compression System card, used in games from
Midway. For example,
Mortal Kombat II on the Midway T Unit hardware. The T-Unit hardware already has an onboard
YM2151 OPL chip coupled with an OKI 6295 DAC, but said game uses an added on DCS card instead.
[5] The card is also used in the arcade version of Midway and
Aerosmith's
Revolution X
for complex looping BGM and speech playback (Revolution X used fully
sampled songs from the band's album that transparently looped- an
impressive feature at the time the game was released).
MSX
computers, while equipped with built-in sound capabilities, also relied
on sound cards to produce better quality audio. The card, known as
Moonsound, uses a
Yamaha OPL4 sound chip. Prior to the Moonsound, there were also soundcards called
MSX Music and
MSX Audio, which uses
OPL2 and
OPL3 chipsets, for the system.
The 1977
Apple II series of computers, which did not have sound capabilities beyond a beep, could use the Sweet Micro Systems
Mockingboard (a name-play on
mockingbird),
essentially a sound card. Early Mockingboard models ranged from 3
voices in mono, while some later designs had 6 voices in stereo. Some
software supported use of two
Mockingboard cards, which allowed 12-voice music and sound. A 12-voice, single card clone of the
Mockingboard called the
Phasor
was made by Applied Engineering. In late 2005 a company called
ReactiveMicro.com produced a 6-voice clone called the Mockingboard v1
and also had plans to clone the Phasor and produce a hybrid card
user-selectable between
Mockingboard and
Phasor modes plus support both the SC-01 or SC-02
speech synthesizers[citation needed].
External sound devices
Devices such as the
Covox Speech Thing
could be attached to the parallel port of an IBM PC and feed 6- or
8-bit PCM sample data to produce audio. Also, many types of professional
soundcards (audio interfaces) have the form of an external FireWire or
USB unit, usually for convenience and improved fidelity.
Sound cards using the
PCMCIA Cardbus
interface were available before laptop and notebook computers routinely
had onboard sound. Cardbus audio may still be used if onboard sound
quality is poor, but Cardbus interfaces were superseded by
Expresscard on computers since about 2005. Some units are designed for mobile
DJs, providing separate outputs to allow both playback and monitoring from one system.
USB sound cards
USB sound "cards", sometimes called "audio interfaces", are usually external boxes that plug into the computer via
USB.
A USB audio interface may describe a device allowing a computer which
has a sound-card, yet lacks a standard audio socket, to be connected to
an external device which requires such a socket, via its USB socket.
The USB specification defines a standard interface, the USB audio
device class, allowing a single driver to work with the various USB
sound devices and interfaces on the market.
Even cards meeting the older, slow,
USB 1.1
specification are capable of high quality sound with a limited number
of channels, or limited sampling frequency or bit depth, but
USB 2.0 or later is more capable.
Uses
The main function of a sound card is to play audio, usually music,
with varying formats (monophonic, stereophonic, various multiple speaker
setups) and degrees of control. The source may be a CD or DVD, a file,
streamed audio, or any external source connected to a sound card input.
Audio may be recorded. Sometimes sound card hardware and drivers do not support recording a source that is being played.
A card can also be used, in conjunction with software, to generate arbitrary waveforms, acting as an audio-frequency
function generator. Free and commercial software is available for this purpose;
[6] there are also online services that generate audio files for any desired waveforms, playable through a sound card.
A card can be used, again in conjunction with free or commercial
software, to analyse input waveforms. For example, a very-low-distortion
sinewave oscillator can be used as input to equipment under test; the
output is sent to a sound card's line input and run through
Fourier transform software to find the amplitude of each harmonic of the added distortion.
[7]
Alternatively, a less pure signal source may be used, with circuitry to
subtract the input from the output, attenuated and phase-corrected; the
result is distortion and noise only, which can be analysed.
There are programs which allow a sound card to be used as an audio-frequency oscilloscope.
For all measurement purposes a sound card must be chosen with good
audio properties. It must itself contribute as little distortion and
noise as possible, and attention must be paid to bandwidth and sampling.
A typical integrated sound card, the Realtek ALC887, according to its
data sheet has distortion of about 80dB below the fundamental; cards are
available with distortion better than -100dB.
Driver architecture
To use a sound card, the
operating system (OS) typically requires a specific
device driver, a
low-level program
that handles the data connections between the physical hardware and the
operating system. Some operating systems include the drivers for many
cards; for cards not so supported, drivers are supplied with the card,
or available for download.
- DOS programs for the IBM PC often had to use universal middleware driver libraries (such as the HMI Sound Operating System, the Miles Audio Interface Libraries (AIL), the Miles Sound System
etc.) which had drivers for most common sound cards, since DOS itself
had no real concept of a sound card. Some card manufacturers provided
(sometimes inefficient) middleware TSR-based
drivers for their products. Often the driver is a Sound Blaster and
AdLib emulator designed to allow their products to emulate a Sound
Blaster and AdLib, and to allow games that could only use SoundBlaster
or AdLib sound to work with the card. Finally, some programs simply had
driver/middleware source code incorporated into the program itself for
the sound cards that were supported.
- Microsoft Windows
uses drivers generally written by the sound card manufacturers. Many
device manufacturers supply the drivers on their own discs or to
Microsoft for inclusion on Windows installation disc. Sometimes drivers
are also supplied by the individual vendors for download and
installation. Bug fixes and other improvements are likely to be
available faster via downloading, since CDs cannot be updated as
frequently as a web or FTP site. USB audio device class support is
present from Windows 98 SE onwards.[8] Since Microsoft's Universal Audio Architecture (UAA) initiative which supports the HD Audio, FireWire and USB audio device class standards, a universal class driver by Microsoft can be used. The driver is included with Windows Vista. For Windows XP, Windows 2000 or Windows Server 2003, the driver can be obtained by contacting Microsoft support.[9] Almost all manufacturer-supplied drivers for such devices also include this class driver.
- A number of versions of UNIX make use of the portable Open Sound System (OSS). Drivers are seldom produced by the card manufacturer.
- Most present day Linux distributions make use of the Advanced Linux Sound Architecture (ALSA). Up until Linux kernel
2.4, OSS was the standard sound architecture for Linux, although ALSA
can be downloaded, compiled and installed separately for kernels 2.2 or
higher. But from kernel 2.5 onwards, ALSA was integrated into the kernel
and the OSS native drivers were deprecated. Backwards compatibility
with OSS-based software is maintained, however, by the use of the
ALSA-OSS compatibility API and the OSS-emulation kernel modules.
- Mockingboard support on the Apple II is usually incorporated into
the programs itself as many programs for the Apple II boot directly from
disk. However a TSR is shipped on a disk that adds instructions to
Apple Basic so users can create programs that use the card, provided
that the TSR is loaded first.
Website sal Data/ Sumber Data : http://en.wikipedia.org/wiki/Sound_card
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