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Brief introduction to soundcard

Soundcards
[Δ] Soundcards Get picture of the breakdown of a soundcard Sound is a relatively new capability for PCs because no-one really considered it when the PC was first designed. The original IBM-compatible PC was designed as a business tool, not as a multimedia machine, so it's hardly surprising that nobody thought of including a dedicated sound chip in its architecture. Computers, after all, were seen as calculating machines; the only kind of sound necessary was the beep that served as a warning signal. For years, the Macintosh has had built-in sound capabilities far beyond the realms of beeps and clicks, but PCs with integrated sound are still few and far between. That's why PCs continue to require an add-in board or sound card to produce decent quality sound. The popularity of multimedia applications over the past few years has accelerated the development of the sound card, and the increased competition between manufacturers has led to these devices becoming cheaper and more sophisticated. Today's cards don't only make games and multimedia applications sound great but with the right software users can also compose, edit and print their own music as well as learn to play the piano, record and edit digital audio, and play audio CDs. Standards The hardware configuration of the AdLib soundcard was the first standard of importance, but it has been Creative Labs' SoundBlaster cards that have led the way in the establishment of a much-needed standard for digital audio on PC. Creative maintained its lead by following its 8-bit product with a 16-bit family, the user friendly AWE32 fulfilling the wish lists of several years' worth of existing users. Selling this as an OEM kit for PC manufacturers helped bring prices down and specifications up. The AWE64, launched in late 1997 and offering 64-note polyphony from a single MIDI device, 32 controlled in hardware and 32 in software, is the current benchmark. Most sound cards sold today should support the SoundBlaster and General MIDI standards and should be capable of recording and playing digital audio at 44.1kHz stereo. This is the resolution at which CD-Audio is recorded, which is why sound cards are often referred to as having 'CD-quality' sound. As well as producing sound, sound cards double-up as CD-ROM interfaces, supporting the three proprietary interfaces for Sony, Mitsumi and Panasonic drives in addition to the increasingly popular SCSI and IDE/EIDE standards. They also have an audio connector for CD-audio output. The rationale for providing CD-support on sound cards is that it allows a PC to be upgraded to 'multimedia' capability by the addition of a single expansion card. Components The modern PC sound card contains several hardware systems relating to the production and capture of audio, the two main audio subsystems being for digital audio capture and replay and music synthesis along with some glue hardware. The replay and music synthesis subsystem produces sound waves in one of two ways: through an internal FM synthesiser or by playing a digitised, or sampled, sound. The digital audio section of a sound card consists of a matched pair of 16-bit digital-to-analogue (DAC) and analogue-to-digital (ADC) converters and a programmable sample rate generator. The computer reads the sample data to or from the converters. The sample rate generator clocks the converters and is controlled by the PC. While it can be any frequency above 5kHz, it's usually a fraction of 44.1kHz. Most cards use one or more Direct Memory Access (DMA) channels to read and write the digital audio data to and from the audio hardware. DMA-based cards that implement simultaneous recording and playback (or full duplex operation) use two channels, increasing the complexity of installation and the potential for DMA clashes with other hardware. Some cards also provide a direct digital output using an optical or coaxial S/PDIF connection.

Soundcards

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Soundcards

Get picture of the breakdown of a soundcard

Sound is a relatively new capability for PCs because no-one really considered it when the PC was first designed. The original IBM-compatible PC was designed as a business tool, not as a multimedia machine, so it's hardly surprising that nobody thought of including a dedicated sound chip in its architecture. Computers, after all, were seen as calculating machines; the only kind of sound necessary was the beep that served as a warning signal. For years, the Macintosh has had built-in sound capabilities far beyond the realms of beeps and clicks, but PCs with integrated sound are still few and far between. That's why PCs continue to require an add-in board or sound card to produce decent quality sound.

The popularity of multimedia applications over the past few years has accelerated the development of the sound card, and the increased competition between manufacturers has led to these devices becoming cheaper and more sophisticated. Today's cards don't only make games and multimedia applications sound great but with the right software users can also compose, edit and print their own music as well as learn to play the piano, record and edit digital audio, and play audio CDs.

Standards
The hardware configuration of the AdLib soundcard was the first standard of importance, but it has been Creative Labs' SoundBlaster cards that have led the way in the establishment of a much-needed standard for digital audio on PC. Creative maintained its lead by following its 8-bit product with a 16-bit family, the user friendly AWE32 fulfilling the wish lists of several years' worth of existing users. Selling this as an OEM kit for PC manufacturers helped bring prices down and specifications up. The AWE64, launched in late 1997 and offering 64-note polyphony from a single MIDI device, 32 controlled in hardware and 32 in software, is the current benchmark.

Most sound cards sold today should support the SoundBlaster and General MIDI standards and should be capable of recording and playing digital audio at 44.1kHz stereo. This is the resolution at which CD-Audio is recorded, which is why sound cards are often referred to as having 'CD-quality' sound.

As well as producing sound, sound cards double-up as CD-ROM interfaces, supporting the three proprietary interfaces for Sony, Mitsumi and Panasonic drives in addition to the increasingly popular SCSI and IDE/EIDE standards. They also have an audio connector for CD-audio output. The rationale for providing CD-support on sound cards is that it allows a PC to be upgraded to 'multimedia' capability by the addition of a single expansion card.

Components
The modern PC sound card contains several hardware systems relating to the production and capture of audio, the two main audio subsystems being for digital audio capture and replay and music synthesis along with some glue hardware. The replay and music synthesis subsystem produces sound waves in one of two ways: through an internal FM synthesiser or by playing a digitised, or sampled, sound.

The digital audio section of a sound card consists of a matched pair of 16-bit digital-to-analogue (DAC) and analogue-to-digital (ADC) converters and a programmable sample rate generator. The computer reads the sample data to or from the converters. The sample rate generator clocks the converters and is controlled by the PC. While it can be any frequency above 5kHz, it's usually a fraction of 44.1kHz.

Most cards use one or more Direct Memory Access (DMA) channels to read and write the digital audio data to and from the audio hardware. DMA-based cards that implement simultaneous recording and playback (or full duplex operation) use two channels, increasing the complexity of installation and the potential for DMA clashes with other hardware. Some cards also provide a direct digital output using an optical or coaxial S/PDIF connection.