6.3 Adding Audio Capabilities with a Sound Card
6.3.2 USB, PCI, and built-in sound
The methods used to create audio are developed through the USB sound, PCI sound cards, and built-in sound chipsets found on the motherboard.

USB Sound
Universal Serial Bus (USB) is a hot-swappable interface that can be used to connect many different types of peripherals to a PC. One such popular peripheral is a USB speaker system. These speaker systems allow the USB port to act as a sound card. Plug-and-play is a major benefit of USB sound. There is no need for other configurations once the audio device is plugged into the interface. It has also been a standard for all Windows operating systems since 1996. With USB sound, the PC generates all of the information necessary to create sounds and music. The speakers then perform the digital-to-analog conversion. The drawback of USB sound is that it requires processing power to create audio and can in turn hamper the performance of the computer.

USB speaker systems require only the speakers, USB cable, and USB port to operate. The prices on these devices can vary from U.S. $40 to $400.

PCI Sound Cards
A Peripheral Component Interconnect (PCI) sound card is an adapter card with an audio processor that connects to a motherboard using a PCI slot. These cards use the PCI 32-/64-bit bus to input and output audio information. The on-board audio processor uses this information to create the audio, bypassing the computer processor and freeing up precious CPU cycles. PCI sound cards usually have multiple ports for connecting to other audio peripherals. External ports include speaker outputs, microphone inputs, and digital connectors. Internal interfaces are used to connect directly to CD-ROM and DVD drives. Remember, a PCI sound card is like any other adapter card in that it requires the use of an empty PCI slot and some of the computer resources. Most PCI sound cards use IRQ 5 as well as multiple memory ranges.

PCI sound cards come in many different varieties produced by many different manufacturers. Prices on basic sound cards can be between U.S. $10 and $100 while more advanced cards can cost well-over U.S. $1000.

Built-In Sound
Many motherboard manufacturers integrate both video and audio options into their products. The built-in sound has an audio processor physically located on a motherboard in the form of a single chip or chipset. In this manner, built-in sound has the advantages of both USB and PCI sound options. Since it is built-in, setup is simple as with USB. Since it uses an audio processor like a PCI sound card, the computer CPU does not process the audio information. Motherboards with built-in sound also include the common audio ports for speakers and a microphone.

One benefit of built-in sound is that the price of the complete package is less expensive. A separate sound card does not need to be purchased. The major drawback of built-in sound is that it is difficult (and sometimes impossible) to upgrade the audio capabilities. Upgrading built-in sound usually requires disabling the audio system and installing a PCI sound card.