Anatomy of a Sound Card
A typical sound card has:
  • a digital signal processor (DSP) that handles most computations
  • a digital to analog converter (DAC) for audio leaving the computer
  • an analog-to-digital converter (ADC) for audio coming into the computer
  • read-only memory (ROM) or Flash memory for storing data
  • musical instrument digital interface (MIDI) for connecting to external music equipment (for many cards, the game port is also used to connect an external MIDI adapter)
  • jacks for connecting speakers and microphones, as well as line in and line out
  • a game port for connecting a joystick or gamepad

Current sound cards usually plug into a Peripheral Component Interconnect (PCI) slot, while some older or inexpensive cards may use the Industry Standard Architecture (ISA) bus. Many of the computers available today incorporate the sound card as a chipset right on the motherboard. This leaves another slot open for other peripherals. The SoundBlaster Pro is considered the de facto standard for sound cards. Virtually every sound card on the market today includes SoundBlaster Pro compatibility as a bare minimum.

Photo courtesy
Creative Labs SB4740 Sound Blaster 16 PCI

Often, different brands of sound cards from different manufacturers use the same chipset. The basic chipset comes from a third-party vendor. The sound card manufacturer then adds various other functions and bundled software to help differentiate their product.

Sound cards may be connected to:

Some of the current high-end sound cards offer four-speaker output and digital interface through a jack. For audiophiles, there is a new generation of digital sound cards. A digital sound card is practical for applications that need digital sound, such as CD-R and DAT. Staying digital without any conversion to or from analog helps prevent what is called "generational loss." Digital sound cards have provisions for digital sound input and output, so you can transfer data from DAT, DVD or CD directly to your hard disk in your PC.