(^540) PC Hardware: A Beginner’s Guide
I
t wasn’t all that long ago when the only sounds a PC could produce—other than the
noise from the fan and hard disk drives, that is—were a few beeps and tones. Its lone
speaker was designed more to signal the user with diagnostic POST (Power-On
Self-Test) beep codes and operating system alerts than it was to reproduce high fidelity
state-of-the-art sound. Luckily, very few PCs today do not include an adequate to good
sound card and a set of speakers. PC sound systems vary from the simple playback of
games and system sounds to full-fledged Digital Audio Workstations (DAW) and PC-
based entertainment centers available that are capable of professional audio and video
production and post-production editing.
Video capability is something still new to the PC. Using the PC as a telephone where
you can hear the voice of the other party is one thing, but to actually participate in a
real-time see-and-say conversation, now that’s something right out of science fiction. To-
day’s computers can be configured to produce simple small frame video playback using
special software players, or they can be configured as a DAW for full motion video repro-
duction. Many PCs now come standard with a DVD (Digital Versatile Disc) player that
allows the user to watch full-length theatrical films right on their PC with all the sound
quality they can afford.
Sound on the PC
Today, sound is an inherent part of the PC. There are a variety of components common to
virtually all PC sound systems: a sound card, an amplifier, speakers, shielding, and driv-
ers and specialized software.Sound Card
The sound card, also known as an audio adapter, is an expansion card that adds the abil-
ity to record and play back sound from internal or external sources. The sound card inte-
grates all of the elements required to capture and reproduce sound. The elements of the
sound card are the inputs, outputs, and signal processors, which are the digital to audio
converters (DACs) and analog to digital converters (ADCs) required to convert sound
into or from digital data.
The sound card typically includes jacks (connectors) to accept sound inputs from a
microphone or another sound source, such as a CD player or the like, and output jacks for
speakers, amplifiers, or other sound recording equipment. Figure 21-1 shows how the
jacks on a sound card are placed so they extend outside of the system case.
Most sound cards, like the one in Figure 21-1, are typically ISA or PCI adapter cards.
However, the recent trend is to directly mount a sound chi pon the motherboard, which
eliminates the need for an audio adapter card.