(^544) PC Hardware: A Beginner’s Guide
reducedsounddistortionfromtheothercomponentsinsidethePC,buttherearealsodis-
advantages. One major disadvantage of USB speakers is that there are no input jacks that
can be used to connect external or internal devices like a CD-ROM or DVD player.
Magnetic Shielding
PC speakers typically sit fairly close to the PC. This is for two primary reasons: one, the cords
on the speakers are not very long, and two, the PC user wants the sound pointed directly at
him or her. Because of their closeness to the PC, PC speaker systems must be magnetically
shielded so that their magnets don’t distort the screen image on the PC’s monitor or possibly
damage the monitor permanently. This, more than any other reason, is why you should use
caution when using speakers not specifically designed for use on a PC.
Software
Software for audio devices comes on two levels: device control and playback control. Play-
back control software is used to control a PC device much like you would a stand-alone
playbackdevicelikeaCDorDVDplayer.Devicecontrolsoftwareconsistsofthedevicedriv-
ers that interface to the system BIOS and operating system on behalf of the audio device.Playback Software
Until recently, CD-ROM drives have had the basic CD-ROM controls on their front pan-
els. These controls include Play, Pause, Stop, Eject, and various forward and reverse con-
trols (see Figure 21-2). However, most of the newer CD-ROM and DVD-ROM drives no
longer have these controls, leaving control of the playback to software. Virtually all PC
operating systems, including all of Microsoft’s Windows versions and the many distribu-
tions of Linux, include basic software tools that can be used for recording, playing, and
mixing audio from different sources. Advanced tools for recording and manipulating
digital audio are available from a variety of software publishers.Figure 21-2. The display of the Creative Labs PlayCenter playback software