Audio Hardware - Connecting PC Speakers and Completing the Installation
(Page 13 of 17 )
After the adapter card is installed, you can connect small speakers to the external speaker jack(s). Typically, sound cards provide 4 watts of power per channel to drive unpowered bookshelf speakers. If you are using speakers rated for less than 4 watts, do not turn up the volume on your sound card to the maximum; your speakers might burn out from the overload. You'll get better results if you plug your sound card into powered speakers—that is, speakers with built-in amplifiers. If your sound card supports a four-speaker system, check the documentation to see which jack is used for the front speakers and which for the rear speakers. To use the rear speakers for 3D audio, adjust the properties with the mixer control software supplied with your sound card.
Tip - If you have powered speakers but don't have batteries in them or have them connected to an AC adapter, don't turn on the speakers! Turning on the speakers without power will prevent you from hearing anything at all. Leave the speakers turned off and use the volume control built into your sound card's mixer software instead. Powered speakers sound better, but most small models can run without power in an emergency.
Some computer power supplies feature small jacks to provide power for computer speakers.
When the sound card installation is finished, you should have a speaker icon in the Windows System Tray. If the speaker icon (indicating the Volume Control) isn't visible, you can install it through the Control Panel's Add/Remove Programs icon. With Windows 9x/Me, select the Windows Setup tab and open the Multimedia section. Then, check the box labeled Volume Control. With Windows XP, open the Sounds and Audio Devices icon in Control Panel, click the Volume tab, and click the Place Volume icon in the taskbar box. In some cases you might be asked to insert the Windows CD-ROM if additional drivers are required to complete the installation.
If you use digital sound sources or output such as Dolby 5.1, CD digital, or S/PDIF, open the properties sheet for your mixer device and enable display of these volume controls.
Use the Volume Control to ensure your speakers are receiving a sound signal. The mixer sometimes defaults to Mute. You can usually adjust volume separately for wave (WAV) files, MIDI, microphone, and other components.
Using Your Stereo Instead of Speakers Another alternative is to patch your sound card into your stereo system for greatly amplified sound and for support of advanced Dolby Digital sound for DVD playback. Check the plugs and jacks at both ends of the connection. Most stereos use pin plugs, also called RCA or phono plugs, for input. Although pin plugs are standard on some sound cards or breakout boxes, most use miniature 1/8'' phono plugs, which require an adapter when connecting to your stereo system. For example, from Radio Shack you can purchase an audio cable that provides a stereo 1/8'' miniplug on one end and phono plugs on the other (Cat. No. 42-2481A). If you want to attach your sound card to Dolby 5.1 speakers, be sure you use cabling designed for the S/PDIF connectors on your sound card. Some might use RCA-type plugs, whereas others use an optical cable with a square end (also known as a Toslink connector).
Make sure that you get stereo—not mono—plugs, unless your sound card supports only mono. To ensure that you have enough cable to reach from the back of your PC to your stereo system, get a 6-ft. long cable.
Hooking up your stereo to an audio adapter is a matter of connecting the plugs into the proper jacks. If your audio adapter gives you a choice of outputs—speaker/headphone and stereo line-out—choose the stereo line-out jack for the connection. This will give you the best sound quality because the signals from the stereo line-out jack are not amplified. The amplification is best left to your stereo system. In some cases, you'll attach a special DIN plug to your audio adapter that has multiple connections to your stereo system.
Connect this cable output from your audio adapter to the auxiliary input of your stereo receiver, preamp, or integrated amplifier. If your stereo doesn't have an auxiliary input, other input options include—in order of preference—tuner, CD, or Tape 2. (Do not use phono inputs, however, because the level of the signals will be uneven.) You can connect the cable's single stereo miniplug to the sound card's stereo line-out jack, for example, and then connect the two RCA phono plugs to the stereo's Tape/VCR 2 Playback jacks.
The first time you use your audio adapter with a stereo system, turn down the volume on your receiver to prevent blown speakers. Barely turn up the volume control and then select the proper input (such as Tape/VCR 2) on your stereo receiver. Finally, start your PC. Never increase the volume to more than three-fourths of the way up. Any higher and the sound might become distorted.
Note - If your stereo speakers are not magnetically shielded, you might hear a lot of crackling if they are placed close to your computer. Try moving them away from the computer, or use magnetically shielded speakers.
Tricks for Using the Tape Monitor Circuit of Your Stereo
Your receiver might be equipped with something called a tape monitor. This outputs the sound coming from the tuner, tape, or CD to the tape-out port on the back; it then expects the sound to come back in on the tape-in port. These ports, in conjunction with the line-in and line-out ports on your audio adapter, enable you to play computer sound and the radio through the same set of speakers.
Here's how you do it:
Turn off the tape monitor circuit on your receiver.
Turn down all the controls on the sound card's mixer application.
Connect the receiver's tape-out ports to the audio adapter's line-in port.
Connect the audio adapter's line-out port to the receiver's tape-in ports.
Turn on the receiver, select some music, and set the volume to a medium level.
Turn on the tape monitor circuit.
Slowly adjust the line-in and main-out sliders in the audio adapter's mixer application until the sound level is about the same as before.
Disengage and re-engage the tape monitor circuit while adjusting the output of the audio adapter so that the sound level is the same regardless of whether the tape monitor circuit is engaged.
Start playing a WAV file.
Slowly adjust up the volume slider for the WAV file in the audio adapter's mixer application until it plays at a level (slightly above or below the receiver) that is comfortable.
Now you can get sounds from your computer and the radio through the receiver's speakers.
Different connectors might be needed if you have digital surround speakers and newer PCI-based sound cards. Check your speakers and sound card before you start this project.
 | This chapter is from Upgrading and Repairing PCs, 16th edition,by Scott Mueller. (Que Books, 2004, ISBN: 0789731738). Check it out at your favorite bookstore today. Buy this book now! |
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