17.10 Troubleshooting Sound Card Problems

Most sound card problems are a result of improper, defective, or misconnected cables, incorrect drivers, or resource conflicts. Sound card problems that occur with a previously functioning sound card when you have made no changes to the system are usually caused by cable problems or operator error (such as accidentally turning the volume control down). Sound card problems that occur when you install a new sound card (or when you add or reconfigure other system components) are usually caused by resource conflicts or driver problems. Resource conflicts, although relatively rare under Windows 9X/2000/XP in a PCI/Plug-N-Play environment, are quite common on machines running Windows NT and/or ISA because sound cards are resource hogs.

To troubleshoot sound problems, always begin with the following steps:

Verify that all cables are connected, that the speakers have power and are switched on, that the volume control is set to an audible level, and so on. In particular, if the sound card has a volume wheel on the back, make sure it is set to an audible level. It's often unclear which direction increases volume, so we generally set the wheel to a middle position while troubleshooting.
Shut down and restart the system. Surprisingly often, this solves the problem.
Determine the scope of the problem. If the problem occurs with only one program, visit the web sites for Microsoft, the software company, and the sound card maker to determine if there is a known problem with that program and sound card combination. If the problem occurs globally, continue with the following steps.
Verify that the sound card is selected as the default playback device. If you have more than one sound card installed, verify that the default playback device is the sound card to which the speakers are connected.
If your sound card includes a testing utility, run it to verify that all components of the sound card are operating properly.
If you have another set of speakers and/or a spare audio cable, substitute them temporarily to eliminate the speakers as a possible cause. If you have a set of headphones, connect them directly to Line-out on the sound card to isolate the problem to the system itself.

If the problem is occurring on a new system, or one in which you have just added or replaced a sound card, take the following steps:

Verify that the speakers are connected to the Line-out or Speaker jack, as appropriate, rather than to the Line-in or Microphone jack. Connecting speakers to the wrong jack is one of the most common causes of sound problems. We do it ourselves from time to time.
Verify that the CMOS Setup settings are correct for OS type. If you are running Windows 95/98/2000, OS type should be set to PnP Compatible (or similar words); if you are running NT4, it should be set to Non-PnP OS.
Use the procedures described in Chapter 1 to verify that no resource conflicts exist. If conflicts exist, remedy them and restart the system.
Check the troubleshooting sections of the Microsoft web site and the web sites for your motherboard and sound card manufacturer. Some sound cards, for example, have problems with motherboards with certain Via chipsets, while other sound cards have problems with AMD K6-family CPUs when used with certain AGP video cards.
Remove the drivers, restart the system, and reinstall the drivers from scratch.
Remove the drivers, shut down the system, and relocate the sound card to a different PCI slot. When the system restarts, reinstall the drivers from scratch.
If none of that works, suspect either a defective sound card or a fundamental incompatibility between your sound card and the rest of your system. Remove the drivers, shut down the system, remove the sound card, install a different sound card, and reinstall the drivers for it. If the replacement sound card is the same model and exhibits the same symptoms, try installing a different model of sound card.

If the problem occurs on a previously working system, take the following steps:

If you have recently added or changed any hardware, use the procedures described in Chapter 1 to verify that no resource conflicts exist.
If you have recently installed or uninstalled any software, it's possible that Setup installed DLLs that are incompatible with your sound card, or removed DLLs that your sound card or applications require. Remove the sound card drivers and reinstall them from scratch.
If sound still does not function properly, suspect a sound card failure.

Here are some specific common sound problems and their solutions:

No sound

This is probably the most common sound problem, and can have many causes. Following the troubleshooting steps listed previously should resolve the problem.

Scratchy or intermittent sound

This problem can also have many causes. Perhaps the most common is the sound card itself. Older and inexpensive sound cards often have poor audio quality, particularly FM synthesis models. Other common causes include a defective or low-quality audio cable, speakers placed too close to the monitor or other source of electrical noise, and the placement of the sound card within the system. If you have a choice, locate a sound card as far as possible from other expansion cards. Another possible cause is that some video card drivers are optimized for benchmark tests by having them keep control of the bus. The result can be intermittent drop outs and scratchiness in the sound.

Computer sounds are audible but audio CDs are not

Computer sound is digital, and is delivered directly to the sound card via the bus. Audio CDs produce analog sound, and require a separate internal cable joining the audio out connector on the back of the CD-ROM drive to the CD Audio connector on the sound card. If you do not have the necessary cable, you can temporarily fix the problem by connecting a standard stereo audio cable from the headphone jack on the front of the CD-ROM drive to the Line-in jack on the sound card. Note that recent motherboards and CD-ROM drives can deliver CD audio as a digital signal directly to the sound card, obviating the need for a separate CD-Audio cable.

Only one channel is audible

If you have another set of speakers or headphones, connect them directly to the sound card Line-out port to isolate the problem to either the sound card or the speakers. Roughly in order of decreasing probability, the most likely causes and solutions are:

The Windows audio balance control is set fully in one direction. Double-click the speaker icon in the System Tray and verify balance settings in the Volume Control dialog (or the replacement applet installed with your sound card drivers).
The balance control on your speakers, if present, may be set fully in one direction. This happens commonly when someone blindly attempts to change volume or tone and turns the wrong knob. Center the speaker balance control.
The audio cable is defective. Many audio cables, particularly those supplied with inexpensive speakers, are constructed poorly. Replace it with a high-quality, shielded audio cable, available for a few dollars from computer stores, audio specialty stores, and mass marketers such as Circuit City.
The audio cable is not fully seated in either the sound card jack or the speaker jack. Verify that the cable is fully seated at both ends.
You are using a mono rather than stereo audio cable to connect Line-out on the sound card to the speakers. Replace the cable.
The sound card driver is not installed, is installed improperly, or is the wrong driver. Some sound cards may function partially under these conditions, and the most common symptom is single-channel audio. Uninstall any driver currently installed, and then reinstall the proper driver.
Although it is rare, we once encountered a set of amplified speakers with one channel dead and the other working. Replace the speakers.

After installing a sound card, your PC speaker no longer works

This is by design in some sound cards. Installing the card and driver intentionally disables the PC speaker and routes sounds that would ordinarily go to the PC speaker to the sound card instead.

Windows suddenly loses sound

On Windows systems with properly configured and functioning sound cards, sound may disappear entirely for no apparent reason. This has happened to us on many different systems, using different motherboards and sound cards. The sound card still shows as installed, and everything appears perfectly normal, but the system simply stops sending audio to the speakers. This problem may or may not be accompanied by the speaker icon disappearing from the system tray. We have no idea what causes this, and we've never been able to get a satisfactory explanation from Microsoft. Restarting the system normally solves the problem, until next time. On systems in which "next time" is all too frequent, we have occasionally had some success by removing and then reinstalling the sound drivers.

The system locks up when you boot or bluescreens immediately after booting

This problem normally results from a severe resource conflict or an improperly installed card. Verify first that the card is seated fully. If it is, boot the system in Safe Mode (Windows 9X: press F8 during boot) or using the Last Known Good Configuration (Windows NT: press the spacebar when prompted). With the system booted, determine which devices and resources are conflicting, resolve the conflicts, and restart the system.