Hardware Reference
In-Depth Information
solid mid-range performance. Virtually all current chipsets have integrated audio. (See
Chapter 4
,
“
Motherboards and Buses
,
” for details.) Modern systems with integrated audio support at least one of
the following audio standards:
• AC'97
• Intel High Definition Audio (Azalia)
In most recent systems, Intel HDA is the preferred integrated audio standard, especially for DVD,
BD, and HDTV playback. However, many systems still include support for AC'97.
To learn more about AC'97 integrated audio, see the section “AC'97 Integrated Audio,” in Chapter
13, “Audio Hardware,” in
Upgrading and Repairing PCs
, 19th edition.
Intel “Azalia” HD Audio
Intel released Intel High Definition (HD) Audio in 2004 to deliver high-definition audio capable of
playing back more channels at higher quality than the previous AC'97-integrated audio standard.
Specifically, AC'97 supports up to six channels (5.1 surround audio) at 48KHz/20-bit, whereas HD
Audio supports up to eight channels (7.1 surround audio) at 192KHz/32-bit. Note that not all HD
Audio implementations support these maximums.
During its development, HD Audio was known by the code-name “Azalia,” and some vendors still
refer to it by this name. HD Audio not only can detect when devices are plugged in to an audio jack
but can also change the default assignment of the audio jack to match the device being inserted. This
helps to reduce audio failures caused by mismatched devices and jacks. Although HD Audio was
developed by Intel, it is also supported by most third-party audio codec vendors, including Realtek
(ALC861 family, ALC880 series, ALC892), IDT (92HDxxx series), Conexant (AD198x, AD188x,
CX20549 family, CX20551), and VIA (Vinyl VT1700 series, VT1800 series, VT 20xx series).
Most systems built in 2004 and later with integrated surround audio include support for HD Audio as
well as the older AC'97 audio standard.
HD Audio is the foundation for the Unified Audio Architecture (UAA) audio design used in Windows
Vista and later. To learn more about UAA, see the Audio Device Technologies for Windows website
Peripheral Configuration
,”
p.
301
.
Troubleshooting PC Audio Problems
Although PnP PCI and PCIe sound cards and integrated audio have eliminated the troublesome
hardware resource conflicts that once made adding audio to a PC a big headache, there are still many
possible sources of frustration with recording or playback. Use the following sections to help
troubleshoot your audio hardware.
Sound Card and Onboard Audio Problems
Like the common cold, sound hardware problems have common symptoms. Use the following
sections to diagnose your problem.
No Sound
If you don't hear anything from your computer, consider these solutions:
