PC Audio has been a market that hasn?t seen much change in the past year as the graphics and CPU. There was the boom of Envy 24HT cards being released for the low, mid, and high end sectors. Creative Labs also introduced their Audigy 2 ZS, which was a 7.1 version of their Audigy 2. We also saw Turtle Beach get back in the game; with disappointing results. Aside from the above mentioned, there were no real exciting innovations.

Then there?s AC?97, a low cost audio solution for motherboard vendors that was established in 1997. Over the years, AC?97 has evolved to include 6 channel audio. For most users, AC?97 audio was quite sufficient for everyday tasks; those seeking for higher quality audio simply laughed at the thought. While there was some excellent AC?97 codec?s such as Analog Device?s SoundMAX solutions, board vendors opted for the low cost Realtek ALC650/655 that would cause your ears to bleed.

At IDF 2003, Intel announced AC?97?s evolutionary successor; dubbed High Definition Audio. Formerly, HD Audio was only known as Azalia and was to launch with Grantsdale. As the name implies, HD Audio is a new standard for onboard audio that allows playback of audio at 32 bit/192 KHz (with proper codec support). This is a definite improvement over AC?97?s 20 bit/48 KHz. To support the high level of audio, bandwidth for HD Audio is at 48 MB/s per SDO, 24 MB/s per SDI, which is a significant upgrade over AC?97?s 11.5 MB/s max.

While AC?97 only supported a single in and out stream, HD Audio can support multiple in/out streams. Whereas AC?97 stability depended on the driver vendor, HD Audio utilizes a Microsoft bus driver that increases stability over existing solutions. To future proof the solution, HD Audio will also be supported by Microsoft?s Universal Audio Architecture, which is a requirement for Longhorn.

Aside from the hardware improvements, HD Audio has also been upgraded to support Dolby Pro Logic IIx, which will be a nice addition for Digital Home applications. To get a better grasp of High Definition Audio, we have conducted an interview with Intel?s Thomas Loza.

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• The interview (1 of 3)
• The interview cont... (2 of 3)
• Conclusion (3 of 3)