Up until now, the world of integrated audio chipsets was restricted to codecs based on the AC97 norm. Today this norm is synonymous with poor quality audio solutions. However, we should remember that it did standardize a computer’s minimum audio capacity and pushed sound cards up between the middle and high end range. The AC97 included a minimum of sound quality restitution, a complete separation between analogical and numerical flows, and universal compatibility with 8 KHz sampling rates intended for the release of Video DVDs. With time, though, theAC97 lost all its charm and is used with only basic model graphic cards such as the Hercules Muse 5.1 DVD, the Terratec Aureon 5.1 Fun and integrated chipsets.
It’s also important to take into account NVIDIA’s APU SoundStorm, which exceeded the AC97’s standard and showed that in the end it was possible to obtain good integrated audio quality with original capabilities. This was no longer an option, however, with the release of the nForce 3 250, and so we were left with several codecs such as the ALC650, ALC850, AD1885, STAC97XX or even CMI8738-6Ch, which were developed by Realtek, Analog Devices, Sigmatel or C-Media, respectively. These codecs helped to establish 5.1 sound and EAX 1.0 and 2.0 compatibility as a standard for integrated audio, but were still far below basic model sound cards such as the Audigy LS in terms of sound quality and functions.
Intel’s High Definition Audio (named Azalia before its release) is an evolution of the AC97. Its ambition is to represent a new standard for integrated sound found in every motherboard based on Intel’s chipsets, and for all motherboards in the future regardless of the chipset manufacturer. Motherboards based on the i915, i925 and i925XE will feature new HDA codecs manufactured by Realtek and C-Media. It has come to our attention that Sigmatel has also announced the release of a HDA chipset, the STAC9220/21, but apparently it’s not yet implemented on a motherboard. Also, you should know that HDA isn’t AC97 compatible. Because of a completely different architecture, a chipset isn’t able to control both AC97 chips (integrated modems, for example) and HDA codecs.
