Drawing on its years of experience in the high-end consumer and professional audio markets, Cirrus Logic Inc. introduced two new AC-97 v2.1-compliant codecs that promise the highest-quality audio for PCs and embedded systems. The new Crystal audio chips are also the industry's first audio solutions to provide Sony/Philips Digital Interface (S/PDIF) digital output, which enables easy digital connection with the growing number of consumer electronics products that support S/PDIF input.

The CS4299 is a complete audio solution designed to complement Intel's new core logic chip sets that will soon reach the market in millions of next-generation PCs. By providing the mixed- signal audio processing for the Intel 810/20-based systems, the Crystal audio codecs enhance PC sound capabilities for games, Internet audio files and CD-ROM playback.

The CS4297A, teamed with a PCI controller such as the Crystal CS4281, provides a two-chip audio solution for embedded systems such as set-top boxes, hand-held computers, and other devices that utilize the AC audio link, as well as for PCs where support of legacy peripherals is required.

Using Cirrus Logic's high-end proprietary audio patents to isolate digital noise from the audio signal path, the CS4299 and CS4297A filter out system noise. Another competitive advantage is lower distortion levels, resulting in much more lifelike sound reproduction. Both chips surpass all current audio quality standards, including as PC 98, PC 99, and AC 97 v2.1.

Unique S/PDIF Output
As the only audio codecs currently available with S/PDIF digital output, the new Crystal chips address the growing demand for easily connecting PCs to consumer electronics products. To meet or exceed consumer expectations for CD-quality audio, the codecs harness the full measure of a 20-bit architecture (20 bit stereo digital-to-analog, 18 bit stereo analog-to-digital). By delivering all 20 bits via the S/PDIF port, the codecs achieve an impressive 120 db dynamic range, thus matching professional quality levels.

To further improve sound quality, the CS4297A and CS4299 incorporate CrystalClear 3-D stereo enhancement. This feature helps broaden the stereo field, and is particularly useful for laptops and desktop computers with low-end speakers.

According to Scott McDonald, vice president of marketing for computer audio: "With the CS4299 and CS4297A, we are offering two solutions that will satisfy the audio system requirements for the majority of next-generation PCs, as well as systems where legacy integration is important. These products reinforce Cirrus Logic's leadership position in computer audio."

Addressing the reliability expectations of design engineers as well as consumers, the new chips feature the broadest range of drivers available on the market, with support for all major operating systems, including Windows 98, Windows 95, Windows NT 3.51 and 4.0, as well as the upcoming Windows 2000. Such extensive software support minimizes system compatibility issues, and increases consumer satisfaction. Software wavetable synthesis will also be included in the driver kit at no extra charge. Additional support will be available for Windows 3.1 and O/S2. Significantly, the CS4299 also features sample rate conversion in hardware. This enables games and other data-intensive applications with audio to run faster when sample conversion is off-loaded from the CPU.
In addition to S/PDIF output (either non-compressed PCM or compressed AC-3D data), both chips provide the following input/output options:

• dual stereo line-level analog outputs and one mono output
• two line-level mono inputs for a modem subsystem and an internal PC beeper
• four stereo and two mono line level inputs
• mono microphone input (with pre-amp) that is switchable from two external sources

Regular readers will know that I am not overly fond of the dB war that is foisted on us by vendors offering the "best dynamic range" or the "highest signal-to-noise ratio" in their latest AC'97-compliant codecs. What is significantly lacking in many of those is the offering of any features additional to those specified by Wintel. Why any manufacturer would want the definition of its products to be so dictated by others is beyond my ken. These Crystal parts go beyond that specification in a couple of refreshing ways, one of which will endear itself to a number of manufacturers who want to use the Sony/Philips Digital Interface. The interface is important for those who believe that high-quality analog audio does not belong inside a PC and that it should be handled externally.

The other significant change in the thinking of these products is the inclusion of sample-rate conversion on board, relieving the PC's processor from at least one burden when computionally-demanding applications are being run.

Cirrus Logic, with their Crystal products, is already a recognized, significant player -- one of three, in practice -- in the PC audio arena. These products will help keep them at the top of that group without sacrificing the need to offer products that will continue to operate in legacy conditions and with less than up-to-date operating systems. The parts are also priced at no nonsense levels for an industry that wants it that way.