XM Drops PAC for CT-aacPlus
May 14, 2002 12:00 PM
Washington, DC - April 18, 2002 - At a press conference held in New York City, XM Satellite Radio unveiled it plans to use a customized CT-aacPlus audio encoding algorithm with neural audio optimization. XM staes that the new algorithm will provide superior sound quality remarkably close to compact disc.
CT-aacPlus is a third-generation audio encoding technology. CT-aacPlus is the combination of Advanced Audio Coding (AAC), now a global standard combining the work of AT&T, Dolby, Fraunhofer, and Sony with Coding Technologies' Spectral Band Replication (SBRM) technology.
Coding Technologies, a developer of perceptual audio compression and inventor of SBR, was formed through a merger between a Swedish group of researchers and experts from the renowned German Fraunhofer Institute, the inventor of MP3.
This combination of AAC and SBR, CT-aacPlus has been tested by high-profile audio experts from around the world. In a double-blind listening test, AAC alone has historically proven 33 percent more efficient compared to previous generations of competing algorithms. Double-blind listening tests conducted by the BBC, Deutsche Telekom and Robert Bosch GmbH have established that the CT-aacPlus combination is more than 30 percent more efficient than AAC. Based on superior test results, CT-aacPlus has been adopted by the International Digital Radio Mondiale (DRM) consortium and accepted by MPEG as the reference model for the upcoming version of MPEG-4.
In addition, the XM sound is further enhanced with Neural Audio, a Seattle-based research lab that pioneered future generation audio by merging neural networks with the physics of sound. Neural Audio's proprietary pre-processing software uses advanced neural network computing techniques to implement algorithms that are based on models of the brain's perception of sound.
Neural Audio created a customized version of its process, designed to enhance CT-aacPlus results by optimizing temporal and spectral elements prior to encoding, improving soundstage clarity, and increasing intelligibility. The unique combination of CT-aacPlus and Neural Audio algorithms enable XM to deliver a consistent, superior sound experience.
In addition, Neural Audio's Stereo Transcoder algorithm preserves the imaging and spatiality of stereo and surround-sound content that XM broadcasts. So XM customers with matrix-style surround sound equipment, including Dolby technology, can receive a full surround sound experience.
Previously, XM used the Perceptual Audio Coder algorithm, originally developed by Lucent Technologies and licensed to XM by Ibiquity Digital. Ibiquity will use PAC in its IBOC DAB system.