New York - A promotional battle between satellite radio rivals XM and Sirius was kicked off with XM claiming that the sound quality of its service is superior to that of Sirius as it announced it has been employing a new state of the art audio encoding system called CT-aacPlus.
Sirius has long maintained that its satellite service offers the best sound quality due to the use of statistical multiplexing technology, which allocates more bandwidth to those channels that require it. For example a music station would be given more bandwidth than a talk station.
At a news conference held here by XM to announce the details of its codec, XM executive vice president of programming Steve Gavenas said XM does not need statistical multiplexing because CT-aacPlus encoding is so efficient that there is plenty of bandwidth for all channels. Claiming CT-aacPlus is 30 percent more efficient that other coding technologies he added, 'We believe our sound quality is better than Sirius.'
Gavenas added that XM's two satellites produce a signal, which is twice as strong as that of Sirius for improved geographical coverage.
XM had originally planned to use the PAC codec, but claimed it launched with CT-aacPlus because of its merits.
Sirius' reaction was blunt. 'The fact that XM has taken action to improve their sound quality is a reflection of the fact that they needed to do so,' said a spokesman. He noted, 'We're not going to get into a tit for tat discussion on the merits of each technology as both are complex and involved, but we are very pleased with the technology we have; it's been validated in the marketplace that is works very well. We have always felt that our system delivers superior quality sound because of they way it allocates bandwidth to the highs and lows.'
CT-aacPlus is a combination of Advanced Audio Coding (AAC), which combines audio encoding technology from AT&T, Dolby, Fraunhofer and Sony, with Spectral Band Replication (SBR) technology from Coding Technologies. It also uses technology from Neural Audio, which helps CT-aacPlus 'make decisions based on psychoacoustic models about what information to encode,' said XM.