{{Update, inaccurate=y, date=January 2012
On December 28, 2005,
XM Satellite Radio
XM Satellite Radio (XM) was one of the three satellite radio ( SDARS) and online radio services in the United States and Canada, operated by Sirius XM Holdings. It provided pay-for-service radio, analogous to subscription cable television. Its se ...
announced that it had teamed up with Neural Audio Corporation to introduce XM HD Surround, XM HD Surround broadcasts XM channels in 5.1 digital
surround sound
Surround sound is a technique for enriching the fidelity and depth of sound reproduction by using multiple audio channels from speakers that surround the listener ( surround channels). Its first application was in movie theaters. Prior to sur ...
. For a time XM broadcast a variety of special shows and live music performances in this format. According to th press release Denon, Onkyo,
Pioneer Electronics
commonly referred to as Pioneer, is a Japanese multinational corporation based in Tokyo, that specializes in digital entertainment products. The company was founded by Nozomu Matsumoto in January 1, 1938 in Tokyo as a radio and speaker repair ...
(USA) Inc., and
Yamaha Yamaha may refer to:
* Yamaha Corporation, a Japanese company with a wide range of products and services, established in 1887. The company is the largest shareholder of Yamaha Motor Company (below).
** Yamaha Music Foundation, an organization estab ...
will introduced home audio systems capable of playing XM HD Surround in 2006.
The 5.1 surround sound is encoded in the stereo wave for transmission and is thus compatible with any mono/stereo/matrix-style receiver. If played on a 5.1 audio set equipped with Neural Surround decoder, the
watermarks
A watermark is an identifying image or pattern in paper that appears as various shades of lightness/darkness when viewed by transmitted light (or when viewed by reflected light, atop a dark background), caused by thickness or density variations ...
(i.e. spatial cues) in the waveforms are detected and the signal is recovered to its original 5.1 form. The technology is similar to
parametric stereo
Parametric Stereo (abbreviated as PS) is an audio compression algorithm used as an audio coding format for digital audio. It is considered an Audio Object Type of MPEG-4 Part 3 (MPEG-4 Audio) that serves to enhance the coding efficiency of low band ...
, in which a mono signal is recovered to stereo. The
bitrate
In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time.
The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction ...
for XMHD surround broadcasts is ~70 kbit/s using
aacPlus
High-Efficiency Advanced Audio Coding (HE-AAC) is an audio coding format for lossy data compression of digital audio defined as an MPEG-4 Audio profile in ISO/IEC 14496–3. It is an extension of Low Complexity AAC (AAC-LC) optimized for ...
from
Coding Technologies
Coding Technologies AB was a Swedish technology company that pioneered the use of spectral band replication in Advanced Audio Coding. Its MPEG-2 AAC-derived codec, called aacPlus, was published in 2001 and submitted to the MPEG for standardizati ...