Erlangen, Germany (May 18, 2005)–5.1-channel surround sound in Digital Audio Broadcasting (DAB) can now be played back with standard stereo headphones with Ensonido, a new technology from Fraunhofer Institute for Integrated Circuits IIS. At High End 2005 in Munich in early May, Bayern Digital Radio and Fraunhofer IIS presented multi-channel sound for headphones in digital broadcasting for the first time.
So far, surround sound has been the domain of large loudspeaker setups in living rooms or theaters. Ensonido now provides nearly the same listening experience through a portable receiver and stereo headphones. In order to play surround sound over stereo headphones an acoustic model simulates the natural transmission of multi-channel sound from loudspeakers to the human ear.
Multichannel sound in DAB is achieved by the new “Spatial Audio Coding” technology (SAC). The Moving Pictures Expert Group (MPEG) is currently standardizing this technology as a multi-channel extension of existing perceptual audio codecs. Fraunhofer IIS significantly contributes to the standardization. The system is fully backward compatible and achieves an audio quality very close to a discrete multi-channel audio transmission. Unlike the latter, with SAC the data rate increases by just about 16 kBit/s for transmitting surround audio instead of stereo. In the upcoming MPEG standard the system will even work with spatial data rates as low as 5 kBit/s. Thus, SAC enables a smooth, compatible, and cost-effective introduction of multi-channel sound to DAB.