Radio 5.1

DAB Surround® will lend a whole new quality to digital radio thanks to developments by the Fraunhofer Institute for Integrated Circuits IIS in Erlangen. Researchers there have devised the necessary techniques for processing and compressing the audio data. "When you listen to music on the radio, it will sound like you're sitting in a concert hall and not at your own breakfast table," says Matthias Rose of the IIS. The special feature of DAB Surround is that it doesn't require a higher data rate than stereo DAB to achieve this noticeably better sound experience. This is because the new MPEG Surround standard, developed largely by Fraunhofer engineers, compresses the six channels of a surround music track to the extent that they require no more memory than a compressed stereo signal. Another advantage is that radio broadcasters will be spared the expensive business of transmitting simultaneously in stereo and surround, as compression of the original 5.1 data automatically produces a stereo mix and sets parameters describing the surround sound. These parameters require only a few kilobits per second, and are aired by the broadcasters together with the stereo signal. While conventional receivers will ignore these extra data and play back the stereo signal as usual, future DAB Surround receivers will reproduce the original 5.1 sound – in perfect quality.

For broadcasters and programs that do not yet have any 5.1 content or would like to mix 5.1 and stereo source material, the IIS is offering another solution: the SX Pro® technique. This processes the stereo content in real time at the broadcasting station so that it can be smoothly incorporated in a 5.1 transmission. To do so, SX Pro® analyzes the sound characteristics of the stereo music signal and integrates the center and rear channels of a 5.1 system. This enlarges the optimal listening area and stabilizes the sound. As a result, even oldies from the 1970s and stereo concert recordings of well-known classical works can sail effortlessly over the airwaves in 5.1 Surround from now on. "Our mp3 Surround format also enables surround sound to be heard over the Internet – a chance for thousands of mp3 Web radio broadcasters to offer their listeners an extra bonus," says Rose. What is special about it is that the required bandwidth stays the same, thus avoiding higher broadcasting costs. ANTENNE BAYERN and ROCK ANTENNE are leading the way: Online, users can find links to the two broadcasters' Surround Web radio stations, and can listen to them using the mp3 Surround Player freeware or the latest version of WinAmp.

Source: Fraunhofer-Gesellschaft