Digital car radio with surround sound
September 11, 2007 Billed as the next generation of automotive radio technology, DAB Surround was presented by the BMW Group in collaboration with the Fraunhofer IIS and Deutschlandradio at the IFA in Berlin. Digital Audio Broadcasting (DAB) offers CD quality sound and enables several radio programmes along with additional data to be broadcast on a single frequency, meaning cars can be fed with real-time information including traffic reports and local hazard warnings.
“The digital transmission of a radio signal has many advantages compared to analogue FM/VHF technology. It enables radio listening in crystal-clear CD quality. Moreover, the digital signal is more reliable as it can compensate for interference or transmission faults,” says Dr Christoph Grote, in charge of in-car information and communication at the BMW Group and an enthusiastic supporter of DAB.
Extensive shared-channel networks provide an added convenience for listeners by dispensing with regional frequency changes on long-distance journeys. Digital technology allows data to be sent “piggyback” fashion in far greater volumes than in the analogue realm. That means a wide range of services and information can be provided through radio, the bandwidth ranging from text and picture information on the radio programmes, to news, traffic and weather reports, all the way to local hazard warnings.
The reproduction of surround sound is also based on supplementary spatial sound information relayed over and above the conventional stereo signal. The requisite technology for broadcasting 5.1 surround sound to the vehicle is provided by the Fraunhofer Institute for Integrated Circuits IIS. This was showcased by a BMW X5 technology carrier at the Berlin fair which received a special Deutschlandradio broadcast DAB Surround format.
Cars with conventional DAB receivers will continue to receive the programme in good stereo quality, but mobile radio surround sound is not available in production cars. A DAB tuner for the reception of Digital Audio Broadcasting on the move is available as a special option on the models of the BMW 7 Series, BMW 6 Series, BMW 5 Series and BMW 3 Series, as well as the BMW X5 and the MINI (from model year 2007).
Digital signal availability
In Germany, more than 80 percent of the transmission area is equipped with radio masts for broadcasting digital radio programmes. Similarly Denmark, Norway, Great Britain and Switzerland also have virtually blanket DAB coverage. The EU requires its member states to pull the plug on analogue broadcasting by 2012, which means more and more broadcasters are currently going dual and providing analogue as well as high-quality digital programmes. Thanks to this parallel feed, a DAB tuner can automatically switch to analogue FM/VHF reception if the signal breaks up during a digital broadcast.
The BMW Group says it recognizes the future potential for this technology in terms of surround sound as well – though that will depend on what the broadcasters have to offer.
The cost of this optional BMW DAB tuner is 410 euros.