Blaupunkt Car Stereo Listens & Learns

Just by "listening" to the car, this Blaupunkt DSP technology can mask ambient noise and bring Delco/Bose style acoustic correction to any automobile.
Blaupunkt has developed a car stereo that listens to its car. First, a process called Digital Sound Adjustment (DSA) uses a microphone to listen to the way the acoustic characteristics of the car distort the sound, and then it corrects for that distortion. Second, another process, called Dynamic Noise Covering (DNC), listens to wind, mechanical, and tire noises, and then boosts the sound level only at the problem frequencies. This masks those noises without dramatically increasing the overall sound level. The result is music and voice that sounds more natural and a system that can be listened to at lower average volume levels.

This technology is based on new DSP (digital signal processing) software developed for Blaupunkt's exclusive DigiCeiver platform. DigiCeiver is the only car audio system that performs all its key radio frequency and audio frequency operations in the digital domain. All other car radios, even so-called "digital radios," primarily use analog circuits for audio signal processing and control. Thanks to this new audio DSP software, DigiCeiver can go beyond this and produce a true digital radio which evaluate, control and manipulate sound to a degree unimaginable up to this point.

Correcting for a car¹s acoustics is not new. Until now, however, engineers needed to measure each different car model in order to determine the acoustic corrections that were needed. Then they had to build separate factory-installed systems for each different car model and sometimes for different styles within a line. This approach is used by General Motors for its premium Delco/Bose sound systems.

Blaupunkt has found a better way to accomplish the same thing, and to do so on any car. DSA uses a microphone and digital spectrum analyzer to measure the acoustic characteristics of the car, as heard at the driver's ears. Once this is done, a digital signal processor (DSP) generates a corrective equalization curve. When the correction is added to the original audio signal, the result is an essentially flat response heard by the driver. This allows individuals and car makers to achieve these highly-desirable acoustic corrections for much lower costs and without the long development times.

Once the car¹s acoustics are properly set up, the microphone teams up with the Dynamic Noise Covering system. Now, the microphone listens continuously for non-transitory road noise, wind noise, and mechanical noises such as heat and air conditioning blowers. Such noises are usually concentrated in fairly narrow frequency bands, where they can drown out music and voices at those same frequencies. In order to overpower the noise with a conventional car stereo, it is necessary to raise the volume at all frequencies. Blaupunkt¹s DNC circuit, on the other hand, removes the need to do this and instead identifies the frequency spectrum of the noise and boosts the volume only at those frequencies. This makes music, and especially voices, much more intelligible at lower volume control settings.

These remarkable new circuits will first be included in the Blaupunkt San Francisco CD70 CD receiver, which will be available in January with a suggested retail price of $699.

Blaupunkt, the mobile electronics division of The Robert Bosch Corporation, designs and manufactures high quality and high performance car audio and navigation products for sale worldwide. For Blaupunkt dealer locations and product information, call 1(800) 950-BLAU [2528] or visit the company's web site at www.blaupunkt.com.