Speaker-less audio system saves weight, volume
In comparison to conventional audio technology, Continental claims that its speaker-less system has many advantages such as lower weight, dramatically reduced box volume and lower power consumption. Plus, it is easier to integrate into the vehicle than the multiple speakers required for today’s rather sophisticated 3D sound systems.
The sound waves are generated by compact actuators similar to the core of a conventional speaker. These transducers consist of a magnet and a coil, which generate micro-vibrations. However, instead of an oscillating membrane which is part of current speakers, larger existing components and surfaces in the vehicle are excited by the transducers to radiate the sound. “If you take a violin for comparison, the bow and strings are the transducer. The violin’s bridge equals the location and bonding of the transducer to the surface which equals the instrument body”, said Dimitrios Patsouras, director competence center NVH (noise, hibration, harshness) at Continental Engineering Services. Specific areas in the vehicle lend themselves to each of the required three main frequency ranges – tweeters, midrange speakers and subwoofers. “The A-pillar is suited for high frequencies, while the door panels, for instance, have the right properties for generating medium frequencies. Similar to speaker technology, we use large components such as the roof lining or rear shelf to generate low frequencies”, Patsouras explained. To achieve a good 3D sound, conventional high-end car audio systems can easily require between ten and 20 or more speakers. Owing to a conventional speaker design this gives the system a weight of up to 15 kilograms and a total box volume of 10 to 30 liters. Continental’s speaker-less audio system can weigh as little as 1 kilogram and requires just 1 liter of total box volume.
In a demo vehicle, Continental is presenting the scalability of the system by switching between an entry-level low-cost system using three audio channels, a mid system using four to six channels and even a premium solution using up to 12 channels. Thereby, even the front seats are used as sound bodies to intensify the bass experience and to provide passengers on the rear seats with a new audio experience.
Speaker-less technology offers further potential beyond car audio: It can also provide a sound source for human-machine interaction concepts, such as navigation instructions or the indicator sound.
The company said it will demonstrate the speaker-less system along with its multimedia products during the IAA International Motor Show in Frankfurt (Germany).