Continental has developed a speaker-less car audio system. The idea is inspired by the functional principle of string instruments, such as the violin. Using actuators to vibrate certain surfaces in the body of the vehicle, like a body of an instrument, they are able to amplify and generate sound.
Continental calls it ‘Ac2ated Sound‘, and experts have given this system top scores for its performance.
Car manufacturers are looking for innovative solutions to drastically reduce the weight of their vehicles and gain space for passengers and new technologies. On the other hand, design and sound quality can not suffer from this goal. Continental’s approach is to treat the car itself as an instrument.
In direct comparison to a conventional high-end vehicle audio system, a speaker-less solution can reduce the system volume significantly, while bringing down the system weight to a fraction of a typical loudspeaker solution. This invisible car audio technology can be integrated into any car model from high end sedans to small electric vehicles.
Regardless of the vehicle segment, drivers’ expectations towards car audio systems are usually very high. This is the reason why current audio systems typically require many speakers to deliver 3D sound via many channels.
The placement of tweeters (high frequency speakers), midrange speakers and subwoofers (which together make a conventional high-end car audio system) frequently interrupts the original interior surfaces with the typical look of a speaker grille. This Ac2ated Sound solution would have no visible speakers, and would allow for a simplified design of the interior.
Additionally, it is not necessary to integrate speakers with oscillating membranes when you have all the surfaces you need to do the job in the car already. The rationale behind this invisible audio system is to avoid that kind of duplication and utilize existing components for even better results.
The sound waves are generated by compact actuators, which are 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 a current speaker, larger existing components and surfaces in the vehicle are excited by the transducers to radiate the sound.
Specific areas in the vehicle lend themselves to each of the required three main frequency ranges. 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, they use large components such as the roof lining or rear shelf to generate low frequencies.
To achieve a good 3D sound, conventional high-end car audio systems can easily require ten to 20 or more speakers. Using a conventional speaker design this gives the system a weight of up to 35 lbs and a total box volume of 1 to 3 cubic-ft. Continental’s speaker-less audio system can weigh as little as 2 lbs and requires as little as .04 cubic feet of total box volume.
The system is also scaleable. Starting with the entry-level low-cost system using three audio channels, then stepping up quality is a mid system using four to six channels and the premium solution would use up to 12 channels and even the front seats are then used as sound bodies to intensify the bass 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 an indicator sound, generating the sound where the driver’s attention should ideally be.