Continental's Advanced Car Audio System Uses No Speakers

author: Eric Walz   

In the era of connected cars and streaming music services, the CD player, is no longer a must have option for car buyers, as passengers can simply stream the music they want to hear on demand.

In addition, automakers are finding ways to build cars that weigh much less. For example, many automakers have eliminated the heavy spare tire and Mazda just announced it will replace the heavy lead-based starter battery on some models with a compact, lightweight lithium-ion one.

Inside the car, the global automotive supplier Continental is reinventing the traditional car audio system. According to a New York Times report, the company has developed a new audio system that does not require a traditional speaker. The sound waves in Continental's audio system are generated by compact actuators, which are similar to the core of a conventional speaker.

For audiophiles, deep bass, rich midrange and crystalline highs of their favorite music will still be there. It will just be coming from the car itself instead of speakers. Continental installed the system in a late model Mercedes Benz C-Class to demonstrate its speakerless audio system. Continental says the solution delivers excellent acoustics – even to the most discerning ear.

The new car audio system, which Continental calls ‘Ac2ated Sound' replaces conventional audio speakers with tiny actuators—which are really like tiny transducers, and create sound by vibrating certain surfaces in the vehicle. Continental says its invisible car audio technology can be integrated into any car model from high end sedans to small electric vehicles.

At considerably lower weight, with dramatically reduced volume and lower electricity consumption, In direct comparison to a conventional high-end vehicle audio system a speaker-less solution can reduce the system volume by a factor of ten or higher, while bringing down the system weight to a fraction of a speaker solution.

Design Challenges to Integrate Speakers

The mix 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 front. Car designers must find ways to place all of these speakers throughout a car's interior. This incurs extra design costs, as well as extra weight.

With Ac2ated Sound, it is not necessary to integrate speakers with oscillating membranes as the surfaces that are needed to do the job are available in the car already. The rationale behind this invisible audio system is to utilize existing components for even better results.

These actuators consist of a magnet and a coil, which generate micro-vibrations. However, instead of an oscillating membrane which is part of a typical speaker, larger existing components and interior surfaces, such as door panels, inside the vehicle are excited by the transducers to radiate the sound.

Continental's engineers found that specific areas inside the vehicle lend themselves to each of the required three main frequency ranges for any audio system. While the A-pillar is suited for high frequencies, the door panels, for instance, have the right properties for generating medium frequencies. Similar to standard speaker technology, large components such as the roof lining or rear shelf are used to generate low frequencies for bass.

When a transducer is placed in a door panel, the sound waves from it are transferred to the surrounding door panel using a special bonding technique.

To achieve high-fidelity 3D sound, a conventional high-end car audio system can easily require between ten and 20 or more speakers placed throughout the vehicle's interior space. Using a conventional speaker setup, the system can weigh up to 15 kilograms, with a total box volume of ten to 30 liters.

For comparison,Continental's speaker-less audio system can weigh as little as 1 kilogram and requires as little as 1 liter of total box volume.

For automakers, a speaker-less solution such as the Ac2ated Sound can reduce the system volume by a factor of ten or higher, while bringing down the system weight to a fraction of a traditional speaker solution.

Eric Walz

Originally hailing from New Jersey, Eric is a automotive & technology reporter covering the high-tech industry here in Silicon Valley. He has over 15 years of automotive experience and a bachelors degree in computer science. These skills, combined with technical writing and news reporting, allows him to fully understand and identify new and innovative technologies in the auto industry and beyond. He has worked at Uber on self-driving cars and as a technical writer, helping people to understand and work with technology.