As premium audio systems have become common in mainstream cars, the number of speakers in vehicles has increased. But along with this improved sound comes added weight, and more space is needed to house the speakers.
Recently I got a chance to see and hear a new cutting-edge sound system by automotive supplier Continental called Ac2ated Sound that reduces weight and saves space by eliminating traditional speakers altogether. Instead the Continental concept audio system uses compact actuators to “excite” parts of the interior such as the dashboard, doors and ceiling to create sound.
The actuators are similar to conventional speakers in that they contain a magnet and a coil that pulse in relation to the frequencies they’re fed by an audio source such as radio. But instead of moving a membrane made of paper or some other material, the system uses the resonant property of interior materials to create the sound.
“The A pillars, the dashboard, the ceiling and the back covers of the seat produce the sound,” pointed out Jens Friedrich, an acoustic engineer with Continental Engineering Services, who demoed the system for me. “Every surface has its own acoustic behavior,” he added.
“If I knock here, for example,” Friedrich said while tapping the dashboard, “it produces a sound. If I knock here,” he said while rapping the A pillar, “it produces a different sound.”
The A pillars, Friedrich said, are ideal for reproducing mid to high frequencies. “The ceiling, since it’s a large surface, is capable of low frequencies,” he added. “We use the modal structure of the interior component and by combining these different frequency ranges we can achieve a very good sound experience.”
Friedrich said that the weight advantage of the speakerless audio system is a significant benefit for electric vehicles. “Electric vehicles are pretty heavy due to the battery,” he notes. “Automakers ask us to reduce weight on every other component, and with this technology we can provide a big weight savings.”
Conventional speakers also take up valuable space in a vehicle. “We have the potential to reduce the volume that’s needed to integrate a sound system in the car by up to 90 percent,” Friedrich said. “There are so many new modules for connectivity and other technology, and OEMs need to package them somehow,” he added. “We help them make space.”
The Ac2ated Sound system also changes the interior design potential for cars. “The mix of tweeters, 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,” Continental said in a statement on the new concept. “Designers do not always welcome this.”
Friedrich remarked that in emerging markets entry-level car buyers don’t focus as much on good sound. “They mostly listen to radio and that’s enough,” he said. “So the solutions have to be light and cheap. We can provide a good acoustical experience with fewer parts.”
He added that the speakerless system can also be enhanced for luxury cars, like the Mercedes-Benz sedan that was used for the demo. “Some people spend a lot of money to get a great sound system,” Friedrich said. “Our technology can also satisfy those customers.”
So how did it sound? Pretty impressive, based on a short demo with a variety of music. Overall tonal quality and stereo separation were impressive, although the bass sounded a bit muddy. The sound also had an enveloping quality since its wasn’t localized at speakers.
“You want sound coming from everywhere if you want to have a surround sound experience,” Friedrich said. “We achieve this by using the surfaces of the car.”
Originally published by Forbes.com