“You can’t tell where it’s coming from,” Mr. Haefele shouted.

Switching to Marvin Gaye’s classic “Heard It Through the Grapevine,” he pointed to the A-pillars. Tambourine and guitar riffs rang out crisply as Mr. Gaye crooned about the anguish of his betrayal.

The system, which Continental calls Ac2ated Sound, should begin appearing by 2021, Mr. Haefele said. He declined to name the carmakers that will offer it, although Mercedes, BMW and Audi are all big customers — and frequent adopters — of Continental’s technology.

The company envisions creating a basic sound system with five transducers, a midprice system with eight and a high-end system with 10. Continental also sees the system providing a new way of selling and upgrading in-car audio, Mr. Haefele said. Carmakers could build all their models with 10 transducers, and turn on only those the customer paid for. The owner could later buy an upgrade that would power up additional transducers and turn a basic audio system into a premium version.

But such integration of the sound system into a car’s interior does present some complications.

In the case of an accident, a damaged A-pillar or windshield would have to be replaced to restore sound quality, Mr. Haefele said. “But this is very similar to conventional speaker systems where the speakers are integrated into the A-pillars,” he said. Something like a chipped or nicked windshield should not affect audio quality, he said.

James Grace, a senior director at Cox Automotive who previously worked in automotive interiors, said the biggest challenge for developing speakerless audio systems would probably be eliminating the vibrations, hums and rattles that so often emanate from interior parts, and properly integrating the sound-producing parts with the rest of the car.

“Interior parts are not typically made to produce high-quality audio,” he said, but added that it was a “pretty clever idea.”