Bob Maddox’s stage name, Crazy Rocketman, is a misnomer. Maddox doesn’t build rockets. He builds pulse-jet engines. There’s a difference. As for the crazy part—that may be true. Maddox is the world’s ...

When the Mercedes EQS electric sedan hits the street sometime later this year, drivers will be able to choose between three “soundscapes”—digitally produced noises pumped out of the speakers meant to ...