The Soundtrack to an Electric Car

When General Maximus — that’s Russell Crowe in “Gladiator” — leads his Roman legions into battle, Hans Zimmer’s bombastic, percussive score propels them to victory.

As hundreds of bedraggled British troops waging World War II await a tenuous evacuation from the beaches of “Dunkirk,” Mr. Zimmer’s tick-tock effects mirror their anxiety and urgency.

As the 1976 Formula One championship roils toward a climax in “Rush,” Mr. Zimmer’s synthesizer is there on the rain-soaked track in Japan, fueling the fight.

And when a driver starts up his or her electric-powered BMW i4 sedan later this year or next, Hans Zimmer will be riding shotgun, so to speak, creating a sonic signature for the car, because electric motors make little sound.

“I can sum it up, from Day 1 to now: It’s never finished, it’s always an experiment,” Mr. Zimmer said recently in a phone interview from London. “We’ve been trying to create sounds which are aesthetically pleasing and calming — sort of anti-road rage.”

So don’t expect to hear the growl of an overtuned V-8, the bark of an amplified exhaust, the screech of tires digging for grip. Mr. Zimmer wants to take you to a different place. “It’s something that transports you in the most elegant way possible,” he said. “We are trying to make your life less chaotic, more beautiful.”

But beyond aesthetics and marketing, enhancing an electric car with sounds is a legal issue as well. In the United States, the National Highway Traffic Safety Administration adopted rules in 2018 that say electric cars must make some artificial sounds. Congress made it a requirement that light-duty hybrids and electrics emit noise as a safety measure for pedestrians, bicyclists and people with a visual impairment.

The European Parliament has mandated that electrics sold in Europe will have to “sound similar” to cars with combustion engines at speeds below 20 kilometers an hour. The rule is to take full effect in 2021.

So far, BMW is alone is hiring a composer with Mr. Zimmer’s repertoire, and this work is a labor of love for the 62-year-old, German-born musician. He said the Bavarians “came to me” to accept the work, “although a half-hour later I had an email from another company to create something for an electric car.”

“But I grew up with BMW. My family always drove BMWs,” he added. “There was an emotional connection there.”

Certainly, the German carmaker isn’t alone is seeking ways to fill in the sonic voids that are inherent in electric cars. Mercedes-Benz and Volkswagen have assigned development teams to work toward similar ends for their electrics, as have Jaguar, Nissan, General Motors and others.

“The electric vehicle sound is its identity,” Frank Welsch, responsible for technical development at Volkswagen, told Reuters last year. “It cannot be too intrusive or annoying. It has to be futuristic, and it cannot sound like anything we had in the past.”

BMW’s soundtrack is very much a work in progress for Mr. Zimmer and his partner in the project, Renzo Vitale, the automaker’s sound designer. Mr. Zimmer, who maintains an exotic sound laboratory in Santa Monica, Calif., is fitting it in between his film work: He was putting the finishing touches on his score for the new James Bond movie, “No Time to Die,” (which has been delayed until November) when we spoke in mid-March.

He explained that, in his view, the “BMW IconicSounds Electric” commission was more about deleting than adding. “Too much information would automatically be distracting,” he said. “If you look at the great pieces of art, it’s usually the simplicity that makes them great.”

Mr. Zimmer was asked if the rather chaotic soundtrack he created for “Rush” might somehow translate to excite the experience of an electric car, much the way a loud, vibrating exhaust might affect a driver’s senses.

“‘Rush’ is not about your normal day of enjoying your car,” he said. “We’re not building racecars here. We’re taking you on a different journey.”

BMW Concept i4 Sport Sound

Some of the created sounds released so far by BMW have been described in rather esoteric terms. One white paper from the company calls out a “liminal threshold” with sound that is “manifold” and “chameleonic” with “presence that is subtle but unavoidable.” Among the tones to reach the listeners’ ears are those with mid- to high frequencies, low frequencies and a “dynamic pulse train” that provides a “throbbing sensation.”

Mr. Zimmer, who doesn’t try to describe these “compositions” in sentences (he is the first to allow that it’s nearly impossible to describe music with words), has a somewhat more ethereal view.

“A car can be the most beautiful form of solitude, yet there’s the companionship you get from the engine,” he said. “Part of what we’re trying to do is to create sounds which are aesthetically rather pleasing and calming.”

At the same time, said Mr. Vitale, the sounds that may be used to identify the car’s start/stop systems, for example, are “intended to instill a sense of excitement.”

As for the composer, “I’m still trying to get closer to the truth,” Mr. Zimmer said. “How am I going to connect the humans to the machine? How am I going to give you the freedom in this world I create to be an individual and tell your own story?”

He sighed, then said, “Our rubbish bins are full of dead sounds, things which seemed hopeful and exciting and then turned out to be going in the wrong direction.”