Creating the Soundtrack for Vehicle Electrification

Driving has always been a multisensory experience—from the design to the look and feel of cabin materials to seat comfort. That will remain an elemental part of the experience as we transition from internal combustion to electric propulsion. But one component that is going away is the sound of an engine. Although many drivers won’t mind losing engine noise, those of us with more enthusiasm for driving definitely will. Automakers understand this, and most are developing new and unique soundtracks specifically for EVs. 

Issues with Reduced Noise

The sound created in engines as the combination of intake and exhaust pulses to the thousands of mechanical bits that slide and rotate to make torque can be a very visceral experience. When I first drove a Tesla Roadster through the mountains above Silicon Valley in early 2008, I came away impressed by the instant thrust provided by the electric motor with only a single moving part and the amazing handling of the Lotus-derived chassis. But the only sounds were the tires scrambling for traction around corners and the wind rushing through my hair.

When Ford revealed the Mustang Mach-E in November 2019, Mustang fans were outraged at the idea of a vehicle with the iconic pony badge that didn’t have the sound of a rumbling V8 engine. BMW is renowned for the precision mechanical sound of its inline six-cylinder engines, and there is nothing quite like the sound of a Ferrari. 

Drivers aren’t the only people that experience the sound of cars. Walking the streets of Manhattan a couple years ago, I pondered how the experience would change when the hundreds of thousands of cars and trucks were electric. Some people just don’t like what they consider noise pollution, but those with low vision often rely on sound cues to know when it is safe to cross a street. 

Let’s Make Some Noise

As automakers prepare new EVs, they are considering what sort of soundtrack is appropriate for each model and driving mode. Drivers of Ford’s Mach-E can choose from Whisper, Engage, and Unbridled modes. As expected, Whisper provides a near silent experience when moving down the road. Since any sound from an EV comes from the audio system, it can be programmed to sound like anything. Ford sound designers opted for Unbridled mode to have a low rumble that comes across as the distant echo of classic Mustangs but is synthesized and authentic to the EV experience. 

BMW hired composer Hans Zimmer, who has scored more than 100 films, to create specific tones for its new lineup of EVs. “The first thing we did was to try to translate, in sound, what is the feeling of an explosion related to sound,” said Renzo Vitale, creative director of sound at BMW. 

Zimmer queried, “How can we give something that is even more of an experience than they had with their petrol engines and make it more exciting and more joyful to drive?” The result is a multi-textured synthesis that is tied directly to the way the car is behaving. 

Renault is collaborating with the Institute for Research and Coordination in Acoustics/Music (Ircam) in Paris to create its EV soundscape. Renault and Ircam are studying a wide range of synthetic and natural sounds from different materials and instruments. 

The future sound of cities and roads will be different from what it has been for the past century. It will likely be much quieter than today but not entirely silent. The big question is: With so many companies approaching the problem, will it be a mild cacophony or a harmonious symphony?