That vroom-vroom … is it real or digital?

COLUMBUS, Ind. -- Andrew Pontius, Faurecia’s chief exhaust engineer, sat in the front seat of a BMW 328i sedan. With his finger on an iPad touchscreen and one foot on the accelerator pedal, he showed me how exhaust sounds will be generated in the future. 

Pontius revved the Beemer’s 2.0-liter, four-cylinder engine. With a touch of the iPad screen, the engine emitted the sensual moan of a V-6 Maserati. 

With another touch, I heard the throaty roar of a BMW M3 V-8. Next, the V-8 muscle car growl of a 2014 Ford Mustang 5.0-liter V-8.

With a final touch, the engine quieted to a gentle thrum, especially useful for freeway cruising.

The next day, I told an automotive purist friend about Faurecia’s technology and got an unexpectedly visceral reaction. 

“I would NEVER buy a car with that,” he sniffed.

The sound of a car’s exhaust is its sonic signature, especially for sporty cars. People have been tinkering with exhausts forever. In high school, I remember hot rodders using glass packs to put vroom in their mufflers.

But there’s something about outright digitally manufactured sound that crosses a line in the sand for those who like their tailpipes to sound pure and natural.

My friend’s reaction shows why carmakers face a tricky dilemma employing such technology. 

Fuel economy regulations and customer demand for efficiency are driving car companies to wring more horsepower out of smaller engines using turbochargers, cylinder deactivation, engine down-speeding, multispeed transmissions and so on.

All these may be good for the planet, but not great for car lovers who expect a roar, rumble, growl or throaty moan when they step on the gas.

“The way powertrains are going, they aren’t going to make a lot of noise any more,” says Pontius. Powertrains of the future tend to give off very low-frequency sounds, “the kind of drone that makes you wish you were deaf driving down the expressway.”

Asked to describe the sound more precisely, Pontius chooses his words carefully: “an agricultural sound.”

You mean like a tractor?

“Yup,” he says.

And nobody wants a sporty car like a Ford Mustang or BMW 328i to sound like an old John Deere.

Carmakers and suppliers are already using software and active noise cancellation to alter the sound inside vehicles using the vehicle’s amplifiers and speakers.

The next phase, Pontius explains, is generating exhaust sounds digitally to alter the sound of the exhaust sound outside the car.  

Faurecia wants to do it with a combination of active noise cancellation to mask the tractor tones and digital generation of the kinds of alluring tones motorists expect. The system, called exhaust dynamic sound generation, uses an amplifier and speaker adjacent to the exhaust system. Faurecia is talking to several customers, but the system is not in production yet.

“We could make a four-cylinder turbo sound like a two cylinder Harley and you can create the blub-blub sound from a dual tailpipe engine,” even though the real engine only has a single tailpipe, he says. The sky is the limit.

Pontius believes such systems are inevitable in the near to medium term.

“Within the next five years, I see quite a few more vehicles having sound generation,” says Pontius. “Starting about 3-5 years from now, we’ll see our first production of noise cancellation and sound generation, initially offered as options on higher trim levels. Once you get people excited about the technology on high-end models, the take rate will go up. Once it becomes standard on high-end models, it will filter down” to the mass market.

He estimates costs could drop from a few hundred dollars now to under $100.

But it will all come back to that thorny issue of consumer acceptance. 

“People need to understand they’re either going to get a hairdryer sound or something synthetic,” said Pontius, “… if they can open their minds to getting something better that’s synthetic.”