What Sound Does a Car Make?

What sound does a cow make? That question should not stump you. What sound does a car make? That question is more difficult. For example, Vroom Vroom, or Hmmmm? Or maybe, Ta-Da! Increasingly, the sound a car makes is entirely up to the automaker, and you.

Alert readers will recall that I recently described the plethora of speakers (in this case, a plethora is defined as 30) in the new BMW iX crossover. Other alert readers alerted me to the fact that I missed the obviously interesting factoid that this electric vehicle has an unusual soundtrack. In particular, it features the handiwork of Hans Zimmer.

This vehicle's vast array of speakers can transduce any number of sounds ranging from your favorite music (K-pop) to play-by-play of your favorite baseball team (St. Louis Cardinals). It can also reproduce the sound the vehicle makes. In an electric vehicle (EV) such as this, lacking the sounds of an internal combustion engine (ICE), the sound is entirely arbitrary. To whip up something a little different, and perhaps even invigorating, BMW commissioned German composer Hans Zimmer, widely known for his film scores, to help create the vehicle's sounds.

Zimmer, in collaboration with Renzo Vitale, an acoustic engineer and sound designer at the BMW Group, synthesized a soundtrack called Iconic Sounds Electric. As with an ICE vehicle, the sounds change according to the vehicle's dynamics. You start off with a sort of whirring that surges as you accelerate, topping off with - what else - a polyphonic power chord. This happens in Sport mode; in other modes when presumably you just want to get to work on time, the soundtrack is silent.

Here is an example of an acceleration sound composed by Zimmer and Vitale. Of course, while driving, the sound is continually modulated by your speed. and acceleration.

Incidentally, in Europe, when traveling below 20 kph (that's 12 mph to normal people), the car emits an exterior noise to alert pedestrians that an otherwise nearly silent vehicle is approaching. This follows EU regulation. When ICE vehicles were first introduced, some localities mandated that a man with a flag had to walk ahead of the vehicle to warn people. I suppose the EU legislation isn't quite a comical.

According to Zimmer, “I have always been a BMW enthusiast. As a kid I used to recognize my mother coming home by the sound of her BMW. I am thrilled to get the chance to design the sound of future electric BMW’s and create emotion for the future electric driving experience. When the driver interacts with the accelerator pedal it is not only a mechanical touchpoint but also a performative element. Accelerating becomes an experience during which the driver moves through a series of gradually morphing sound textures.”

As EVs proliferate it will be interesting to see what sounds become typical for them, or if they become individualistic according to brands and models. Or maybe their sound will evolve over time as carmakers introduce new sound concepts. Should be interesting, and pretty cool. As long as they don't go Moo.

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