Engine sounds enchant car enthusiasts. Yet even without an engine, BEVs can still use sound to delight drivers. We look at sound creation in the age of electrification.
So far in this series, we have explained various types of engine sounds—that is, those made by cars with reciprocating engines.
But what about the sound of Toyota’s electric vehicles? Whether powered by fuel cells (FCEVs) or batteries (BEVs), they too are not silent, producing a unique whirr or whine as they drive.
At a company induction ceremony during his term as president, Akio Toyoda had a Supra set up on stage so that the new employees could hear the sound of its engine.
Akio Toyoda (then president)
I want to make sure this ceremony stays with you for the rest of your lives.
The sound of an engine, in the age of electrification… It's not a race car; it’s a bit more polished.
I believe cars are to be experienced with all the senses. As we forge ahead in the CASE era, let's work together to show everyone how fun cars can be, and deliver Mobility for All!
As Akio put it, cars are to be experienced with all five senses.
No matter how fast a car takes off when you step on the gas, would you still get a true sense of that acceleration without the accompanying sound of climbing revs?
Electric vehicles are no different, and they too should be experienced with all the senses. For this article, we looked at how sound is created in cars without engines.
The right sound for the car
Through our previous interviews with Toyota’s engineers, we learned that a car’s sound design should correspond to the driving power of that particular vehicle.
For instance, some readers may remember those “Huh?!” moments in old cartoons when a supercar that looks like it should pack a mighty roar is given sound effects that resemble a motorbike at best. To those who love engine sounds, the idea that audio must match the visuals probably seems obvious.
How, then, do you design sounds for a car powered by something other than an engine? We posed the question to Shinichi Sano, assistant manager of Vehicle Performance Development Department No.1, Lexus Vehicle Performance Development Division. Since the 2010s, Sano has worked on sound design for models including the Mirai (FCEV) and BEVs such as the Lexus UX300e.
Assistant Manager Sano
When I worked on the Mirai and UX300e, the first image I came up with for the sound was Fujin (the wind god) and Raijin (the thunder god).
The Mirai, which takes in air and creates electricity from hydrogen and oxygen, was to be the wind god, while the electric UX300e would be the thunder god. I played with the idea of making the UX300e boom and crackle like thunder when you stepped on the gas, but unfortunately, the idea was set aside after much deliberation…
The Mirai, however, retained its Fujin element, in the way it whooshes like the wind.
The sound of thunder… Since this fascinating idea, unfortunately, did not come to pass, we asked Sano what it would have sounded like.
Assistant Manager Sano
Our prototype sound was composed of random thunder-like noise, but interestingly enough it never sounded unnatural no matter how many thunder sounds we layered on top of each other. That’s why I thought it might just work.
With engine vehicles, you build up the sound with different orders (corresponding to engine speed), but as you can imagine, if you replace that with random noise, the sound doesn’t quite feel responsive when you step hard on the gas pedal.
We tried all sorts of things, such as making the sound sharper, but we just couldn’t get that responsiveness.
In the end, we put a lid on the thunder idea but kept the random noise component, adding order tones to create the final sound.
Here is an idea of how that bottled lightning might have sounded.