Some years ago, sound designer Rudolf Halbmeir found himself faced with the same dilemma that the makers of the first Star Wars movie encountered when inventing the Lightsaber. He had to find a sound for something that is noiseless per se: the e-car that glides effortlessly through the streets. This happened because for humans, an environment determined by moving and shaking is of fundamental importance. With the shift from combustion to the electric engine, individual mobility is about to change. The more existential effects of the change from oil-driven to electricity-dependent are commonly debated. Yet this is also a big deal when it comes to everyday aesthetics. Twenty years from now, the streets around us will emanate a totally different sound. As electric cars don’t produce any characteristic noises of their own, sound designers foresee great opportunities—and exactly this lies at the core of future mobility aesthetics.
The sound of transition
“If you take for granted that other road users must hear a car, than we are obliged to design its sound,“ Rudolf Halbmeir says. Aged 40, Mr Halbmeir is the head of acoustic engineering at Audi in Ingolstadt, Germany. Several years of research have led him to a sound that indicates that we are in an early stage in the transition of car engines. While there may be limitless sound possibilities for a new kind of motor, there is still the force of habit. So, whether you hear an electric Tesla or a Toyota or an Audi R8 e-tron, the engine sound is still rebuilt from the legacy of the combustion engine.
“With the electric engine, you have to rebuild all the frequencies of the acoustic pattern: you need low frequencies to sound fair and powerful; you need the high frequencies to demonstrate presence. You need to show the traffic participants where the vehicle is at this very moment,“ Halbmeir explains. In a complex process, he is using about ten different software programs to transfer the audio data to the car computer. The commonly used Cubase music software forms his starting point. Not being fond of the work-intensive post-production process, he already produces a highly differentiated file within that program containing synthesizer and instrument sounds, and field recordings. The effort has to take into account the variety of driving situations. For example, when a driver accelerates the car, the sound has to react to the movement accordingly. However “a car“, says Rudolf Halbmeir, “resonates clang and vibration. If I only perceive the pure event of acceleration, then the notion of speed is reduced.”
© AUDI AG
The need for noisy electric engines is also a question of safety as well as driving quality. Mr Halbmeir continues, “From the Cubase software we translate the sounds into the industrial standard software Artemis. At the end, a machine language programs our control device.” After the programming part, the audio design further extends to means that resonate the sound to the environment. As sound is an option here and no physical fact, it has to be amplified by a system made of loudspeakers at the bottom and vibration channels throughout the inside of the vehicle. Thus the wish of some people for quiet traffic and less noise-polluted streets may be postponed.
The sound of possibility
Marek Simko, designer at Porsche Design, welcomes the new design possibilities in the age of the electric engine. “This leads to the production of light vehicles, and light vehicles may well lead to a more dynamic car design,” Simko says. As motors running on electricity lack all transmission parts, designers see a new freedom. Even the great weight of the battery, 300 kg or more, is the starting point for a quest for new materials that are lighter than the ones used before. For example, the i3, a concept e-car by BMW slated for serial production in 2013, is made of carbon fiber—a material that used to be common only in racing cars and high-end bikes. Furthermore, peak oil prices and a rising awareness for environmental issues increase the competition therefore Marek Simko sees a great potential in electric engines. He says, “The automobile was invented as an electric engine car. Yet when the combustion engine was invented, technology changed. That is why electromobility is faced with the same challenges as Ferdinand Porsche, who proposed a wheel-hub machine which was later presented as the Lohner-Porsche in 1900.”
But don’t forget about the constraints. There are special laws concerning car sounds in various regions of the world. While experts in Japan are already discussing whether it may be fruitful to mimic nature sounds, such as bird’s voices, rather than the good ol’ roaring of combustion cars, Mr Simko sees quite different potential: “There is a lack of new car types. I wish for a yacht that could sail on four wheels—a vehicle to mediate a slowed-down driving experience.” Setting sail in the urban traffic flow!