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Electrifying sound

Audi sound engineers Rudolf Halbmeir and Stephan Gsell developed the Audi e-tron® GT quattro® model’s sound. Here’s a peek behind the scenes to explore the creative process, sources of inspiration, and challenges.

Text: AUDI AG Photo: AUDI AG Reading Time: 5 min

Soundwave e-SoundSoundwave e-Sound

Sound is an integral part of our lives and takes many different forms. It can spark emotions and prompt memories. It could be a gentle rustling of the wind in the treetops, a city’s lively hustle and bustle, rain against a window pane, or a crowd’s furious applause in a stadium. Whatever the sound, it’s always a unique and identifying feature. This is especially true at Audi.

The sound of our mobility is undergoing a sea change

As sound engineers at Audi, Rudolf Halbmeir and Stephan Gsell have a great deal of experience. Halbmeir has been designing vehicle sounds for almost 20 years, and, with the shift to electric mobility, the nature of his work has changed. “In my first nine years at Audi,” Halbmeir explains, “I mainly focused on making cars with combustion engines quieter. Then my supervisor at the time asked me if I would be interested in creating sounds for electrically powered models.” When Stephan Gsell joined the team five years ago, he, too, was tasked with making vehicles quieter—until the first Audi hybrid model came along and changed the game.

Today, the pair are responsible for giving the Audi e-tron® models their sonic signature. This entails taking not only legal requirements into account, but also each car’s unique character. No easy task. “Meeting many demands is a tricky balancing act,” says Halbmeir. “Of course, it’s important that the sound is easy on the ear. Even the coolest options might not be a good fit with the vehicle in question.” In seeking the ideal Audi audio, inspiration can come from anywhere and everywhere.

A car’s sound is a lot like music. Along with a thematic tune, it needs a kind of hook.

Rudolf Halbmeir

Audi sound engineer Rudolf HalbmeirAudi sound engineer Rudolf Halbmeir

Even everyday objects can be sources of inspiration.

“A car’s sound is a lot like music,” muses Halbmeir. “Along with a thematic tune, it needs a kind of hook—a catchy, instantly recognizable melody. In my search for the Audi e-tron GT quattro model’s signature sound, I left no stone unturned, trying everything from violin through electric guitar to the Australian didgeridoo. But none of it felt right. So I started experimenting with everyday objects and finally got what I was looking for: I put a fan in front of the opening at one end of a tube and listened to what came out the other end. It was a very special, deep ‘thrumming’. I knew instantly that I had my basic note.”

Hitting on a basic note is a crucial first step in developing a car’s sound, but it’s not the end of the story. You also need gradations: Low frequencies evoke self-assured strength, medium ones express sportiness and agility. High frequencies, in turn, lend a certain sparkle and are a good fit with an electric car’s electro-soundscape.

Purpose-designed software for developing the Audi e-tron models’ sound.

To hash out the finer details, the sound engineers put their skills to work in the Audi sound lab as well as with computers in the office. One of their tools was a purpose-designed program with parallels to commercial software for creating music. “When we started developing the sound for the Audi electric models, there was unfortunately no commercial software on the market that filled the bill. So instead of sitting on our hands, we programmed our own,” explains Stephan Gsell.

With the help of this technical tool, Halbmeir and Gsell kept refining the frequency structure. In the end, the result was a highly polished sample of 32 tones, running the gamut from post-edited synthesizer sounds and noises that resemble a cordless screwdriver to recordings of a model helicopter, among others. Of course, the tube not only made it into the repertoire, it was incorporated into the selected variations of the theme.

“Thanks to the algorithm that variously mixes and weighs individual tones, our sound is always being created afresh. Despite certain parallels with musical compositions, there are also differences, such as the lack of a discernible beginning, middle, and end,” adds Gsell. “Instead, it’s run-on audio. The Audi e-tron GT quattro has to sound good in every driving situation. More than that, it has to be powerful and fascinating.”

Thanks to the algorithm that variously mixes and weighs individual tones, our sound is always being created afresh.

Stephan Gsell

Audi sound engineer Stephan GsellAudi sound engineer Stephan Gsell

While in Efficiency mode, the vehicle is limited to the AVAS warning sound. But shift to Comfort mode and the rear exterior speaker comes into play, making the exterior sound even fuller. This symphony accompanies the car beyond the 200-kilometre-per-hour mark. In Dynamic mode, the exterior sound is amped up and rounded out with an interior accompaniment. This means the Audi e-tron GT quattro is the brand’s first EV in which individuals can choose their vehicle’s tune—whether it’s the quiet hum of the electric motor or a powerful soundscape. After all, it’s not just sound that has many facets. So do the Four Rings’ individualization options.

Components of the exterior sound Components of the exterior sound
Components of the interior soundComponents of the interior sound