Emotive, genuine and innovative: the sound design for the DTM Electric car
Schaeffler has taken the next step towards the future of the DTM. The Schaeffler-developed DTM Electric once again thrilled spectators during a sound run at the DTM event at the Red Bull Ring – not only with its breathtaking driving properties, but also an emotive acoustic, the likes of which the motorsport world has never heard before. Schaeffler brand ambassador Sophia Flörsch was the first to present the future sound of motorsport at the racetrack. The design could also provide a new sound for electric cars soon.
- Schaeffler sets benchmarks with new sound design for electric cars
- Schaeffler specialists analyze the sound using sound synthesis software developed in-house
- Dr. Jochen Schröder: “Like an e-motor, but cooler.”
- Lightweight solution for motorsport
- DTM sound innovation ready for production
- Johannes Blickensdorff: “Sound is more important than ever in e-mobility”
- The emotive soundtrack for electric motorsport
Schaeffler sets benchmarks with new sound design for electric cars
The sound run for the DTM Electric, with Sophia Flörsch at the wheel, was a special event in many regards. On one hand, it demonstrated that fully-electric race cars also sound like thoroughbred race cars and are thus able to convey the emotions that make motorsport so unmistakable. On the other hand, it is the innovative technical approach taken by Schaeffler that makes the thrilling new DTM sound possible at all.
Schaeffler specialists analyze the sound using sound synthesis software developed in-house
The technology behind the sound is fascinating. Unlike other manufacturers, Schaeffler does not use classic loudspeakers or bass reflex concepts. Instead, the Schaeffler concept – the sound synthesis with the original car sound – animates the entire body and causes it to vibrate in many places. This way, the car itself becomes a form of speaker membrane, blasting the sound in all directions. Simply put, it is a similar principle to the one that gives musical instruments like the violin and bass their unmistakable sound.
To ensure that the DTM Electric sounds both authentic and modern, the sound of the electric powertrain was first analysed in detail. Software developed specifically for synthesizing sound was then used to create a new sound profile especially for the race series. As the car races around the track, vehicle data such as engine speed, engine load and brake pressure is fed into the software in real time. The software then adapts the pitch and sound level of the stored profile in sync with changes in the actual driving situation. As the driver accelerates and brakes at different speeds, a dynamic and authentic sound is generated.
Dr. Jochen Schröder: “Like an e-motor, but cooler.”
The new race car sound of the DTM Electric is modelled on the sound spectrum of the car’s electric motor – a motor made by Schaeffler. “The DTM Electric is not intended to mimic a typical combustion engine or sound like science fiction,” said Jochen Schröder. “Rather, we developed a sound that closely reflects the physics of an electric motor, but sounds even cooler.”
One unusual challenge for the Schaeffler acousticians was the fact that the race car sound should primarily be heard in its full glory by spectators, not necessarily the driver. “We tackled the issue of sound, precisely because we take feedback from experts and fans seriously,” said Johannes Blickensdorff, the leading sound designer for the DTM Electric at Schaeffler. Ultimately, the DTM Electric race series, if it takes to the grid in 2024 as planned, will not only create an emotive experience for fans and spectators due to its breathtaking battles with electric cars, but also with an unmistakable, authentic electric motorsport sound.
Lightweight solution for motorsport
Blickensdorff adds: “One particular challenge was posed by the strict space and weight constraints of just a few hundred grams for the installation in the race car, whilst still meeting the requirements of robust and maximum audibility among the spectators in the grandstands. As we are not taking an electroacoustic approach, the power consumption of our sound system is an important factor, in order to extend the life of the battery.”
Schaeffler has solved these challenges and developed a sound design for electric cars that not only authentically recreates the character of the sound of the electric car, but also meets the high demands of motorsport. It goes without saying that motorsport is not the only field in which the sound design can put its benefits, such as low weight and low energy consumption, to use.
Schaeffler brand ambassador Sophia Flörsch drove the DTM Electric during the sound run.
DTM sound innovation ready for production
“In the future, we will also offer automobile manufacturers real-time sound synthesis for electric road cars – both for brand differentiation and for creating an authentic sound for every driving situation,“ said Jochen Schröder. This means that not only will the DTM sound change, but electric cars could also sound very different soon.
In developing this technology, Schaeffler draws on more than 20 years’ experience in the field of NVH, which stands for noise, vibration and harshness. Developments in NVH are usually focused on filtering out unwanted noises from vehicle components by dampening or eliminating them altogether. Only noises that are easy on the ear should remain.
While the new sound of the DTM Electric is based on the actual sound of the car’s electric powertrain, vehicle manufacturers are more or less free to decide for themselves what their cars should sound like. “From the acoustics of traditional combustion engines to futuristic soundscapes, we can give vehicle manufacturers plenty of options,“ said Jochen Schröder. And so the road to a new sound design for electric cars has been mapped out.
Johannes Blickensdorff: “Sound is more important than ever in e-mobility”
What would motorsport be without its unmistakable sound? This is a question that is particularly relevant to fully-electric racing series. How do you combine electric cars with emotive sound? Schaeffler has the answer. The technology was given its premiere at the sound run of the DTM Electric at the Red Bull Ring. In an interview, Schaeffler’s acoustics expert, Johannes Blickensdorff, explains how the all-electric race car, which has been developed by Schaeffler, manages to convey the acoustics of motorsport in an emotive way. Schaeffler’s innovative technology does not depend on speakers, is extremely light, and could also be heard in everyday traffic in the future.
What role does sound play in automobile manufacturing for you and Schaeffler?
Johannes Blickensdorff: Together with the design and performance figures, the sound of a car is one of the main reasons for deciding to purchase a car. This is not always rational, but we all know that the emotions and degree of excitement, which are heavily influenced by the acoustic character of the car, form an important basis to this decision. This includes ensuring that there are no negative experiences of sounds in a car, or noises from individual active components, such as the transmission or actuators. If the sound in general is not in line with the brand promise, class of car or operating conditions, then this can soon become a primary reason for the end customers rejecting it completely. This also applies in motorsport. In short, the sound of a car is more important than ever in e-mobility. This subject is made all the more relevant by the lack of a combustion engine as a primary source of sound.
Is it not a contradiction to give what is actually a “quiet” electric car a throaty motorsport sound?
Blickensdorff: From an acoustician’s perspective, the far quieter powertrains obviously make e-mobility a real “blessing” – as it is for such applications as in urban traffic. The goal for us in motorsport is not to mimic a classic combustion engine, neither with regard to the power nor the impression of the sound. Rather it is to give the cars and manufacturers their own acoustic fingerprint and, in doing so, to intensify the character of the car. The components installed mean the basic sounds of electric cars differ far less from each other than many customers, and perhaps the odd marketing department, would like. Or they give rise to acoustic associations, that we are more familiar with from trains (ICE) and other uses of electric motors.
What makes the sound design of the DTM Electric so special?
Blickensdorff: In contrast to many production vehicles, which have already implemented active sound design or active noise cancellation (ANC), the focus in motorsport is not on the sound inside the car because, for example, the driver wears a helmet anyway. One particular challenge was posed by the strict space and weight constraints of just a few hundred grams for the installation in the race car, whilst still meeting the requirements of robust and maximum audibility among the spectators in the grandstands. As we are not taking an electroacoustic approach, the power consumption of our sound system is an important factor, in order to extend the life of the battery.
Can you explain, in simple terms, how the sound of the DTM Electric is achieved?
Blickensdorff: The assignment has two aspects. The first is to prepare the car in such a way that it emits the sound as effectively as possible and with little additional weight. Unlike other manufacturers, we do not use classic loudspeakers or bass reflex concepts. Instead, we animate the entire body with our car sound, causing it to vibrate in many places. This way, the car itself becomes a form of speaker membrane, blasting the sound in all directions. This saves weight and is far more robust than classic loudspeakers. The second aspect is the sound itself, which we calculate dynamically in real time, based on internal car data. A sound synthesis, which, together with the existing sound of the components installed in the car, must merge to form a sporty and believable overall impression.
What tests have you performed, in order to perfect the sound of the DTM Electric – and how do you actually test the sound of an electric car?
Blickensdorff: For a long time, the sound was one of the main criticisms. Surveys at the circuits have shown this clearly. As well as subjective feedback, the branch of “psychoacoustics”, which deals with the quantification of humans’ auditory perception, provides us with the tools required to evaluate classic measurements. However, we have also learned that the final impression can only really be assessed at the test track itself, with the right distance, Doppler effects, tyre noises, etc.
When did you know that you had found the perfect race car sound?
Blickensdorff: Like in the cinema or with a good film, a car’s acoustics and association must tie in with its performance data and sporty look, otherwise “something is missing” or it seems implausible. It is right when the sound merges into all the other properties out on the track in such a way that it neither sounds superimposed nor unsuitable. It should convey acceleration behaviour and speed ranges, while observers should be able to judge distance and when a car is entering a corner. It goes without saying that there should also be plenty of goosebumps and action…
Has the sound of the DTM Electric already been finalised, or are you still incorporating feedback from fans and motorsport experts?
Blickensdorff: We tackled the issue of sound, precisely because we take feedback from experts and fans seriously. It would be inconsistent to stop now – on the contrary, we are very eager to receive it and look forward to constructive input! Furthermore, our technical approach makes it possible to implement changes at short notice …
Could the sound design concept of the DTM Electric also be transferred to other cars – for example, electric production cars?
Blickensdorff: Certainly. The sound levels required would probably be far lower, thanks in part to the legal requirements, which would reduce the effort involved. However, the setting of goals and set-up on the car itself should not be underestimated.
How are the concepts of sound design for electric cars in production different, if not actually contradictory, to those in motorsport?
Blickensdorff: Motorsport is entertainment, passion and pure emotion. Any findings here make their way into production development in the short or medium term. The sonic freedom when designing sounds in motorsport is far more progressive and dynamic, as the driving dynamics and sound pressure level to be generated are very different.
Sound for electric cars is sure to be one of the dominant topics in the automotive industry over the coming years. Sound technology to make vehicles more emotive is definitely particularly interesting for sports car manufacturers. Are collaborations conceivable, and are discussions perhaps already taking place?
Blickensdorff: We want to make the DTM Electric, and with it the “swarm sound” of the race cars on the track, far more interesting. For this purpose, every team with our technology can also fine-tune the sound of their car. We have already demonstrated our system to some customers, live on the car. There is definite interest and initial discussions have already taken place.
The emotive soundtrack for electric motorsport
Listen to Dr. Jochen Schröder, Schaeffler’s E-Mobility Division President, as he explains why the sound of the DTM Electric is so special.