Meet the people who make sure a
This is clearly not your average sound studio. The walls are covered with gray, wedge-shaped sound-insulating elements; in the middle, a Mahogany Metallic 911 is mounted on a dynamometer. In front of it, the device resembling an oversized microphone is actually an acoustic camera. Welcome to the realm of
Here in the acoustics lab in Weissach, Dr. Bernhard Pfäfflin, head of development for vibration technology and acoustics, and his team compose the unmistakable
These soundtracks—including the thrilling melody of the naturally aspirated boxer engines, the crescendo of the valve trains, and the tempered trumpeting of the exhaust system—can be mixed on the computer and fine-tuned in a manner similar to a musical recording. When a new model is being developed, the sound experts know what it will sound like even before the prototypes hit the track. And, of course, there are always improvements to be made to comply with ever-stricter noise restrictions being imple-mented in countries around the world. The challenge is to make cars noticeably quieter to the outside world while simultaneously transmitting the wondrous sound of the
The term “sound design” can be somewhat misleading, as it suggests that the sound of the car in action can simply be constructed and played back like a recording. But the song of the
The Weissach team uses applied physics dating back to scientist Hermann Ludwig Ferdinand von Helmholtz, who lived and worked in Berlin some 150 years ago. His insights into acoustics are still valid today. As a matter of fact, sound experts still swear by the formula, “If you’ve got a handle on Helmholtz, you’ve got the sound under control.” The Helmholtz resonator, which von Helmholtz developed to help him identify frequencies and musical pitches, has been used by
But one principle remains ironclad: it can’t sacrifice power or torque and it can’t increase the weight—let alone decrease effi-ciency. “We’re relentlessly uncompromising here at
Another system the acoustics team uses to highlight the
What does that mean in practice? As soon as the driver hits the Sport button on the center console, sharpening the responsiveness of the transmission, engine, and suspension, the flaps in the sound symposer and the Helmholtz resonator open to allow unrestric-ted flow, intensifying the natural sound of the
The acoustic feedback doesn’t just add a bit of oomph to the driving experience—it also sharpens the driver’s perception of the engine’s degree of exertion. The driver should have a direct and unvarnished take on exactly how much of the
One thing that the sound makes clearer is acceleration. An overly quiet car—acoustics experts refer to this as decoupling—could lead the driver to underestimate speed. A lack of sound could lure some drivers into thinking that they are moving quite slowly at 200 km/h. Such a misapprehension not only could make it more difficult to adhere to the speed limit; on highway exits with tight curves, for example, a precise sense of the car’s degree of exertion plays a very important role. This sense of speed makes it much easier for the driver to assess the appropriate limits. With largely decoupled acoustics, the driver can only rely on the speedometer, whose abstract signal can lead to misinterpretations.
The acoustics engineers spend a great deal of time filtering out irritating noises. Bernd Müller, sound designer for the
To soften the high-pitched clickety-clack of the valve train, for example, the acoustics pros painstakingly develop ribbed valve covers. Likewise, power motors for the steering, air-conditioning system, and windshield wipers have nothing to do with dynamic car control and should ideally fade away into the orchestra pit of oblivion.
Now you might think that the rear- and mid-engine model lines—the 911 and the
Artificially generating sounds and adding them to the drive spectrum through speakers is absolutely out of the question. It’s a bit like the German beer purity law, the “Reinheitsgebot,” which prohibits all artificial aromas and additives. What you hear is only what the engine begets: Pure
By Michl Koch
Photos by Bernd Kammerer
* Data determined in accordance with the measurement method required by law. Since 1 September 2017 certain new cars have been type approved in accordance with the Worldwide Harmonised Light Vehicles Test Procedure (WLTP), a more realistic test procedure to measure fuel/electricity consumption and CO₂ emissions. As of 1 September 2018 the WLTP replaced the New European Driving Cycle (NEDC). Due to the more realistic test conditions, the fuel/electricity consumption and CO₂ emission values determined in accordance with the WLTP will, in many cases, be higher than those determined in accordance with the NEDC. This may lead to corresponding changes in vehicle taxation from 1 September 2018. You can find more information on the difference between WLTP and NEDC at www.porsche.com/wltp.
Currently, we are still obliged to provide the NEDC values, regardless of the type approval process used. The additional reporting of the WLTP values is voluntary until their obligatory use. As far as new cars (which are type approved in accordance with the WLTP) are concerned, the NEDC values will, therefore, be derived from the WLTP values during the transition period. To the extent that NEDC values are given as ranges, these do not relate to a single, individual car and do not constitute part of the offer. They are intended solely as a means of comparing different types of vehicle. Extra features and accessories (attachments, tyre formats, etc.) can change relevant vehicle parameters such as weight, rolling resistance and aerodynamics and, in addition to weather and traffic conditions, as well as individual handling, can affect the fuel/electricity consumption, CO₂ emissions and performance values of a car.
** Important information about the all-electric