There is no question that an important part of the BMW experience includes the excitement of hearing the engine race through its rpm range while at the same time being insulated from the harsher noises that are sometimes a feature of modern urban or highway landscapes. The type of pleasing audio environment provided by each and every BMW automobile is no accident – rather, it is the end result of millions of dollars and thousands of man-hours spent researching and developing the latest in sound control and sound design technologies.
Nowhere is this supreme effort easier to distinguish than in BMW’s expanding lineup of advanced diesel vehicles. The luxury brand has already invested so much in terms of producing diesel engines, which offer the combination of great fuel efficiency, incredible power and impressively low emissions that it was only natural to turn the attentions of its engineers and designers toward developing the next generation of BMW sound technology to accompany these motors. The goal of the company has been to introduce a sound experience that matches up with a diesel engine’s performance and allows BMW drivers to make the same spiritual connection with these models as they have for decades with the automaker’s gasoline-powered models.
The first challenge undertaken by BMW was to create new and more efficient methods for controlling and reducing vibration. The key to achieving this goal was to shy away from the standard methodologies that simply added thicker levels of insulating material to an automobile, increasing its weight while simultaneously decreasing its performance. Instead, BMW engineers set out on a path which saw them completely redesigning key engine components to feature a new ribbed exterior that is specifically meant to dramatically lower the transmission of any vibration. By addressing noise at the source, it became possible to build diesel engines that are far quieter than those produced by the competition without the need to double or triple the use of traditional insulation materials.
In addition to this breakthrough design concept, BMW also elected to replace parts of its diesel-equipped vehicles with a new structure made of a substance called lightweight reinforced thermoplastic (LWRT). This unique material is not only capable of improving the aerodynamics of an automobile, but it can also act as an insulating material, removing the need to include additional sound deadening during installation. LWRT is lighter and more effective at blocking out sound than past insulators, and since it is an integral part of the subframe itself, it has allowed the undercarriage to become as much as 15 times thinner than those on older, insulation-dependent designs.
The end result of these sound control innovations is a fleet of diesel cars that are as quiet as their gasoline counterparts, whether you are standing beside an idling example or sitting in its passenger compartment. Of course, a peaceful automobile might be relaxing, but it does not exactly evoke the passion that BMW vehicles have historically been known to inject into the blood of enthusiasts, and this takes us to the final piece of the company’s sound management puzzle: Active Sound Design.
Active Sound Design is the term for the technologies used to connect a BMW driver with the most pleasing range of sounds produced by a vehicle while it is being driven. Careful research and experimentation have allowed BMW engineers to install a digital signal processor in each diesel-powered vehicle that not only augments the highlights of the engine’s natural audio characteristics, but that also generates its own special tones, which interact harmoniously with the vehicle’s operation. The processor monitors every aspect of the driving experience in order to appropriately match the sound heard by the driver with the current engine speed and road conditions, maximizing smile-inducing sounds and keeping those behind the wheel completely in tune with every thrilling note the vehicle produces.
Active Sound Design is unquestionably one of the most forward-thinking notions to have ever emerged from the luxury car industry. It is no surprise that it took the enthusiasm of BMW to ask why diesel automobiles could not offer a soundtrack that matched their exceptional performance and acceleration. BMW’s devotion to sound control and sound design is merely one facet of the brand’s refusal to accept the status quo – especially with regards to improving the driving experience of each and every one of its loyal customers.