The new BMW 8 Series, whether in the coupé, gran coupé or convertible, is a sports car for aesthetes. And what goes for the look and performance, also applies to the sound. From super-sporty to exceptionally elegant, the sound of this unique sports car embodies all the characteristics of the dynamic luxury racer. So what does the highest quality and maximum performance sound like? We visit the sound masters at the test site in southern France.

The BMW test site Autodrome de Miramas in southern France is a world of its own. Step into it and you find yourself entering a microcosm of prototypes. Almost every car that is put through its paces here is still top-secret and camouflaged. The prototypes – both cars and motorbikes – that speed past you here are covered completely or partially with foil in psychedelic black-and-white patterns. When the track is open for standard testing, vehicles can be seen suddenly appearing from behind steep curves and roaring past crash barriers; however, sometimes the tracks are exclusively reserved, as in this case with Dr Robert Liebing and his team: the BMW sound designers.

Robert Liebing is responsible for Development Overall Vehicle Sound Design at BMW, which puts the 39-year-old in charge of all sounds and noises that one hears inside and outside a BMW: the sound of the engine, the control functions, and the indicators – none of these sounds are left to chance. 

Injected or vapour deposited anti-noise coatings are used to make large metal surfaces quieter; special rubber bearings – called absorbers – prevent vibrations from being transmitted; sound insulation specifically encapsulates unwanted noise. In technical jargon, this is called “insulation and damping”. “The basic sound hygiene of the vehicle is produced through passive acoustic optimisation," says Liebing. All sounds must be coherent, associative, must convey value and luxury, must sound like a top-of-the-range car, and, most importantly, must have the typical sound of a BMW.

EXPERT EQUIPMENT

For Liebig’s team in Miramas, 30 per cent of the work is done by computers, 70 per cent is typical everyday test work that involves lots of driving. The key tool here is a special set of headphones with external microphones, which Daniel Schock wears as he test-drives the 8 Series Coupé. Schock, 29, is 'Engineer for Characteristic Sounds, Luxury Class', which is why he works on the new 8 Series. “The headphones are our standard tool, and we always have them to hand. They are required for fine tuning, to record all the noises a car makes and then to analyse them,” explains Schock.

Liebing nods. “Experts like Daniel have incredibly detailed hearing, which is enormously important because sound design isn’t really something you can learn; you have to have it in your blood. But there are moments when you need a precise measurement, for instance to find out what exactly isn’t quite right about a sound: is it a second order or a fourth order? The octaves are particularly difficult,” says the sound expert.

KNOW YOUR SOUNDS 

For all those not familiar with the terminology of sound design: “orders” are like the fingerprint of an engine. Boxer, V-engine, in-line six – all engines have different ratings within these orders, and thus produce different sounds. The sound of a six-cylinder in-line engine, for example, is determined by the third and sixth order and, because there are no “equal” (loud) secondary orders, it is smooth. The eight-cylinder engine has the fourth as the main ignition order, but when it is loud secondary orders also appear, about 2.5 and 4.5, which create a rougher sound. Complicated as this seems, it all has to be taken into consideration when fine-tuning the sound of an engine.

A UNIQUE SOUND

So how does one set about designing the sound of an 8 Series Coupé? The engine of the luxury sports car delivers as much as 390 kW (530hp) in the eight-cylinder M850i xDrive version and has all of BMW Motorsport’s racing genes in its DNA.

“The sound of the 8 Series expresses strength and agility, both of which are key characteristics of BMW,” says Liebing, an electrical and communications engineer with a doctorate in psychophysics. “It has to be a unique sound which no other car has. That’s another characteristic of a BMW. All sound components in the interior are fine-tuned to match the car. The sound, the lighting, the tactile qualities of the car – everything has to harmonise, has speak the same language. This is luxury that you only find in the premium segment.”

The big challenge in designing the sound for the 8 Series was to ensure that when the car is driven dynamically, the engine sounds powerful and agile, and during constant, even driving you practically can’t hear it.

The journey towards a perfect sound covers the entire product development cycle. “In the planning phase, which is long before the car actually physically exists, we look at various engine concepts,” says Liebing. “We listen to cars that have a distinctive sound character and then try to apply our findings to the typical BMW sound. Dynamics, for example, are always a characteristic value, as is sportiness, but value or quality are also important aspects. These are all things that we need to express in the engine’s sound. We never set out to replicate a very high-revving, very bright engine sound, for example, as is common in Formula One, in a BMW sports car. It may well be a very dynamic, very sporty sound, but it doesn’t express quality, and that means that it’s not BMW.”

ALL-ENCOMPASSING SOUND

Daniel Schock adds: “We know we’ve done a good job when the sensory impressions form a coherent overall picture, when they are balanced and do not compete with each other. This is the moment when driving pleasure becomes all-encompassing.” Five of the BMW sound designers are currently in Miramas, ten others are testing at the Bavarian BMW test site in Aschheim near Munich.

PITCH PERFECT

Winter, rain, snow, fog are all conditions that make the sound architects' work difficult. And, as BMW normally test multiple new models and time is of the essence, this plays havoc with the tight schedules.

In contrast, the testers have ideal conditions in the south of France: there are more than 52 kilometres of covered test tracks and office workplaces for around 330 employees. In Provence, even in December the thermometer reads 16 degrees and higher. For more than 30 years, BMW has been testing its new models and technologies on the former racetrack that lies between Marseille and Arles.

In 1986, the BMW Group purchased the 473-hectare site and has since then added numerous test tracks, including a replica of the famous Nürburgring carousel with the legendary Caracciola curve. “The sports cars in particular are often pushed to their limits during these tests. Passion for cars, an instinct for the interplay between the sound and the response of the car, i.e. a certain degree of driving skill, are all basic requirements for BMW’s sound designers,” says Liebing with a grin.

SOUND HAS TO UNFOLD

In Miramas, the mechanical chassis components and electronic control systems have to handle gruelling conditions, depending on the speed – but this should never be audible inside the car. The engine also has to show what it is capable of on the road – and whether it sounds like it ought to. “As the speed increases, the sound of the engine must also rise,” says Schock. “It must unfold like a bouquet of flowers. The sound should become richer and more promising. And as far as I’m concerned, it can also sound a bit wicked. The engine should be telling you: ‘I know there’s an electronic limiter, but that doesn't bother me at all – I just want to keep going faster.’”

One aspect is particularly important: the engine must never sound strained. “BMW cars stand for sportiness and dynamics,” says Robert Liebing. "They should never, ever sound as if they’re running out of breath or have any kind of limitations, not even when they’re running at full capacity, accelerating or climbing a steep hill. And this applies especially to the new 8 Series, BMW’s new luxury sports car."