That's entertainment

The majority of 4x4 drivers in the UK are probably not that concerned about how their vehicle handles off-roading in the Cairngorms. For the urban SUV driver, more important is that their Chelsea tractor is big enough to take a handful of children, assorted gym kits, the weekly shop and a large dog while providing a safe, comfortable ride. It is perhaps in this context that the in-car entertainment system takes on more importance.

Land Rover’s latest award- winning 4x4, the Freelander 2, was launched last month in the UK to much fanfare and admiration from the automotive world for its performance, styling and all-round good looks.

Lauded for both its off-road performance and its luxurious, spacious interior, Land Rover has also done its best to make the Freelander as ‘green’ as possible, with a claimed 38 mpg and emissions no worse than a conventional saloon.

In terms of developments in new driving features, two new technologies debut on the vehicle. Roll stability control is the ‘most sophisticated roll-over prevention technology ever fitted to a Land Rover’, according to the company. Gyroscopic sensors allow the system to compare how the car’s body angle changes with the course that is being steered as it turns. If necessary, incremental brake force is applied at the outer wheels, automatically altering the turn radius to help prevent the roll.

Another innovation that makes its debut is Land Rover’s patented gradient release control system. Linked to the hill descent control, this ensures that, when releasing the brakes on extremely steep hills, brake-line pressure is released progressively, helping to maintain full driver control.

However, it is the in-car entertainment that really differentiates the Freelander 2 . It is the first automotive application of Dolby’s Pro Logic II 7.1 surround sound technology, more usually found in top-of-the-range home cinema systems or in the cinema itself.

Ever since the 1960s, when Dolby launched its first noise-reduction technology, the firm has been at the forefront of sound technology. In 1975 it launched Dolby Stereo, its first foray into what was to become surround sound. This was developed for the cinema and encoded four channels of audio into the stereo film soundtrack, with the fourth channel used to create a more immersive experience.

The next step was for people to try to re-recreate the cinema sound experience. Dolby’s Pro Logic system allowed users to create as near as possible a cinema experience in the comfort of their own home.

In 2001 Dolby launched its latest surround sound technology, Pro Logic II. This system improved the surround experience by using algorithms that could recognise directional clues in the source material and delivered a five-speaker experience, which was a much more realistic reproduction of how the original materials had been recorded.

Cleverly, Pro Logic II is able to pull direction sound clues from almost any source material, in theory breathing new life into old material.

In the automotive industry, surround sound has long been a popular option, particularly in top-end models. Dolby’s Pro Logic II 5.1 system is standard across Volvo’s range and has also appeared on Jaguar’s latest XK sports car, while the new Mercedes S-Class will also incorporate a full 5.1 surround sound in-car entertainment system. The figures ‘5.1’ in this case refer to the five speakers, front left, right and centre, two rear speakers and the 0.1 indicates the presence of a sub-woofer for bass sounds.

Now, for the first time, Land Rover is incorporating Dolby’s 7.1 technology in a car. Ostensibly 7.1 works in the same way as 5.1 except it has two new channels of sound that cover the mid-range. Dolby’s 7.1 processes simple, two-channel stereo audio into seven individual playback channels, plus the sub-woofer. For the Freelander this meant incorporating 14 different speakers in the car.

Dolby’s Simon Arnold explained how the sound is processed. ‘The 7.1 system adds two more channels of information,’ he said. ‘In automotive applications we need this because we can have up to three rows of seating in a compact space so, to ensure a good sound experience for all three, you need a mid-row of extra information.’

Arnold explained that the difference between automotive surround sound and the systems to which most people are accustomed is that in the cinema — or at home — most people are sitting in a row, surrounded by speakers.

One of the main challenges in developing surround-sound systems for cars is ensuring that everyone within the car experiences the same sound quality. This is difficult, particularly in large vehicles such as the Freelander or the even bigger Discovery. Often the passengers sitting much closer to the rear surround speakers — used to provide ambient background sounds — will not be able to hear the sounds as well as those sitting in the front.

Dolby’s intelligent Pro Logic II algorithms will, to a large extent, solve this problem, Arnold said, while the additional two channels provided in 7.1 will enhance the experience.

‘What you are aiming to achieve is for every passenger to get an image of the vocalist in front them with the rest of the instruments placed around as the artist originally intended,’ he said. ‘In a stereo system that’s easy for one person but not for multiple listeners.’

Pro Logic II surround decoding produces a central image for all passengers, which provides ‘sweet spots’ not just left to right but front to back as well.

These Dolby algorithms have different settings to achieve the right effect for individual cars.

The Freelander 2 also signalled another debut: the first Land Rover sound system to have been developed and branded by car-audio specialists, Alpine. Dolby and Alpine have a relationship that spans many top-end cars, including the Aston Martin Vantage and Jaguar’s XK, but this is the first time Alpine has developed a full system for Land Rover.

Engineers from both Dolby and Alpine collaborated on the Freelander project to work out the optimum setting for the surround sound in a way that took into account the vehicle’s unique interior, filled with both reflective and absorbent materials.

Keith Price is Alpine’s senior manager for product development. He said that this ‘sound management’ was one of the biggest technical issues facing the team. ‘This is the first time anyone has done this in a car,’ he said. ‘From the sound-quality point of view the challenge is in balancing the overall sound quality of the car.’

While this is the first full sound system that Alpine has developed for Land Rover, the firm has worked with the car giant in the past on individual technologies.

Alpine’s experience in the area of 4x4-specific sound systems paid dividends as its engineers had to develop a system that could cope with the unique demands of a real off-roader. The CD player has to be able to cope with inclines of up to 30º and so Alpine uses advanced skip-memory features and anti-vibration mountings to ensure music fidelity —now in glorious 7.1 surround sound — on even the roughest of mountain tracks. Or the dangerously unpredictable and rugged terrain of the two-mile school run.