So how does a Jaguar sound? Does it roar? Or growl? Does it purr? And we're not talking about the four-wheeled Jaguar here, more the jaguar of the four-legged kind.
You see, Jaguar's interior design team had this idea during the development of the new XF. They'd just devised the new Jaguar ‘handshake' start sequence where, at the touch of the pulsing start button, the air vents rotate and the cylindrical JaguarDrive Selector rises up from the centre console.
“We wanted to continue with the drama, as well as have a little bit of fun,” explains Wayne Burgess, senior manager for Jaguar Design.
The design team's idea was to incorporate the XF's revolutionary new Bowers & Wilkins 440W surround sound system into the car's start-up sequence. The thinking was that after the vents had rotated, and the JaguarDrive Selector had risen, a digitized jaguar would appear on the car's touch-screen. At the moment it would turn to face the interior of the car, a jaguar ‘growl' would be played through the Bowers & Wilkins' speakers.
“We were really serious about doing this. We had our technicians get hold of a jaguar recording and incorporate it into the start-up sequence.
“Then we played it, and almost scared ourselves to death. The amazing clarity of the sound made it seem like there was a real live jaguar sitting on the back seat. It was just too realistic, and much too scary,” he explains.
While Burgess' plan didn't quite pan out, Jaguar's team of more than 80 different sound engineers work on other ways of making every new Jaguar purr, growl and roar.
That hard-edged throaty roar of a supercharged XKR as its tachometer needle spins around the dial? It didn't get there by accident. Nor did the refined V8 growl of an XF 4.2-litre. Or the hushed, distant purr of an XJ 2.7-litre turbo diesel.
"In essence, what we try to achieve when we develop a new Jaguar is a duality," explains Garry Dunne, Jaguar's technical leader for Vehicle NVH and Sound Quality. "We want our cars to be able to be driven at low speeds and have a soft, mellow growl. Then when you extend them, you get a more aggressive, more exciting, more rewarding sound."
Dunne says this duality is what sets the Jaguar marque apart from the competition. Most rival cars to the XK, for example, are either always ‘on', sounding loud and aggressive from the moment you turn the key. Others are too hushed, refined and soul-less for a two-seat GT. Jaguar offers the best of both.
Dunne operates Jaguar's three UK sound ‘studios', better known as Vehicle Semi Anechoic Chambers. Here is a world of sones, hertz and decibels. It's where rewarding acoustic signatures are embraced, and noise, vibration and harshness shunned.
The chambers are giant, bleached-white rooms lined with sound-absorbing acoustic wedges on the walls and ceiling. In the centre, on the floor, is a rolling road where a car can be strapped down and run up to 175mph (282kph) without moving an inch. This is also home to Bart and Homer, Jason and Lisa – four of the 12 acoustic ‘heads' used to detect the sounds human occupants hear inside the car.
"It would be rude not to give them names. They play such a key role in the work we do," says Dunne.
Each of the heads have microphones embedded into ear canals and can listen to sounds the way humans do. The only difference is the sound going into Bart and Co's ears can be downloaded on to a computer and evaluated digitally. It's those computers that allow Dunne and his team to take a vehicle's sound and ‘de-compose' it into its constituent elements. It allows them to identify the part of the sound that comes from the engine's intake system, exhaust, engine mounts or from the road surface. If the sound engineers identify too much of the wrong kind of noise coming from, for example, the induction system, they can call for them to be modified.
"It's a bit like tuning an instrument – with a lot of strings. It takes plenty of patience. The engineers' role is to identify the problem and try different tuning and engineering solutions, to get the right sound character. It demands a lot of man-hours."
So what is the right sound character for a Jaguar? Mick Mohan, Jaguar's director of programmes, and the former chief engineer during the development of the XF, says the decision is made right at the beginning of the development process.
With a car such as the new XF, it meant improving the sports-saloon character – compared to the previous S-TYPE – giving the car a sportier, harder-edged sound at higher revs. Yet Mohan's team still wanted it to sound extremely refined at lower speeds.
"Right at the beginning of the programme, when we were developing the XF diesel, we decided that in order to achieve class-leading diesel refinement, we needed a second bulkhead between the engine bay and passenger compartment. It worked so well with the diesel engine that we decided that all XFs – not just the diesels – should feature it. It really helped us change the character of the car," explains Mohan.
Also during the early stages, Mohan's team decided that to be a true sports saloon, the XF needed the stiffest, most rigid body structure in its class: "Great sound quality starts with a stiff, super-rigid body shell. It's the key to reducing the likelihood of any squeaks and rattles, to producing a solid, quality-feeling car."
He explains that the XF's body structure uses no fewer than 25 different grades of steel, from mild to ultra high-strength. One of those 25 different grades is called Boron, and it's 900 per cent stronger that regular mild steel, So strong, in fact, that you have to heat it to a temperature of 450 degrees Celsius before it can be formed.
Mohan also laboured over every single detail inside the XF to ensure it had the correct sound quality. Everything from the closing of the doors to the whirr of the power front seats.
"On the XF's centre console, we have this lovely piece of timber that covers the cup holders. Our challenge was making the sound it made as it closed in keeping with the premium image of the car. “Because the wood looks like it came from a piece of furniture, we started looking at furniture for inspiration. We found a beautiful cigar box that closed with this lovely-sounding, solid clunk. That's the sound we replicated," explains Mohan.
So whether it's the clunk of a cup-holder cover or the growl of the engine, everything you hear in an X-TYPE, XF, XJ or XK really is the true sound of a Jaguar.
HOW TO CREATE NOTE-PERFECT SOUND, THE JAGUAR WAY
1. The exceptionally strong, rigid body shell reduces squeaks and rattles
2. An active exhaust on the XK/XKR keeps the engine refined while cruising, but produces an increased roar under hard acceleration
3. An intake duct channels noise back to the vehicle cabin to deliver a rewarding edgy snarl at high engine speeds
4. The XF's double-skin bulkhead improves refinement of the diesel versions, and allows better sound tuning for petrol models
5. A three-layer laminated ‘acoustic' glass is used for the XJ's windscreen. This reduces cabin noise by an impressive five decibels
6. The 2.7-litre twin-turbo Diesel XJ features electronically controlled active engine mounts that cancel 90 per cent of engine vibration at idle
Jaguar set a new benchmark for in-car entertainment with the remarkable Bowers & Wilkins 440W surround sound system developed for the new XF. Engineers from the UK-based company – one of the world’s most respected hi-fi speaker companies – were involved in the XF’s design from the earliest concept stages.
"Right from the beginning we worked with Bowers & Wilkins to ensure the correct positioning for the system's 13 speakers and sub woofer," says Wayne Burgess, senior
manager for Jaguar Design. "Normally, speakers go at the bottom of the doors where they sometimes get kicked and essentially play music to your feet. In the XF, we managed to integrate them mid-way up the door at the front leading edge. It makes the sound quality remarkable," explains Burgess.
Jaguar and Bowers & Wilkins continued their relationship with the development
of an integrated audio system – with a staggering 525 watts of power – for the limited-edition XKR-S.
[Issue 2, 2008]