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Top Gear Magazine Awards 2016

How does the Range Rover Sport SVR sound so good?

We delve into the art of noise to find out just why the SVR gives such good vibrations

  • The sound of a Range Rover Sport SVR, at first, it sounds like a distant Chinook helicopter, all low and rumbly and full of trouble. When it really gets going you might mistake it for a passing NASCAR. For an SUV, it's fantastic, and utterly riotous. So let’s go inside Range Rover’s acoustic bunker, known properly as the NVH department, to see how they make this thing sound so good.

    NVH is industry-speak for noise, vibration and harshness, and people in this line of work devote much of their lives to making car cabins hushed and peaceful places in which to be. But occasionally they’re asked to go full Spinal Tap, and create a rock ’n’ roll sound worthy of the fastest Range Rover ever built.

    Photography: Richard Pardon

    This feature was originally published in the May 2016 issue of Top Gear Magazine.

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  • While early development is done with computer models and driving simulators, there’s no substitute for the live act. For this, the car is strapped to a rolling road inside a semi-anechoic chamber, a room insulated from outside noise and lined by foam stalactites that absorb sound reflections. Only here can you get a true picture of a car’s acoustics, free from echoes or any other sonic interference.

    The recordings taken here allow engineers to analyse exactly what sounds are being created at various speeds and under proper engine loads, then determine how they might be tweaked or improved. The science behind all this can induce long-lasting headaches, but here goes…

  • Every car makes a noise, but only a handful make something resembling music. To become musical, a sound must have a few properties: an identifiable pitch, a quality of tone and a steady rhythm. Some engines don’t sound very pretty – just think of an average four-cylinder – yet others such as a big V8, well… you could listen to them over dinner. Why?

    Let’s take the SVR’s V8, which – thanks to its cross-plane crankshaft – has an irregular firing sequence. So rather than the two banks of cylinders firing alternately, one bank might fire twice, followed by one from the other side, and so on. This means the air is forced out through each exhaust (one per bank) in irregular, yet recurring, pulses. At low engine speeds, you will hear this as a typical V8 throb-throb, but as rpm increases, these pulses blend together and become tonal, forming what musicians call a harmonic series.

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  • But fundamentally we’re talking about air being blown from an engine and down a pipe. It’s the same for all cars, but whereas a dull, in-line four-cylinder may produce a monotonous drone, a large V8 has more musical potential. So think of it this way: the SVR’s exhaust is like a trumpet, blown by a 5.0-litre, supercharged V8 with more lung power than Louis Armstrong and Miles Davis put together. And like any wind instrument, it can be tuned, and that’s when the magic happens.

    For example, when the pipes pass through the front silencer (a bit of a misnomer in a car as loud as this), air is allowed to escape through tiny holes so that the pulses from each side become mixed, before continuing rearwards. On top of this, the engineers tweak all sorts of stuff from the length, shape and diameter of the tubes (60mm up from 55 in the standard car), and this all has an effect on the character of the exhaust’s sound.

  • Think of each pulse as a musical note, and when these notes are played together, they effectively form a chord. That’s what the exhaust is doing. There might only be three or four notes being played, but each occurs at a different frequency. The overall effect is like an orchestra – while a cello plays a low C, a violin plays a high C. It’s this mix of different frequencies that gives the sound its character.

    But the SVR’s real party trick is the pair of electrically controlled valves in the tailpipes, which open at around 3,000rpm allowing maximum airflow and therefore maximum noise – about 110dB if you stand close by. We’re fairly used to these loud flaps in sports cars, but this is the first time we’ve seen them in a Range Rover, and we’ve not experienced any as raucous as this.

  • The engine map is also programmed to slightly over-fuel, causing unburnt petrol to pop and crackle through the hot exhaust system when you come off the throttle. Again, not unusual, but the SVR seems to revel in all of this, where others seem a touch apologetic about such festivities.

    And that’s the thing: despite all the legislation controlling noise and emissions, and despite social pressures in a world of fashionably-quiet electric cars, the SVR team has made a machine that could terrify your gran. Which is why the TopGear Award for the Noise of the Year goes to them, for having the sense of humour – and the guts – to make it happen.

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