Turbochargers have many advantages. They use exhaust gas to give us more power and lower fuel consumption, and in doing so they kill most of the exhaust noise. That is brilliant in a normal hatchback or a family saloon, but in a sports car or a hot hatch, that is not such a good thing. Which is why Ford invented a new sound symposer for the new Focus ST, so you can have your cake and eat it too.
The trick they’ve used is clever, but pretty geeky. And in the the end the noise it makes is kinda fake. But as long as you get the sensation of driving a properly hot car, it doesn’t matter. BMW uses a similar system in the new M5 for crying out loud.
Ford’s system boosts engine volumes into passenger compartment in 200-to-450-Hz frequency range, which is said to be the most pleasant. The system uses a composite “paddle” that vibrates with intake air pulses. In lower gears, the valve is mapped more aggressively, while in higher gears the effect is dialed back to enable quieter cruising.
The upshot of all this is that you get a deep, throaty noise, and because it’s acoustically tuned it’s also very crisp and clear.