The future has a whole new sound


EVER your view on electric and hybrid cars, driving around the city in one of them in near silence is something that takes a lot of getting used to for some drivers. Spare a thought for pedestrians too, particularly those with sight problems. Traffic, in the absence of engine noise, is a potentially frightening, even dangerous proposition.

If you’ve dreamt of living in a city devoid of car noise as we all pootle about in our silent milk-float-like vehicles then you’re going to be disappointed. Research in the US has shown that a hybrid or electric vehicle is twice as likely to be involved in a pedestrian accident than a car with a conventional combustion engine, particularly when slowing or stopping, backing up, or entering or leaving a parking space. Which is why carmakers – and companies like acoustic experts Harman Kardon – are busy developing sound systems for cars like this Toyota Prius.

Which is why I find myself driving around Crouch End in a hybrid Toyota Prius that sounds like a Cylon spaceship one minute and an American V8 the next. The car looks just like any other Prius, except this one is a demonstrator for a new electronic sound system that warns people of your otherwise silent presence by synthesizing sound to speakers located on the inside and (crucially) the outside of the car. The effect is surprisingly easy to live with, if unusual.

The system works by placing sensors on the throttle and braking pedals. A synthesizer then transforms these inputs into “engine” sounds that are then transmitted via a speaker at the front of the car – for pedestrians to hear – and inside the cabin to give the driver feedback too. It’s tailorable so this car can switch the sound it makes from the American V8 to a V6 and a V12 engine, not to mention a couple of futuristic sounds which have more in common with a light saber than a combustion engine. In Crouch End at least, it would seem that the V8 blends in to the other traffic noise rather more than the futuristic spaceship sound, if the looks from passing pedestrians are anything to go by.

Without realising it, all of us have come to rely on the volume and pitch that a car makes to work out how far away it is when we’re walking. At higher speeds pedestrians can hear HEVs (hybrid electric vehicles) thanks to road and tyre noise, but up to around 30mph, people are going to need electronic help to replace the mechanical noises that conventional cars make.

At the moment it looks like legislation will most likely call for HEVs to electronically recreate the sound of a combustion engine because that’s the sound people are already used to. But in theory driving around a hybrid or electric car equipped with such a system could mean a car could sound like almost anything. Fancy a car that sound likes a Zen garden wind chime, the Starship Enterprise, or waves crashing? Entirely doable. Fortunately such sounds will be limited by what carmakers deem appropriate and the boundaries set by legislation, so you’ll have to keep them to the inside. Which must be a much better option than a cacophony of branded engine noises blaring out at a crossroads like disparate Crazy Frog ringtones.