With fuel costs perpetually on the rise, the popularity of electric and hybrid/electric vehicles is following suit. In eliminating vehicle petrol consumption, however, another problem arises: eliminating the sound of combustion engines that pedestrians and cyclists have become accustomed to hearing on the roads.
Electric vehicles are quiet: deadly quiet. At the University of California, Riverside in the US, experiments have shown that electric vehicles (or hybrid vehicles running in electric mode) need to be 74% closer to subjects before they could hear them. In the real world, that means not being able to hear an electric car until it’s one second away: hardly enough time for any effective avoidance manoeuvres.
Once finalised, European legislation will determine just what kinds of sounds electric vehicles will need to make, and how loud they’ll need to be. (One experiment in Holland has already seen a Domino’s pizza delivery scooter using specially recorded sounds to alert pedestrians to its presence. [Link http://www.youtube.com/watch?v=n17B_uFF4cA]) But if the sound is changing on the outside, what about interior sounds?
Using his skills as both a film composer and a record producer, music producer Steve Levine (pictured below) has been in the studio working on the design of sounds inside electric vehicles “so you do get the sense of acceleration, deceleration, all the things that give you comfort when you’re driving”, he explains. “People are used to a combustion engine of some sort, and therefore the inherent feeling that that car gives you in terms of you awareness of speed, safety and all those things. That’s part of task in creating the various sound sets.”
Levine stresses that the sounds inside the vehicle aren’t simply a collection of samples and loops playing over and over again. “This is a fully interactive replacement to the sound of what a combustion engine would do,” says Levine of the work he is doing with HALOSonic: a partnership between Harman Professional and Lotus Engineering (hence, HALO).
The system combines technologies created by each company: from Lotus, a software algorithm originally created to rapidly process active suspension systems on F1 cars. From Harman, synthesis and sampling technology that can employ algorithms used in Lexicon reverbs and delays, HardWire’s “staggeringly brilliant” guitar pedal technology (think of how you accelerate in a car) and the amp modeling algorithms found in DiGiTech software. It was Levine who initially saw the potential to exploit Harman’s pro-audio technology for HALOsonic.
“I pointed out the hardware connection to them,” says Levine. “It didn’t seem to dawn on them. It puts Harman in a unique position because not everybody has access to such a huge, diverse set of technologies. The work is in creating those algorithms; once you’ve got them you can do a lot of other things with them.”
The idea behind HALOsonic’s soundsynthesis isn’t much different to that of plug-in architecture. Impulse responses are made of the individual components that make up a vehicle’s combustion engine; spark plugs, cylinders, cam shafts, pistons, etc. An infinite number of subtle changes to the sound are possible to from that “core DNA” of modeled components, “rather than sampling the sound of an engine as a completely ‘dumb’ thing,” says Levine.
Although Harman’s own survey suggests that, for the time being, drivers still want their electric vehicles to sound like a conventional car, Levine imagines it won’t be too long before we are customising car sounds the same way we customise ring tones, or even creating them ourselves.
“It’s very interesting because no one ever imagined phone apps taking off the way they did but Apple gave people the tools with which to create them and I think that’s what we’d like to try and do,” he concludes.