AUDI is developing a series of synthetic sounds for its upcoming electric models.
The noises, developed by the German brand's acoustics engineers, have been designed so pedestrians will be able to hear the cars in the urban environment.
The sounds also work to give the otherwise near-silent-running EVs a sound signature - in much the same way as a Porsche, Ferrari or V8 muscle car has its own unique sound - and each of the electric Audis will have its own similar but slightly different tone.
The sound is transmitted from a speaker under the body of the car, and Audi claims it can be heard by passersby, pedestrians and cyclists, and is expected to operate at speeds up to 30km/h.
The company says it has looked at a range of sounds, including some from science fiction, but, as Audi acoustics engineer Rudolf Halbmeir says, "there was nothing in the real world which offered quite the right sound".
Instead, the noise that Audi has come up with is purely electronic, developed using computers and keyboards. While nothing like a regular engine noise, these tones do have a certain personality to them.
"When you compose music or sounds, you have to be true to your convictions," Halbmeir says. "A cars sound is similar to music ... the moment you cut corners, you essentially end up with elevator music."
Other makers have their own unique sounds to warn pedestrians, including a low gurgle from Volkswagen's electric Golf (which has been compared to a Wookiee from Star Wars), a buzzy whirr of Renault's Fluence ZE, through to high-pitched whistle from Nissan's Leaf.
What sounds electric cars should make is being currently debated, with some brands unwilling to create synthetic sounds.