In the case of Audi->ke14, it involves a few compromises. In this video, Audi talks about the challenges of producing that emotional sound supercar owners love on a car that's run by electricity. The solution, as far as Audi engineers are concerned, was to develop a synthetic sound signature that can be played with a loudspeaker attached to the car's undercarriage.
Take note of the word "synthetic" because that in itself means that the sound is fabricated and not directly derived from the engine. Nevertheless, the objective with the "E-Sound" was to generate enough noise to allow drivers to enjoy the thrills of a supercar with an electric powertrain.
Check out the videos - one of which you can find after the jump - to find out how Audi accomplished giving the Audi R8 E-Tron the supercar-like sounds similar to its gasoline-powered siblings.