New-Tech Europe Magazine | February 2018

board in a sound studio. Its controls are used to create a synthetic sound which is then processed and adapted according to the results of listening tests conducted with human subjects. In addition to frequency range and timbre there are several other particularly important properties when it comes to automotive sound design, for example roughness. Roughness is determined by the speed of changes in a sound’s volume. Particular roughness is created when the volume changes something like 50 to 70 times per second. “Roughness in a sound is perceived as especially sporty,” Fastl explains. “A Ferrari without roughness would be very hard to sell.” Loud, But Not Too Loud Special interior sounds are being designed for e-vehicles as well, even though there are no applicable regulations. The actual sound created by an electric motor could remind the driver of a tram; the interior sounds are tailored to the right target group just as the external sounds are. “Anyone who drives a 7 Series BMW will want to have peace and quiet,” Fastl points out. “On the other hand Porsche drivers will want to be able to hear their investment at work.” And presumably pedestrians and those living and working close to streets don’t want to be overwhelmed by traffic noise. “For 20 years the objective has always been to make cars quieter,” says Fastl. “Now things are in part too quiet and we have to get louder again.” Nevertheless, Fastl advises against doing away with all the advantages of the low-noise electric vehicle: “More and more cars with automatic pedestrian detection will be coming onto the market. We recommend that the e-vehicle only transmit sounds when a pedestrian is in the vicinity.”

You can play the first notes of a Mozart symphony on a smartphone in such a way that everyone recognizes the melody,” says Fastl. “But it doesn’t sound so great. When the same notes are played by a chamber orchestra with ten musicians, it sounds much better. And a full orchestra with 50 people can play the music to sound just the way the composer intended it to sound.” Nevertheless, Fastl and his team don’t work with an orchestra, they generate the timbre of the sounds on the computer. Here they use a sound “construction kit” which they conceived and programmed themselves to develop target group-specific sounds. “It’s a computer that can generate a wide range of sounds for use as ingredients, based on algorithms we developed ourselves.” The sound machine resembles a mixing

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