The Story: Car sounds
In 1997, the Rover car manufacturer developed a new, attractive, and well-functioning Rover car model. The only problem was that the power assisted steering generated an unpleasant sound when in the outermost positions. This had to be dealt with to ensure customer satisfaction.
A prototype for the new Rover model was secretly shipped to Denmark. In Denmark, DELTA was waiting to carry out what is known as ‘artificial head recordings’ (a method where the sound is recorded by stereo recording techniques similar to how a person would hear the sound) of the sound from different versions of the car’s power steering parts. DELTA used the artificial head recordings to carry out listening tests, where listeners assessed to what degree the power steering sounds were acceptable.
Codan Rubber, who delivered the components to the servo control system, used the results from the listening tests to localise the jarring sounds and move the components around, to change the sound. A small and quirky engineering task. In a short time, the servo control system sounded fine, and the car subsequently received excellent recommendations in car magazines.
Focus on the user’s perception of the sound
Today the design of car sounds is a widespread practice among manufacturers, who have acknowledged the importance of how car sounds are perceived by the users. For example, DELTA has helped Volvo design interactive sounds in cars, so that the sounds have the optimal functionality and sound quality. In addition, DELTA has set up sound profiles in a sound hierarchy, which Volvo can use to design sounds with, so that sounds are intuitive for the users.
The term Perceptual Based Design focuses on designing sounds with people at the centre and in the context in which the sound is generated – as opposed to looking at the sound’s physical properties. Interestingly, perception and assessment of sound depends partly on the context in which the sound occurs, and partly on the people experiencing the sound.