Audi is driving out the last creaks, cracks and rattles from its cars courtesy of a dedicated "noise team". During the development of every new Audi model, innumerable tests on the road and on test rigs are carried out until the last "creaking and cracking" problems are silenced - another example of Vorsprung durch Technik.
The "noise team’s" task is not merely to eliminate noises that really cannot be ignored but to get rid of those that irritatingly only appear when certain road surface conditions, temperatures, speeds or distances are encountered or driven.
Eckhard "The Ear" Peithmann heads Audi’s "noise team" and admits that it can often be a slow, drawn out affair. He says: "This job calls for a sensitive ear but also a great deal of patience. Some noises can only be heard after the umpteenth test. This work can’t be taught at school or during a training course and can severely test an individual’s patience - the work is not to everyone’s taste."
Detecting all those sources of noise is a costly and time-consuming affair. Noise analysis for any particular Audi model takes an entire year. Every four to six weeks, members of the team begin another test drive. Either in the bitter cold on test routes in Scandinavia or on desert tracks in North Africa. Depending on the complexity of the task, each of these outings may last between six and 12 days.
Additionally, noise is analysed on roller and shaker test rigs, in climatic chambers, with dummy-head microphones and on a hydro pulse facility at Audi’s technical development centre in Ingolstadt, Germany.
Carsten Vortanz, a member of the "noise team’s" steering committee, confirmed: "During winter near the Artic Circle, the temperature drops as low as minus 40 degrees Centigrade.
At that level, plastics lose some of their elasticity, their friction coefficients alter and they are therefore more prone to produce noise. Likewise their properties also change when exposed to severe heat which is why we test in North Africa for example."
Moving parts in particular are liable to generate noise. Seats, doors, seals and glove compartments plus squeaky leather can give the testers the kind of earache they would sooner avoid. A fault evaluation key has been drawn up for all materials and components, with all noise defects recorded.
Over the years, the "noise team" has compiled a "creaking and cracking catalogue" which serves Audi engineers with a basis when developing a new model in order to avoid designs with unwanted "noise potential" from the very start. The experts can even identify certain sources of noise when looking at the design of a digital model on a computer screen - well before any actual hardware which might crack, rattle, clatter or squeak is even produced.
Audi is an international developer and manufacturer of high-quality cars. In 2001, the company sold more than 726,000 Audi models. The revenue of the Audi Group totalled around EUR 22 billion last year. The Audi Group has more than 50,000 employees.Published 30 July 2002