The good news for designers and drivers is that tools exist to mitigate these auditory irritants. Better yet, development teams at automakers are increasingly familiar with them. During the past few decades, vehicle manufacturers have become more comfortable in applying acoustic simulation software to pinpoint potential noisemakers, and they do so long before the design of body panels is finalized and construction of confirmation prototypes is kicked off. This has had a positive effect on sound within the vehicle, allowing noise troubleshooting to concentrate more on manufacturing issues, not to mention significantly reducing hardware prototyping costs and development times.
With acoustic simulation tools, automotive engineers can develop virtual twins of their designs, simulating the many acoustic signatures, then quickly identify and mitigate any over-target noise. Simulations can be repeated until the vehicle design is as quiet as desired.
It wasn't always like this. Before advanced simulation processes became available, automakers were forced to make educated guesses about the sources of vehicle noise and then proceed with building physical mock-ups to assess their status. In addition to the cost of multiple stages of prototype construction, development teams had to be concerned with the accuracy of their physical mock-ups as designs continually evolved. For instance, a full-scale clay model with a simulated front side glass and truncated cabin space could rapidly become obsolete for assessing wind noise as the size and shape of the glass panel was redesigned.
Such specialized physical mock-ups were also limited in the range of design changes that could be recommended because wind noise can enter the cabin through many paths, such as underbody panels and door seals. This was clearly a cumbersome approach. With decreasing timelines for development, as well as the expanding number of models to be released, evaluating noise fixes via physical models became ever more impractical due to the cost and the time needed to build them.
Wind noise is just one example. There was also the sound of the combustion engine, exhaust and intake, plus noise from the tire contact patches. In the pre-simulation world, each of these required expensive hardware prototypes and often, dedicated laboratory facilities and personnel to attempt noise refinement as best as possible. Extreme stress was experienced near program launch dates by teams whose subsystems were not meeting noise targets. Thankfully, improved acoustic simulation processes have allowed launch pressures to be directed at refining more subtle noise issues.