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case studies → city noise management

The city council of Zurich subsequently focused its attention on noise of civilization and considers the topic a strategic focus. It turned out, that the issue of noise (apart from well-known noise sources such as clubs and bars) has not yet been analyzed. To determine the potential and identify methods to reduce overall noise footprints within the city of Zurich, the municipality has commissioned us to examine Zurich’s nightlife hotspot at Langstrasse.

it is all about those reflections

Our simulations unveiled, that most of the sound we hear in urban environments is a mutual reaction of predominantly traffic noise and amplified speech. Furthermore, sound is reflected multiple times by walls as cities typically have very little natural damping (e.g. trees) and diffusion (e.g. absorbing building walls). A careful combination of small measures can reduce overall noise level by more than 50 percent. Small variations make a great difference in performance.

Simulation of building reflections in a city.

Integrating acoustic expertise into urban planning contributes to the reduction of conflicts about noise and the negative impacts on health arising from noise. Due to the fact, that most of the sound reaching our ears in cities originates from reflections, acoustic designs of the cities are possible and should be integrated early in the process of urban planning.

See our report as published by the city of Zurich (in German).

Und .. selbstverständlich sprechen wir Deutsch und bedienen unsere Kunden in der Schweiz und Deutschland in der entsprechenden Landessprache. Wir freuen uns von Ihnen zu hören!

low frequencies – same, but different

Because of their wavelengths, low frequencies behave differently compared to high frequencies when propagating. Low frequencies bend around objects, resonate between walls and interferences occur. Yet typical simulation tools simulate the entire frequency spectrum with applied ray tracing, which simplify sound waves as rays traveling in straight paths (similar to light). This results in quite accurate predictions for the propagation of high frequencies, but a significant inaccuracy for low frequencies.

A BEM (boundary element method) simulation of city buildings at 60 Hertz.

We have developed our proprietary simulation toolchain targeted specifically at low frequencies. As one can see in the above image, such simulations e.g. considers reflections and shows the different sound pressure levels reached within allies throughout an entire city block. In the end, such simulations aid profound understanding of the situation at hand. In the case of Zurich, our customer is able to take both small and large educated decisions: judging noise complaints, allowing night club permits or respecting noise in urban planning.

Do you face a similar challenge? Get in touch with us and let us help.

Read more about our work in our other case studies.