"FensterKlang" - Contributing to the personalized selection of windows by making sound insulation audible

How do windows sound?

Windows play a key role in the design of a façade. They reduce the amount of sound entering the building. Selecting windows with the “right level” of sound insulation is particularly important when it comes to personal sound protection. However, until now it has not been possible to take into account what sound insulation actually sounds like under exposure to different types of noise. The aim of the “FensterKlang” project worked on by the Performance Center Mass Personalization is therefore to build a digital tool for listening to the sound insulation of windows, enabling different sound scenarios to be considered so that windows can be chosen in a more extended and personalized way.


Highlight of the Performance Center

online tool for making the sound insulation of windows audible
© Fraunhofer IBP
View of the online tool for making the sound insulation of windows audible: After entering the calibration (listening volume), target size and sound profile, three windows are automatically selected from a database and compared. Two diagrams show the frequency-dependent sound reduction indexes (left) and sound pressure levels (right) for each proposed window.

The sound reduction index is calculated on the basis of frequency-dependent measurement results. A standardized reference curve is used to determine a single-number value Rw for classification into sound insulation classes. The extent to which the subjectively perceived frequency-dependent sound insulation of the window is suitable for achieving the best possible sound insulation in the on-site noise situation can only be determined to a limited extent on the basis of the single-number value.

The aim of the project is thus to make the sound reduction index audible as a criterion for personal selection and product development before new windows are installed. Finally, the potential of this method is demonstrated by implementing a prototype in the form of a digital tool. This allows people even without acoustics skills to subjectively evaluate the sound insulation.

"FensterKlang" is designed to specifically reduce the noise load on the population as well as to ensure that new windows are selected cost-effectively and sustainably. This makes it easier to choose windows that take into account situation-dependent noise emissions and personal, subjective perceptions.

In addition, window designs can be matched in a more differentiated and situation-related manner. Heat pumps, for example, have rotating elements that can generate tonal and thus disturbing noise. By specifically matching windows with the methodical approach, building on "FensterKlang", the technical development of the industry can be promoted in an interdisciplinary way and the best possible noise control can be achieved for the case in question.

Fraunhofer IBP also develops further target and evaluation parameters based on objective and perception-driven noise analyses. The subject area of psychoacoustics forms the basis for this, which has already been used for many years, for example in the automotive industry, in product development.

This has resulted in scientific consulting and support services for the industry, which benefits from established approaches to innovative product development in the context of building acoustics. Professional perception studies with test persons round off this consulting and development service in a target-oriented manner.

The “FensterKlang” concept can be used to extend acoustic tests on building components on the basis of measurements. Fraunhofer IBP's accredited test laboratory for building acoustics and noise immission control has several acoustics laboratories, such as a test facility for measuring the sound insulation of windows. Extending the results of laboratory measurements for evaluating the acoustics of components in and on buildings to include subjective, perception-related parameters brings together experts in building acoustics, room acoustics and psychoacoustics at Fraunhofer IBP on an interdisciplinary basis. You benefit enormously from our many years of experience in acoustic measurement technologies, their application in accordance with relevant standards, as well as the planning, implementation and statistical evaluation of perception studies.