Localization and Identification Of moving Noise sources (LION)
Sound source localisation methods are widely used in the automotive, railway, and aircraft industries. Many different methods are available for the analysis of sound sources at rest. However, methods for the analysis of moving sound sources still suffer from the complexities introduced by the Doppler frequency shift, the relatively short measuring times, and propagation effects in the atmosphere. The project LION combines the expertise of four research groups from three countries working in the field of sound source localisation: The Beuth Hochschule für Technik Berlin (Beuth), the Turbomachineryand Thermoacoustics chair at TU-Berlin (TUB), the Acoustic Research Institute (ARI) of the Austrian Academy of Sciences in Vienna and the Swiss laboratory for Acoustics / Noise Control of EMPA. The mentioned institutions cooperate to improve and extend the existing methods for the analysis of moving sound sources. They want to increase the dynamic range, the spatial, and the frequency resolution of the methods and apply them to complex problems like the analysis of tonal sources with strong directivities or coherent and spatially distributed sound sources. The partners want to jointly develop and validate these methods, exploiting the synergy effects that arise from such a partnership. Beuth plans to extend the equivalent source method in frequency domain to moving sources located in a halfspace, taking into account the influence of the ground and sound propagation through an inhomogeneous atmosphere. ARI contributes acoustic holography, principal component analysis, and independent component analysis methods and wants to use its experience with pass-by measurements for trains to improve numerical boundary element methods including the transformation from fixed to moving coordinates. TUB develops optimization methods and model based approaches for moving sound sources and will contribute its data base of fly-over measurements with large microphone arrays as test cases. EMPA contributes a sound propagation model based on TimeVariant Digital Filters with particular consideration of turbulence and ground effects and will also generate synthetic test cases for the validation of sound source localization algorithms. The project is planned for a period of three years. The work program is organized in four work packages: 1) the development of algorithms and methods, 2) the development of a virtual test environment for the methods, 3) the simulation of virtual test cases, and 4) the application of the new methods to existing test cases of microphone array measurements of trains and aircraft.
Contact: Jean Marc Wunderli
Funding: SNF (Lead Agency Project)
Duration: 2020 - 2023

Man - made elastic structures (often referred to as metastructures) are promising in applications where filtering, focusing or channeling of elastic waves is required. Few examples encompassing different length scales include shielding of buildings from seismic waves, enhanced damping of undesired vibrations of industrial machinery, frequency up-conversion or down-conversion.  However, as we head towards metastructure's massproduction, some important limitations associated with their modelling need to be addressed.  In fact, current models of their dynamic response mainly rely on structural periodicity and bulk behavior. The first and main goal of this project is to develop efficient and accurate FEM algorithms able to predict the dynamic response of non-periodic metastructures, embedded into hosting elastic materials.  The second objective of the project is to validate those simulation tools on the dynamic response of aperiodic metastructures, whose tiling involves two or more overlapping periodicities. We envisage the use of (I) model-order-reduction techniques - to mitigate the numerical demand of the proposed metastructures (complex geometries, irregular boundaries) - and (II) topological optimization techniques - to achieve desired dynamic properties. The proposed materials-by-designs will finally be tested experimentally using 3D-printed prototypes.
Contact: Bart Van Damme
Funding:  EMPA
Duration: 2019 – 2021

Data Science Enabled Acoustic Design – AADS
Project description:
Contact: Kurt Heutschi
Funding: Swiss Data Science Center
Partner: Swiss Data Science Center, Gramazio Kohler Research - ETH Zürich, Strauss Electroakoustik
Duration: 2018-2020

OSCAr: Acoustically optimized street canyons
Street canyons in urban areas with a high building density exhibit challenging acoustic environments for the residents and passerby. The multiple sound reflections between the opposite facades not only enhance the noise level and consequently noise annoyance, but can also impair speech intelligibility and acoustic comfort.  
Mandated by the Federal Office for the Environment FOEN, Empa is investigating the acoustic quality in street canyons. Thereby, various building arrangements and facades are being simulated. By means of laboratory experiments (i.e. listening tests) it will be investigated and quantified to what extent the building geometry, as well as the facade structure and absorption, influence noise annoyance and acoustic comfort.
Contact: Kurt Eggenschwiler
Partner/Funding: FOEN
Duration: 2019 – 2020

Urban Mining for Low Noise Urban Roads and Optimized Design of Street Canyons
The soundscape of urban situations is often dominated by road traffic noise. In densely populated areas, noise can cause serious health problems and therefore, city planners are seeking for suitable design strategies to improve the acoustical quality of public spaces.
This SNF funded project aims for a multidisciplinary approach to optimize urban roads and street canyon designs. It is structured in four modules:
1) Development of low noise pavements to improve comfort and health of urban dwellers.
2) Identification of waste materials from the urban environment, for the purpose of producing low noise pavements.
3) Exploration of the noise reduction potential by modification of absorption and reflection properties of the surfaces that form urban street canyons and evaluation of the measures from a subjective point of view by auralisation and listening tests.
4) Improvement and extension of existing methods in Life Cycle Impact Assessment based on the results obtained in module 3).
Contact: Kurt Heutschi
Partner/Funding: Empa Road Engineering / Sealing Components Laboratory, ETHZ Ecological Systems Design, SNF
Duration: 2018 – 2021

Implementation of a pilot assisting system for low noise landing procedures at Zurich Airport
This project aims at further developing the pilot assistance system LNAS of the German Aerospace Center DLR, to allow different types of approaches such as Continuous Descent Approach (CDA) respecting the specific environment of Zurich airport (terrain, airspace restrictions, etc.). Taking into account the pilots user requirements, the human-machine interface shall be improved for an intuitive display of the aircraft configuration change and flight mode commands on an approach map. Additionally, the ATC information about the distance to threshold shall be used to optimize the vertical flight profile. In a one-week flight campaign the system will be demonstrated using the DLR Airbus A320 ATRA (Advanced Technology Research Aircraft) with regular airline pilots operating in the Zurich airport environment to reduce noise with optimized approach profiles and aircraft configuration changes. Noise measurements and subsequent single flight simulations with sonAIR based on FDR data will be conducted by EMPA to analyze the potential of this pilot assistance system. An operational trial with LNAS on aircrafts of Swiss Airline and related 3-month noise measurements is an option of this project.  Industrialization of LNAS is the long-term goal after successful demonstration.
Contact: Jean Marc Wunderli
Partner/Funding: SkyLab, DLR, Zurich Airport, skyguide, Swiss Airlines, Swiss Air Force / FOCA, Office of Transport of the Canton of Zurich (AFV)
Duration: 2018 – 2020
SRF-Beitrag "Schweiz aktuell" vom 10.9.2019

BiMeWAVES aims to develop a new class of innovative materials capable of controlling acoustic and elastic waves by adapting the concept of hierarchical structure derived from biological systems to a new class of artificially engineered media, i.e. the so-called elastic Metamaterials (MMs).
The project integrates inter-disciplinary aspects such as: (1) biological inspiration driving the (2) design, manufacturing and optimization of innovative materials guiding the conclusive (3) proof-of-concept experiments aimed at providing the society with novel applicative tools in diverse technological fields, ranging from noise abatement to non-destructive evaluation and underwater acoustics.
Contact: Armin Zemp
Funding: Marie Curie COFUND
Duration: 2018 – 2020

Currently the Federal Noise Abatement Commission discusses in the context of a harmonization of noise abatement and land-use planning regulations the following questions: Are negative effects of traffic noise reduced in the presence of local recreational areas? If yes, could an installation or upgrading of such recreational areas be seen as a noise mitigation measure?
FOEN advised Empa to investigate these questions by reanalysing the survey sample dataset of the SiRENE study. To that purpose additional information on general properties, distance and accessibility of recreational areas should be collected and combined with the present dataset.
Contact: Jean Marc Wunderli
Partner/Funding: FOEN
Duration: 2018 – 2019

Mandated by FOEN, Empa is trying to elucidate the role of single noise events and quiet interim phases on annoyance, based on unfocussed listening tests. The results shall be used to discuss whether future rating levels for traffic noise shall solely rely on average levels such as Leq or if they should be complemented by additional correction factors like the number of pass-bys.
Contact: Jean Marc Wunderli
Partner/Funding: FOEN
Duration: 2018 – 2019

Acoustic Characterization of fungi-treated Violins
How does a fungi-treatment of the tone-wood affect the acoustic properties of violins? An experimental investigation of the structure-borne and the radiated sound fields of different violins – treated and untreated – is performed in the anechoic laboratories. A subsequent psycho-acoustic investigation focusses on the perception and endeavors to single out significant acoustic properties of the individual instruments.
Contact: Armin Zemp
Partner/Funding: Fischli-Stiftung, Allschwil, CH
Duration: 2017 – 2019

Towards Noise and Weight Reduction by Application of FRP Wheelsets for Freight Wagons
Fiber-reinforced polymer (FRP) composite materials shall be used to manufacture a train wheelset which will generate less noise and leads to a significant weight reduction of the wheelset. The technical feasibility is verified in this project in collaboration with our partners.
Contact: Armin Zemp
Partners: Laboratory for Structural Engineering (Empa), Carbo-Link, PROSE AG
Funding: FOEN
Duration: 2017 – 2018

Novel Rail Pads for Improved Noise Reduction and Reduced Track Maintenance
The goal of the project is to develop a novel rail pad system that is optimized with respect to both railway noise reduction and protection of the railway superstructure against transient loads and vibrations. The desired property profile of the novel rail pad cannot be obtained with existing materials, but requires tailoring of the structure and function of the rail pad system at multiple levels and length scales.
We will complement experimental methods with state-of-the-art modelling in order, for the first time, to establish rigorous structure-property relationships, and provide detailed guidelines for combined materials selection and device geometry optimization.
Contact: Armin Zemp
Partners: École polytechnique fédérale de Lausanne EPFL (LMOM, LPAC, LMAF, LTS2, TRACE), SBB
Funding: FOEN
Duration Phase I: 2017 – 2019

Validation of the aircraft noise simulation model sonAIR
Validation of the aircraft noise simulation model sonAIR based on measurement data, which was not used in the model development. To that purpose also measurement data from external partners will be used. In addition some open issues of the initial project phase will be studied in more detail.  
Contact: Jean Marc Wunderli
Partner: Swiss International Airlines, DLR, TU Delft
Project funding: FOCA
Duration: 2017 – 2018

Estimation of flight parameters based on radar data
Besides position, orientation and speed, the sonAIR sound source models also needs information on thrust setting and configuration as input parameters. However this information is generally not available. Therefore methods shall be developed on how to estimate aircraft mass, thrust setting and configuration based on radar data. On that basis the range of applications of sonAIR can be substantially extended and will allow to calculate entire airport scenarios in the future.
Contact: Jean Marc Wunderli
Partner: Swiss International Airlines
Project funding: FOCA
Duration: 2017 – 2018

Development and operation of a monitoring system for aircraft noise for the specific demands of sonAIR
In this project a mobile monitoring system together with an automized analysis system shall be developed with the goal of regularly updating the emission database of sonAIR. The monitoring system shall then be used to derive sound source models for recently introduced and modified aircraft types of Swiss International Airlines, such as Bombardier C-Series, Boeing B777 and the modified Airbus A320-family.
Contact: Jean Marc Wunderli
Partner: Swiss International Airlines, skyguide
Project funding: FOCA
Duration: 2017 – 2019

IDeAL (Impact Driven Assessment of novel Low-noise aircraft concepts) Pilot study
The goal of the IDeAL project is to optimize novel low-noise aircraft concepts and alternative flight procedures with respect to human perception and annoyance.  
The simulation and development of aircraft concepts and flight procedures is done by the German Aerospace Centre (DLR). Its results provide the necessary inputs for auralizations done by Empa. Based on listening tests perceived loudness and annoyance shall be evaluated and used as a feedback-loop to optimize the design. In this pilot study a proof of concept, an identification of open research questions as well as an assessment of the existing optimization potential shall be accomplished.
Contact: Reto Pieren
Project partners: DLR
Project funding: BAFU
Duration: 2017 – 2018
Available Publication


ARTEM - Aircraft noise Reduction Technologies and related Environmental iMpact
With ARTEM (Aircraft noise Reduction Technologies and related Environmental iMpact), seven EREA members and strategic partners have teamed up with leading European universities and major entities of the European aerospace industry in order to address the technology challenges raised in the call MG-1-2-2017 “Reducing aviation noise”. ARTEM aims at the maturing of promising novel concepts and methods which are directly coupled to new low noise and disruptive 2035 and 2050 aircraft configurations. A core topic of ARTEM is the development of innovative technologies for the reduction of aircraft noise at the source. The approach chosen moves beyond the reduction of isolated sources as pure fan or landing gear noise and addresses the interaction of various components and sources - which often contributes significantly to the overall noise emission of the aircraft. Secondly, ARTEM addresses innovative concepts for the efficient damping of engine noise and other sources by the investigation of dissipative surface materials and liners. The chosen technology concepts offer the chance to overcome shortcomings (as the narrow band absorption peak or poor low-frequency performance) of current devices. The tasks proposed will mature, and subsequently down select these technologies by comparative testing in a single relevant test setup. Furthermore, noise shielding potential for future aircraft configurations will be investigated. The noise reduction technologies will be coupled to the modelling of future aircraft configurations as the blended wing body (BWB) and other innovative concepts with integrated engines and distributed electrical propulsion. The impact of those new configurations with low noise technology will be assessed in several ways including industry tools, airport scenario predictions, and auralization. Thereby, ARTEM constitutes a holistic approach for noise reduction for future aircrafts and provides enablers for the expected further increase of air traffic.
Contact: Jean Marc Wunderli
Project partners: DLR, AEDS, Airbus, CIRA, CNRS, Comoti, Dassault, EC Lyon, EPFL, ONERA, INCAS, PPS, RRD, SAE, SOTON, TSAGI, TUBS, TUDelft, UBristol, UCP, URoma3, VKI
Project funding: EU – Horizon 2020
Duration: 2017 – 2021

TraNQuIL - Transportation Noise: Quantitative Methods for Investigating Acute and Long term health effects
The overall aim of TraNQuIL is to obtain a thorough understanding on how transportation noise affects human health. In particular, the following research questions will be addressed:

  1. How relevant is eventfulness of noise and duration of quiet phases between events for cardiovascular mortality, and adolescents’ cognitive performance, behaviour and quality of life?
  2. How crucial is noise exposure at different times during day and night for these outcomes?
  3. How relevant is noise exposure at home vs. school for adolescents’ cognitive performance, behaviour and quality of life?
  4. Are noise induced cardiovascular risks reversible after noise exposure reduction? If yes, what is the relevant time scale?
  5. Do noise events trigger an acute cardiovascular death?

Research will be based on the existing Swiss National Cohort (SNC) and adolescent HERMES cohort study. Nationwide models for road, railway and aircraft traffic noise as well as NO2 exposure at each address in Switzerland for 2001 and 2011 will be individually linked to study participants. For HERMES participants, a longitudinal analysis will be conducted to evaluate the effects of noise exposure at school and home on changes in cognitive function, behaviour and health related quality of life within one year of follow-up. Full residential history available after 2010 for the SNC will be used to elucidate the effects of a sudden change of exposure on cardiovascular mortality. A case-crossover analysis on the triggering effects of aircraft noise on acute coronary events in the population around Zürich airport will be conducted, taking advantage of the daily distribution and variation of noise exposure which is heavily influenced by meteorological conditions.
Contact: Beat Schäffer
Project partners: Swiss TPH
Project funding: Swiss National Science Foundation
Duration: 2017 – 2021

Noise Protection in Wooden Buildings
Complaints about noise intrusion from neighboring dwellings, especially from people walking, are still a major problem in multi-family wooden buildings.  The goal of the project “Noise Protection in Wooden Buildings” lead by Lignum and in collaboration with Empa and the Bern University of Applied Sciences is to improve acoustic comfort in modern multi-family wooden buildings in Switzerland by generating knowledge on the airborne and impact sound insulation and disseminating it for the engineers and planers.  The role of Empa’s Laboratory of Acoustics/Noise Control within this project is the experimental investigation of sound transmission through building elements and in mock-ups of typical Swiss wooden buildings in the lightweight construction sound transmission research platform and the analysis of the data. Further, Empa post-processes the data for the use as input data for engineering models for the prediction and optimization of airborne and impact sound insulation. Empa derived simplified engineering models from prediction models for heavy construction, such as concrete and masonry that are well established in Europe. These models can be applied by practitioners and engi-neers already in the stage of design of wooden buildings. The project is funded by the “Aktionsplan Holz” of the Swiss Federal Office of the Environment (FOEN) and a consortium of industry partners.
Contact: Stefan Schoenwald
Project partners: Lignum, BFH-AHB, Industriepartner
Project funding: Lignum
Duration: 2016 – 2018

Under the umbrella of the European Shift2Rail initiative to support research and innovation in rail product solutions, the project DESTINATE aims to develop tools and methodologies for railway noise simulation and cost-benefit analysis of mitigation actions of interior and exterior noise. Empa is involved in the auralisation and visualization of noise mitigation measures with the goal to more accurately predict peoples response to exterior noise from a residents perspective and to interior noise from a passengers perspective.
Contact: Kurt Heutschi
Project partners: Technische Universität Berlin (Coordinator), TUB, Germany, Politechnika Poznańska, PUT, Poland, University of Newcastle upon Tyne, UNEW, UK, Müller-BBM GmbH, MBBM, Germany, Sound Advice in Technology, Innovation and Strategy, SATIS, The Netherlands, Stadler Rail Valencia, STAV, Spain, Netherlands Aerospace Centre, NLR, The Netherlands
Project funding: EU Horizon 2020
Duration: 2016-2018
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Coating of freight wagons for noise mitigation
The goal of this project is to assess the effectiveness of a coating applied to freight wagons for noise mitigation. Besides the sensitivity of the coating material to wear, the impact on the vibratory response of the silo before and after coating as well as the reduction of the noise emission during loading and draining of gravel are experimentally investigated.
Contact: Armin Zemp
Project Partner: Josef Meyer Rail
Project Funding: FOEN
Duration: 2016 - 2017

The Sound of Brass: The Materiality, acoustics and history of brass instruments, based on the example of historically informed replica of German trombones
How were early brass instruments constructed, and of what? If we build copies using historic manufacturing techniques, what impact does this have on their playing characteristics and their sound? And can we measure this?
Many questions on the materiality and the production technology of historical brass instruments remain unanswered today. This project is intended to use reconstructions of the legendary German trombones of the 19th and early 20th centuries to reacquire the techniques of historical craftsmen. The acousticians of Empa are investigating their influence on the playing characteristics and on the radiated sound. The reconstructions of German orchestral trombones built in the course of this applied research will ultimately be presented in concert.
Contact: Armin Zemp
Project Funding: CTI
Duration: 2015–2018

Dr. Jean-Marc Wunderli

Dr. Jean-Marc Wunderli
Head of Lab Acoustics/Noise Control

Phone: +41 58 765 4748

Dr. Reto Pieren

Dr. Reto Pieren
Head of Group Environmental Acoustics

Phone: +41 58 765 6031

Dr. Armin Zemp

Dr. Armin Zemp
Head of Group Materials & Systems

Phone: +41 58 765 4527