About the lab
The Building Acoustics group of TU/e focuses on research in the field of Acoustics of the Built Environment. Look here www.tue.nl/buildingacoustics for an overview.
Featured projects (5)
When designing concert halls and theaters, providing excellent stage environments is an acoustic challenge. For centuries, acousticians have been focusing on the acoustics in the hall from an audience point of view. The past decades, also the importance of acoustic comfort for musicians on the stage is recognized. Good stage acoustics is important for the orchestra to easily play together and to avoid hearing damage caused by excessively high sound pressure levels. Up to 74% of the professional musicians suffer from hearing disorders, which is a major health problem. So far, few solutions have proven valid that can prevent hearing damage to musicians and at the same time improve the ease of playing together by orchestra members. Moreover, just a few satisfying correlations have been found between the musician’s judgment of stage environments and stage acoustic parameters. To be able to better understand the musicians’ demands for acoustic comfort on stage more research is necessary. The aim of this project is to improve the objective measurement and prediction methods to assess the influence of architectural measures on stage acoustic parameters and musicians’ noise exposure. For the first time, the influence of the orchestra is taken into account. The final result is a measurement and prediction method as well as guidelines that can be used by researchers and engineers when designing stage environments. The final goal is to improve acoustic comfort for musicians in concert halls and theaters from a musical as well as a health point of view
Urban sound planning is often insufficiently considered in urban planning, resulting in unsatisfactory urban sonic environments. It is widely accepted that the acoustic comfort within the cities should aim for more than just preventing and controlling excess noise exposure. It should instead support the wellbeing and health of residents. SONORUS – the urban sound planner project, a European Integrated Training Network (ITN), is trying to overcome this restriction by developing a new, holistic approach. To know more about this project check the project's website : http://www.fp7sonorus.eu/ or the student's blog: https://sonorusfp7.wordpress.com/
Acoutect is an European training network that has received funding from the European Union’s Horizon 2020 under the Marie Skłodowska-Curie action (H2020-MSCA-ITN-2016). Acoutect marries “Acoustics” and “Architect” and responds to the important role that Acousticians have in the design of modern buildings. The Acoutect consortium is composed of top universities, research institutions and companies in various disciplines and sectors of building acoustics and beyond.
Featured research (9)
Reliable data on acoustical properties of materials are crucial for the design of a desired acoustic environment as well as to obtain accurate results from acoustic simulations. Although the acoustical properties of materials can be obtained via laboratory measurements, situations where in situ measurements are needed are often encountered. However, in situ measurement methods presented so far are limited by their poor portability or inaccuracies in the low-frequency range. In this work, we propose a characterization method that combines an in situ pressure-velocity (PU) measurement with a model fitting procedure using the Delany-Bazley-Miki impedance model for porous materials. The method uses an optimization routine to find the best match of measured and modelled reflection coefficient values within a given frequency range for the optimization parameters: flow resistivity, panel thickness, and probe-sample distance. The optimal parameter values allow, in turn, calculating the porous panel’s reflection coefficients for a broad frequency range including frequencies below the lower bounds of the optimization frequency range. The sensitivity of the method to panel width, lower bound of fitting frequency range, and to excluding parasitic reflections by time windowing is studied. The study shows that the proposed method provides characterization results in good agreement with reference data for panels of dimensions larger than 1800 mm and that the method is robust for reduction of one dimension of the panel down to 300 mm. It also shows that the model fitting accuracy is best when the frequency range of analysis is restricted to 1000–5000 Hz.
The in situ characterization of acoustic surfaces is a crucial challenge in room acoustics, as laboratory measurements of mounted materials are difficult to arrange. In previous work, an approach to characterize locally reacting porous samples backed by a hard wall was studied and showed good accuracy. However, when a porous layer is backed by a large air cavity (depth > 100 mm), a configuration typically found in suspended ceilings, the air cavity features a non-locally reacting behaviour; thus the local reaction cannot be assumed safely. This work presents a procedure to characterize such a non-locally reacting system by in situ PU probe measurements, where the non-acoustical parameters of the system are retrieved by a model fitting approach comparing the measured complex reflection coefficient to the one of a porous layer without backing. The procedure was applied to 9 combinations of 3 porous layers backed by 3 air cavity depths each. A good agreement was observed between the retrieved parameters and references values.
Noise barriers reduce the level of noise that reaches the receiver by interrupting the noise propagation path. Even though noise barriers are effective at high frequencies, low-frequency control remains challenging as sound waves at low frequencies are easily diffracted over the barriers. In this work, we show that by designing noise barriers designed with an array of tuned resonators can achieve high attenuation, more than 5 dB, of noise at low frequencies. The propagation of low-frequency waves is significantly suppressed by the interplay of the tuned resonators installed on the surface of the noise barriers. Analytical models and numerical simulations are used to calculate the insertion loss by the designed noise barriers.
In this work, vibrations of complex structures excited by an impact source are modelled using the time domain nodal discontinuous Galerkin (DG) method, which solves linear elasticity equations. Two structures of interest, a T-shaped structure and a scaled lightweight wooden floor (LWF), are taken as example cases. Both structures consist of components that differ in their mechanical properties. Rankine-Hugoniot jump conditions for piecewise constant material properties are used to obtain accurate numerical fluxes in the DG method. Free or fixed boundary conditions are imposed on the surfaces of the structures. Furthermore, constant viscous damping forces are added to the model to create vibrational energy losses of the structure. To validate the numerical results, the mobility of the structures is calculated and compared with experimental data. The agreement is good regarding the natural frequencies, with a maximum difference of less than 4 % for the T-shaped structure in the range below 500 Hz, and 6.4 % for the scaled LWF in the range below 300 Hz. The adopted damping approach is shown to be insufficient to represent a broad frequency range.
In order to support acoustic consultants in providing tailored solutions to clients regarding facade insulation against environmental noise, a subjective method has been designed to assess the effect of four types of facade solutions by using acoustic virtual reality. In this exploratory study, environmental traffic noise was recorded in first-order Ambisonics inside an apartment of which the facade is exposed to road traffic noise, and simultaneously a 360-degree picture was captured. For a listening experiment, the measured indoor audio stimuli were filtered according to spectral changes corresponding to four facade insulation intervention scenarios. To test the effect of environmental noise on noise annoyance and performance, a within-subject experiment with n=10 participants was designed containing ISO/TS 15666 questions and a Rey auditory verbal learning task (ReyT). Both tasks were carried out in a VR environment, which consisted of a head-mounted display and headphones. The subjective results showed a statistically significant linear effect between the amount of noise and the annoyance. However, the objective results were inconclusive. This paper gives insight in the method to experience facade insulation interventions prior to construction.
- Department of Built Environment
About Maarten Hornikx
- My research field is acoustics of the built environment, with an emphasis on computational techniques. Please visit http://www.building-acoustics.net