According to ISO 345, the random-incidence sound absorption coefficient is measured in a reverberation room by determining the different reverberation times with and without the absorber inserted. The sound field in the room is assumed to be diffuse. Thus, the corresponding energy decay curves would be strictly exponential, but turn out to represent multiple decay […]

Poor acoustic conditions in educational institutions affect children. A noisy environment puts children under constant stress and impairs their performance. Most of the present research and standards concerning classroom acoustics focus on reverberation time and background noise level, although it is agreed upon that these measures do not provide comprehensive information on the noise perception […]

The goal of this thesis is building an extension that can reduce the interference of the noise in some precision measurement experiments, which means increasing the directivity of the microphone. To reach this goal, this thesis starts from the theory to the simulation, then build the prototypes and tested them in the experiments. Waveguide and […]

Binaural hearing is a complex process that is significantly influenced by physical attributes of the listener. These dependencies on the shape of the torso, head, but also the resonance properties of the pinna can be summarized in a digital filter, the so-called head-related transfer function (HRTF). Such HRTFs are not only widely used in the […]

In order to provide a diagnosis about the urban sound environment, especially for traffic, sound classification using deep learning with convolutional neural networks has received increasing attention. There are already some attempts of deep convolutional neural networks (CNN) for environmental sound classification and data augmentation. These CNNs are using spectro-temporal patterns as its input to […]

The impulse response of a room describes the acoustic transmission path between a given source and receiver. One way to acquired an impulse response is by using simulations of a virtual environment. With auralization techniques, such an impulse response can be employed to listen to the virtual room. In a following step, these simulations can […]

Lärm ist heutzutage ein großer Faktor, der die Gesundheit vieler Menschen beeinträchtigt. Dabei entstehen neben den direkten Schäden am Gehör, den auralen Lärmeffekten, auch weitere, nicht direkt gehörbezogene gesundheitliche Schäden z.B. durch psychischen Stress. Diese werden als extra-aurale Lärmeffekte beschrieben, mit denen auch eine mögliche schlechtere kognitive Leistung einhergeht. Um diese extra-auralen Effekte von Geräuschen […]

When assessing how aircraft noise is perceived by residents of nearby urban environments, auralization can be an effective tool. For this purpose, it is necessary to consider how propagation paths are impacted by both, the atmosphere and the urban environment. In the atmosphere, the inhomogeneity of the medium plays an important role on sound propagation, […]

In the context of the auralization of acoustic scenes in outdoor scenarios, the effects of the atmosphere on sound propagation are of crucial importance. Ray tracing is a common method for tracking paths between sources and receivers and can be used to compute atmospheric transfer functions when the height-dependent physical properties of the atmosphere are […]

Theoretischen Modellen für das Schallfeld über porösen Absorbern liegt in der Regel die Annahme einer mindestens in einer Dimension unendlich ausgedehnten Materialschicht zugrunde. In der praktischen Anwendung, zum Beispiel bei der inversen Bestimmung von Material- oder Oberflächeneigenschaften aus Schalldruckmessungen über allseitig finiten Proben, haben derartige analytische Ansätze entsprechend Grenzen, sodass zusätzliche Beugungsfelder an den Kanten […]

Noise can cause stress, which leads to measurable physical reactions as well as it can impair intentional switching of auditory selective attention (ASA). In children, this can reduce the learning progress and thus disturb their development. The relation of measurable physical stress reactions and intentional switching of ASA is investigated in current research with the […]

Ultrasonic Metal Welding (USMW) is solid-state bonding process where two metal pieces are joined by the application of ultrasonic vibrations. This thesis focuses on the study of the sonotrode during a free run to understand the airborne sound field generated during the welding process. Simulation data are generated using COMSOL Multiphysics to model the physics […]

In virtual audio, sound sources need to be modeled as realistically as possible to achieve a sense of immersion in the scene. The human auditory system performs an analysis of sound, which enables the extraction of different information to recognize and localize sound sources. There are various aspects known to result in the differences of […]

In this thesis, the mutual information and interaction between different objective distance metrics for HRTF comparison were analyzed and evaluated. For this purpose, tools such as correlation analysis, principal component analysis and factor analysis were used. The metrics were reduced to a smaller set of measures suitable for a listening experiment, covering both spatial and […]

Ultrasonic metal welding (USMW) is a kind of solid-state bonding technique for connecting similar or dissimilar metals using extremely fast frequency oscillations (ultrasonic frequencies). However, some details of vibration during the USMW are still unclear in this study field. In this work, 27 groups of measurements on the oscillation of the sonotrode and anvil vibrations […]

The acoustic scattering of surface is very important in all aspects of room acoustics like in concert halls and reverberation rooms. The acoustic propagation of sound can be calculated effectively and in high quality by geometrical simulation methods. Nevertheless, reliable scattering coefficients are needed. In this master’s thesis, the uncertainty of standardized measurement methods will […]

Open-plan offices have been popular for their significant advantages such as economical savings and flexible layout design. However, according to several questionnaire studies, noise, and in particular, irrelevant speech has been rated as the major source of annoyance in open-plan offices, which impairs concentration severely and causes productivity decline. As the Irrelevant Sound Effect (ISE) […]

Dieser Vortrag beschäftigt sich mit der Ersatzschaltbildmodellierung des Knochenschalls. Die Knochenleitung beschreibt die Übertragung von Schall als Schwingungen im Schädel Knochen und dem umgebenden Weichteilgewebe zum Innenohr. Es gibt fünf verschiedene Wege, die oft als wichtig für den Knochenleitung Schall angesehen werden: Schalldruck im Gehörgang, Trägheit des Mittelohrs, Trägheit der Innen Innenohrflüssigkeit, Kompression des Innenohrraums […]

People perceive most events with several senses at the same time. In everyday life, these different sensations coincide in time and space to form one coherent percept. However, in online conferencing, which has become an increasingly popular mean of communication, there may be a temporal and/or spatial mismatch between visual and auditory input, e.g., due […]