Tim Lübeck

Tim Lübeck
Technische Hochschule Köln | FH Köln · Acoustic and Digital Audio Signal Processing Research Group

Master of Science

About

22
Publications
3,220
Reads
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92
Citations

Publications

Publications (22)
Article
Full-text available
Dynamic binaural synthesis requires binaural room impulse responses (BRIRs) for each head orientation of the listener. Such BRIRs can either be measured with a dummy head or calculated from the spherical microphone array (SMA) data. Because the dense dummy head measurements require enormous effort, alternatively sparse measurements can be performed...
Article
Full-text available
High-quality rendering of spatial sound fields in real-time is becoming increasingly important with the steadily growing interest in virtual and augmented reality technologies. Typically, a spherical microphone array (SMA) is used to capture a spatial sound field. The captured sound field can be reproduced over headphones in real-time using binaura...
Conference Paper
Full-text available
Open-source database download: https://doi.org/10.5281/zenodo.5031335
Conference Paper
Full-text available
The use of individual head-related transfer functions (HRTFs) can improve the quality of binaural reproduction in virtual acoustic environments. However, measuring individual HRTFs for a large number of directions is usually challenging in terms of time, effort, hardware, and setup requirements. This work presents an HRTF measurement system that ca...
Conference Paper
Full-text available
The Interactive Virtual Environment System (IVES) is a toolkit aiding the production of immersive audiovisual 3D virtual environments for screen-based or virtual reality (VR) applications with loudspeaker-or headphone-based spatial audio reproduction. It is developed within Cycling 74s Max programming environment and consists of a set of interface-...
Article
With the COVID-19 pandemic, the wearing of face masks covering mouth and nose has become ubiquitous all around the world. This study investigates the impact of typical face masks on voice radiation. To analyze the transmission loss caused by masks and the influence of masks on directivity, this study measured the full-spherical voice directivity of...
Data
Supplementary materials for "Impact of face masks on voice radiation" The Journal of the Acoustical Society of America, 148(6) pp. 3663-3670 (2020); https://doi.org/10.1121/10.0002853 . The dataset contains all measured directivities in SOFA format according to the SOFA convention "GeneralFIR". The directivities were measured on a 2702 sampling po...
Conference Paper
Full-text available
Employing a finite number of discrete microphones, instead of a continuous distribution according to theory, reduces the physical accuracy of sound field representations captured by a spherical microphone array. For a binaural reproduction of the sound field, a number of approaches have been proposed in the literature to mitigate the perceptual imp...
Conference Paper
Spatial upsampling of head-related transfer functions (HRTFs) measured on a sparse grid is an important issue, particularly relevant when capturing individual datasets. While early studies mostly used nearest-neighbor approaches, ongoing research focuses on interpolation in the spherical harmonics (SH) domain. The interpolation can either be perfor...
Conference Paper
Binaural auralization applying binaural room impulse responses (BRIRs) requires a high measurement effort and immense computing capacity when rendered with maximum spatial resolution. In this study, we conducted an adaptive ABX listening test to determine the minimum grid resolution (i.e., the spatial resolution) of BRIRs sufficient to achieve an a...
Article
Full-text available
Spherical microphone arrays (SMAs) are widely used to capture spatial sound fields that can then be rendered in various ways as a virtual acoustic environment (VAE) including head-phone-based binaural synthesis. Several practical limitations have a significant impact on the fidelity of the rendered VAE. The finite number of microphones of SMAs lead...
Conference Paper
Spatial composition represents a key aspect of contemporary acousmatic and computer music. The history of spatial composition practice has shown many different approaches of composition and performance tools, instruments and interfaces. Furthermore, current developments and the increasing availability of virtual/augmented reality systems (XR) exten...
Conference Paper
We developed an analog rigid sphere microphone array with 64 microphones arranged according to the Fliege sampling grid. The array is suited for spherical harmonics processing and allows resolving spatial resolutions up to an order of N = 7. Incorporating a rapid prototyping approach, most parts of the array are 3D printable and script-based modifi...
Conference Paper
Full-text available
We recently presented ReTiSAR, a framework for binaural rendering of spherical microphone array data in real-time. The array signals and the employed head-related transfer functions are processed in the spherical harmonics domain to compute the resulting ear signals and virtually place a listener into the captured sound field. In this contribution,...
Conference Paper
Full-text available
The progress of consumer-oriented multimedia towards virtual and augmented reality creates the demand for easy and user-friendly systems to obtain individual HRTF (head related transfer function) datasets. An adequate approach could be a self-driven measurement system, where a user, whose head-orientation is tracked, moves his head freely and trigg...
Conference Paper
Full-text available
The increased research in spatial audio processing and technical achie- vements in mixed reality systems created a demand for appropriate mi- crophone arrays to record and reproduce immersive spatial audio. Cur- rent findings in research show that high order spherical microphone ar- rays can be a good choice for an adequate reproduction, but unfort...
Conference Paper
Full-text available
Research on virtual acoustic environments (VAEs) has gained more and more interest in the last decades. In this context, VAEs have become an accepted research tool for performing psychoacoustic experiments. However, such experiments were often carried out under varying con- ditions. There were differences in the VAE systems, in the method of report...
Conference Paper
Reactive virtual acoustic environments (VAEs) that respond to any user-generated sound with an appropriate acoustic room response enable immersive audio applications with enhanced sonic interaction between the user and the VAE. This paper presents a reactive VAE that has two clear advantages in comparison to other systems introduced so far: it gene...
Poster
Full-text available
In the ongoing research project NarDasS, we developed a system for binaural reproduction of self-generated sound in virtual acoustic environments (VAEs). A 32-channel surrounding spherical microphone array captures the direction-dependent sound of an acting user. Based on these captured signals and specific BRIRs (BRIR - Binaural Room Impulse Respo...
Conference Paper
Full-text available
In the ongoing research project NarDasS, we developed a system for binaural reproduction of self-generated sound in virtual acoustic environments (VAEs). A 32-channel surrounding spherical microphone array captures the direction-dependent sound of an acting user. Based on these captured signals and specific BRIRs (BRIR - Binaural Room Impulse Respo...

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Project (1)
Project
It is a specific characteristic of the human voice that its directivity pattern shows time-dependent fluctuations while speaking or singing. It is the goal of the project to study human voice directivity. For this, the directivity is typically captured on a sparse grid, and methods for spatial upsampling need to be applied in order to obtain a high-resolution dataset on a dense sampling grid. Various aspects of human voice directivity are investigated, like phoneme-dependencies or interindividual differences. Furthermore, in this project, we plan to analyze the perceptual influence of these aspects as well.