Just noticeable reverberation difference at varying loudness levels. - In: AES Europe 2023, (2023), S. 361-368
In order to successfully fuse virtual sound sources with the real acoustic environment, the acoustic properties of the real environment must be estimated and utilized for the synthesis of virtual sound sources. Often, just noticeable differences (JNDs) of room acoustic parameters are utilized to predict a good match between virtual and real acoustics. However, several studies in this domain have shown that existing JND values of room acoustic parameters are often not able to predict the perception of the listeners. This can have various reasons: Differences in first reflection patterns are barely measurable with classical acoustic parameters; Even if acoustic differences are above the JND, a plausible reproduction might still be possible; JNDs depend on various factors (such as sound signal, etc.) and existing studies do not cover all of them. The last factor is addressed in this research paper. A three-alternative forced (3AFC) choice test was conducted at four different loudness levels (75 dB(A), 65 dB(A), 55 dB(A), and 45 dB(A)) in a reverberation time range from 0.5 s to 0.8 s. A dependency of the loudness on the detectability of reverberation differences was found for the randomly interleaved presentation of loudness levels but not for sequential presentation. Individual hearing thresholds as well as expertise level significantly influence the JND of reverberation time.
Robust reverberation time estimation for audio augmented reality applications. - In: AES Europe 2023, (2023), S. 47-55
The paper presents an alternative approach for estimating reverberation time from measurements in real rooms when the requirements of the standard DIN EN ISO 3382-1/2 for the characteristics of the sound source, receiver, and measurement positions cannot be met. The main goal is to minimize the variance of the calculated reverberation times when using a directional source and receiver, or source-receiver relative positions with very small distances. For this purpose, the energy decay curve for individual octave bands is sampled in time. The estimation starts 2 ms after the direct sound. This is followed by several estimates of the RT over a 20 dB drop, starting 1 dB later with each iteration. The best fit mean of these values gives the estimated reverberation time. A comparison with the standard reverberation time estimation shows a variance reduction of 10% to 30% for binaural room impulse responses (BRIRs). The proposed method finds its application in situations where measurements can only be made at a few positions in the room and/or only in a few areas of the room. Furthermore, the method should be better suitable for measurements with receivers located near or at the head of a person.
Discussion of acoustic and perceptual optimization methods for measuring spatial room impulse responses with a mobile robotic platform. - In: 2023 Immersive and 3D Audio: from Architecture to Automotive (I3DA), (2023), insges. 7 S.
In the field of Auditory Augmented Reality (AAR), one aim is to provide a listening experience that is as close as possible to a real scenario. Measured Spatial Room Impulse Responses (SRIRs) describe the acoustics of a room and can serve as a reference for acoustic simulations or parametrization of room acoustics. In previous works, a measurement system for SRIRs using a mobile robotic platform was introduced. The system consists of a commercially available self-driving platform on which a microphone array is mounted, while the sound sources are distributed at fixed positions in the room. The system is able to conduct high spatial resolution measurements of SRIRs in a uniform grid. In applications where time is limited and/or the area to discover is large, however, a high-resolution measurement is not always feasible.Therefore, the goal of this contribution is to compare different approaches for optimizing the measurement grid. One approach is to use mathematical optimization on acoustic parameters derived from a small set of initial measurements to determine new measurement positions in a iterative manner. Another approach is to optimize the measurement grid in respect to human auditory perception, incorporating e.g. just-noticeable differences of distance and localization perception.The results show that both approaches can achieve significant reductions in the number of measurements required for a adequate acoustic spatial reproduction, with different trade-offs depending on the application scenario and the available prior information.
https://doi.org/10.1109/I3DA57090.2023.10289338
The ability to memorize acoustic features in a discrimination task. - In: Journal of the Audio Engineering Society, ISSN 0004-7554, Bd. 71 (2023), 5, S. 254-266
How humans perceive, recognize, and remember room acoustics is of particular interest in the domain of spatial audio. For the creation of virtual or augmented acoustic environments, a room acoustic impression matches the expectations of certain room classes or a specific room. These expectations are based on the auditory memory of the acoustic room impression. In this paper, the authors present an exploratory study to evaluate the ability of listeners to recognize room acoustic features. The task of the listeners was to detect the reference room in a modified ABX double-blind stimulus test that featured a pre-defined playback order and a fixed time schedule. Furthermore, the authors explored distraction effects by employing additional nonacoustic interferences. The results show a significant decrease of the auditory memory capacity within 10 s, which is more pronounced when the listeners were distracted. However, the results suggest that auditory memory depends on what auditory cues are available.
https://doi.org/10.17743/jaes.2022.0073
The R3VIVAL dataset: repository of room responses and 360 videos of a variable acoustics lab. - In: IEEE ICASSP 2023 conference proceedings, (2023), insges. 5 S.
This paper presents a dataset of spatial room impulse responses (SRIRs) and 360˚ stereoscopic video captures of a variable acoustics laboratory. A total of 34 source positions are measured with 8 different acoustic panel configurations, resulting in a total of 272 SRIRs. The source positions are arranged in 30˚ increments at concentric circles of radius 1.5, 2, and 3 m measured with a directional studio monitor, as well as 4 extra positions at the room corners measured with an omnidirectional source. The receiver is a 7 channel open microphone array optimized for its use with the Spatial Decomposition Method (SDM). The 8 acoustic configurations are achieved by setting a subset of the panels to their absorptive configuration in 5 steps (0%, 25%, 50%, 75%, 100% of the panels), as well as 3 configurations in which entire walls are set to their absorptive configuration (right, right/back, right/back/left). Video captures of the laboratory and a second room are obtained using a 360˚ stereoscopic camera with a resolution of 4096 × 2160 pixels, covering the same source/receiver combinations. Furthermore, we present an acoustic analysis of both time-energy and spatio-temporal parameters showcasing the differences in the measured configurations. The dataset, together with spatial analysis and rendering scripts, is publicly released in a GitHub repository1.
https://doi.org/10.1109/ICASSP49357.2023.10097257
A dataset of measured spatial room impulse responses in different rooms including visualization. - In: AES Europe Spring 2022, (2022), S. 621-625
In this contribution, an open-source dataset of captured spatial room impulse responses (SRIRs) is presented. The data was collected in different enclosed spaces at the Technische Universität Ilmenau using an open self-build microphone array design following the spatial decomposition method (SDM) guidelines. The included rooms were selected based on their distinctive acoustical properties resulting from their general build and furnishing as required by their utility. Three different classes of spaces can be distinguished, including seminar rooms, offices, and classrooms. For each considered space different source-receiver positions were recorded, including 360? images for each condition. The dataset can be utilized for various augmented or virtual reality applications, using either a loudspeaker or headphone-based reproduction alongside the appropriate head-related transfer function sets. The complete database, including the measured impulse responses as well as the corresponding images, is publicly available.
Auditory room identification in a memory task. - In: AES International Conference on Audio for Virtual and Augmented Reality (AVAR 2022), (2022), S. 132-141
How we perceive and remember room acoustics is of particular interest in the domain of spatial audio. For the creation of virtual or augmented acoustic environments, a room acoustic impression needs to be created which matches the expectations of certain room classes or a specific room. These expectations are based on the auditory memory of the acoustic room impression. In this paper, we present an exploratory study to evaluate the ability of listeners to remember specific rooms. The task of the listeners was to detect the reference room in a modified ABX double-blind stimulus test which featured a pre-defined playback order and a fixed time schedule. Furthermore, we explored distraction effects by employing additional non-acoustic interferences. The results show a significant decrease of the auditory memory capacity within ten seconds, which is more pronounced when the listeners were distracted. However, the results suggest that auditory memory depends on what auditory cues are available.
Augmented/mixed reality audio for hearables: sensing, control, and rendering. - In: IEEE signal processing magazine, ISSN 1558-0792, Bd. 39 (2022), 3, S. 63-89
Augmented or mixed reality (AR/MR) is emerging as one of the key technologies in the future of computing. Audio cues are critical for maintaining a high degree of realism, social connection, and spatial awareness for various AR/MR applications, such as education and training, gaming, remote work, and virtual social gatherings to transport the user to an alternate world called the metaverse. Motivated by a wide variety of AR/MR listening experiences delivered over hearables, this article systematically reviews the integration of fundamental and advanced signal processing techniques for AR/MR audio to equip researchers and engineers in the signal processing community for the next wave of AR/MR.
https://doi.org/10.1109/MSP.2021.3110108
Perceptual matching of room acoustics for auditory augmented reality in small rooms - literature review and theoretical framework. - In: Trends in hearing, ISSN 2331-2165, Bd. 26 (2022), S. 1-22
For the realization of auditory augmented reality (AAR), it is important that the room acoustical properties of the virtual elements are perceived in agreement with the acoustics of the actual environment. This perceptual matching of room acoustics is the subject reviewed in this paper. Realizations of AAR that fulfill the listeners? expectations were achieved based on pre-characterization of the room acoustics, for example, by measuring acoustic impulse responses or creating detailed room models for acoustic simulations. For future applications, the goal is to realize an online adaptation in (close to) real-time. Perfect physical matching is hard to achieve with these practical constraints. For this reason, an understanding of the essential psychoacoustic cues is of interest and will help to explore options for simplifications. This paper reviews a broad selection of previous studies and derives a theoretical framework to examine possibilities for psychoacoustical optimization of room acoustical matching.
https://doi.org/10.1177/23312165221092919
Towards determining thresholds for room divergence: a pilot study on perceived externalization. - In: 2021 Immersive and 3D Audio: from Architecture to Automotive (I3DA), (2021), insges. 7 S.
https://doi.org/10.1109/I3DA48870.2021.9610835
Towards determining thresholds for room divergence: a pilot study on detection thresholds. - In: 2021 Immersive and 3D Audio: from Architecture to Automotive (I3DA), (2021), insges. 7 S.
In binaural rendering, the room divergence effect refers to the decrease in perceived externalization due to a mismatch between the room acoustics of the virtual sounds and those of the listening space. However, it is currently unknown which specific acoustic differences cause this effect. In this work, we present a pilot study to determine detection thresholds between sound sources recorded under different acoustic conditions in a variable acoustics room. These results are intended to predict situations where divergence effects can be expected. The participants had to perform a triangle test where they could listen to three sound sources placed at different positions in the room. The test design was motivated by the fact that sound sources are not placed at the same position in real acoustic scenes. One sound source was recorded under different acoustic conditions than the other two, and the task for the participant was to detect the differing source. The test was conducted in the measured room using 3 DoF binaural reproduction and using a virtual reality (VR) headset to display a visual 360 capture of the room enabling the subjects to see the positions of the sources in the room. Detection rates are signal-dependent and increase with differences in reverberation time (RT). For the most critical signal in the test (castanets), an RT difference of 8% was detectable, while the difference was 15% across all conditions. Furthermore, we discuss the influence of sound source distance and absorption configuration (symmetric or asymmetric) on detection thresholds.
https://doi.org/10.1109/I3DA48870.2021.9610876
Auditive Adaptationsprozesse im Kontext räumlicher Audiowiedergabesysteme. - Ilmenau : Universitätsbibliothek, 2021. - 1 Online-Ressource (ii, 145 Seiten)
Technische Universität Ilmenau, Dissertation 2021
Das Ziel technischer Weiterentwicklungen im Bereich der Unterhaltungselektronik ist die Optimierung der Benutzererfahrung durch die stetige Verbesserung der audiovisuellen Wiedergabe. Durch die Fortschritte im Bereich virtueller und augmentierter Realitäten wurde das Ziel einer realitätsnahen Wiedergabe immer greifbarer. Werden die Sinnesreize so perfekt imitiert, dass es dem Nutzer nicht mehr möglich ist künstlich erzeugte Schallquellen von Realen zu unterscheiden, ist die Rede von einer auditiven Illusion. In erster Linie sind die damit verbundenen Herausforderungen technischer Natur. Allerdings führt eine exakte Reproduktion der Ohrsignale nicht zwangsläufig zur gleichen Wahrnehmung wie in der entsprechenden realen Situation. Neben sinnesübergreifenden Wechselwirkungen, liegt dies daran, dass unsere Wahrnehmung stark von unseren Erwartungen und Erfahrungen abhängt. Diese Erwartungen können sich je nach vorheriger Schallexposition ändern. In Bezug auf das räumliche Hören bedeutet dies, dass Menschen wahrscheinlich lernen können wie räumliche Signale und ihre Merkmale zu interpretieren sind. Solche Mechanismen und ihre Auswirkungen auf die wahrgenommene Qualität von räumlichen Audiowiedergabesystemen ist der Gegenstand dieser Arbeit. In Wahrnehmungsstudien wurde das Erlernen von Lokalisationsmerkmalen untersucht sowie Adaptationsprozesse bei der raumakustischen Wahrnehmung näher beleuchtet. Es wird betrachtet mit welchen Qualitätsdefiziten zu rechnen ist, wenn die Ohrsignale nicht korrekt reproduziert werden und wie sich die Qualitätsbeurteilung abhängig vom Training ändert. Die Ergebnisse deuten darauf hin, dass Lern- und Adaptationsprozesse ein ausschlaggebender Faktor für das Zustandekommen einer auditiven Illusion ist. Die Arbeit diskutiert sowohl die praktische Relevanz dieser Effekte als auch die zugrundeliegenden Lern- und Adaptationsvorgänge.
https://doi.org/10.22032/dbt.50107
Six-degrees-of-freedom parametric spatial audio based on one monaural room impulse response. - In: Journal of the Audio Engineering Society, ISSN 0004-7554, Bd. 69 (2021), 7/8, S. 557-575
Parametric spatial audio rendering is a popular approach for low computing capacity applications, such as augmented reality systems. However most methods rely on spatial room impulse responses (SRIR) for sound field rendering with 3 degrees of freedom (DoF), i.e., for arbitrary head orientations of the listener, and often require multiple SRIRs for 6-DoF rendering, i.e., when additionally considering listener translations. This paper presents a method for parametric spatial audio rendering with 6 DoF based on one monaural room impulse response (RIR). The scalable and perceptually motivated encoding results in a parametric description of the spatial sound field for any listener's head orientation or position in space. These parameters form the basis for the binaural room impulse responses (BRIR) synthesis algorithm presented in this paper. The physical evaluation revealed good performance, with differences to reference measurements at most tested positions in a room below the just-noticeable differences of various acoustic parameters. The paper further describes the implementation of a 6-DoF realtime virtual acoustic environment (VAE) using the synthesized BRIRs. A pilot study assessing the plausibility of the 6-DoF VAE showed that the system can provide a plausible binaural reproduction, but it also revealed challenges of 6-DoF rendering requiring further research.
https://doi.org/10.17743/jaes.2021.0009
Creation of auditory augmented reality using a position-dynamic binaural synthesis system - technical components, psychoacoustic needs, and perceptual evaluation. - In: Applied Sciences, ISSN 2076-3417, Bd. 11 (2021), 3, 1150, S. 1-20
For a spatial audio reproduction in the context of augmented reality, a position-dynamic binaural synthesis system can be used to synthesize the ear signals for a moving listener. The goal is the fusion of the auditory perception of the virtual audio objects with the real listening environment. Such a system has several components, each of which help to enable a plausible auditory simulation. For each possible position of the listener in the room, a set of binaural room impulse responses (BRIRs) congruent with the expected auditory environment is required to avoid room divergence effects. Adequate and efficient approaches are methods to synthesize new BRIRs using very few measurements of the listening room. The required spatial resolution of the BRIR positions can be estimated by spatial auditory perception thresholds. Retrieving and processing the tracking data of the listener’s head-pose and position as well as convolving BRIRs with an audio signal needs to be done in real-time. This contribution presents work done by the authors including several technical components of such a system in detail. It shows how the single components are affected by psychoacoustics. Furthermore, the paper also discusses the perceptive effect by means of listening tests demonstrating the appropriateness of the approaches.
https://doi.org/10.3390/app11031150
Creating auditory illusions with binaural technology. - In: The technology of binaural understanding, (2020), S. 623-663
It is pointed out that beyond reproducing the physically correct sound pressure at the eardrums, more effects play a significant role in the quality of the auditory illusion. In some cases, these can dominate perception and even overcome physical deviations. Perceptual effects like the room-divergence effect, additional visual influences, personalization, pose and position tracking as well as adaptation processes are discussed. These effects are described individually, and the interconnections between them are highlighted. With the results from experiments performed by the authors, the perceptual effects can be quantified. Furthermore, concepts are proposed to optimize reproduction systems with regard to those effects. One example could be a system that adapts to varying listening situations as well as individual listening habits, experience and preference.
Evaluation of spatial audio quality of the synthesis of binaural room impulse responses for new object positions. - In: 147th Audio Engineering Society Convention 2019, (2020), S. 972-981
The aim of auditory augmented reality is to create an auditory illusion combining virtual audio objects and scenarios with the perceived real acoustic surrounding. A suitable system like position-dynamic binaural synthesis is needed to minimize perceptual conflicts with the perceived real world. The needed binaural room impulse responses (BRIRs) have to fit the acoustics of the listening room. One approach to minimize the large number of BRIRs for all source-receiver relations is the synthesis of BRIRs using only one measurement in the listening room. The focus of the paper is the evaluation of the spatial audio quality. In most conditions differences in direct-to-reverberant-energy ratio between a reference and the synthesis is below the just noticeable difference. Furthermore, small differences are found for perceived overall difference, distance, and direction perception. Perceived externalization is comparable to the usage of measured BRIRs. Challenges are detected to synthesize more further away sources from a source position that is more close to the listening positions.
Synthesis of binaural room impulse responses for different listening positions considering the source directivity. - In: 147th Audio Engineering Society Convention 2019, (2020), S. 377-385
Perceptual aspects in spatial audio processing. - In: Proceedings of the 23rd International Congress on Acoustics, (2019), S. 3354-3360
Spatial audio processing includes recording, modification and rendering of multichannel audio. In all these fields there is the choice of either a physical representation or of perceptual approaches trying to achieve a target perceived audio quality. Classical microphone techniques on one hand and wave field synthesis, higher order ambisonics or certain methods of binaural rendering for headphone reproduction on the other hand target a good physical representation of sound. As it is known today, especially in the case of sound reproduction a faithful physical recreation of the sound wave forms ("correct signal at the ear drums") is neither necessary nor does it allow a fully authentic or even plausible reproduction of sound. 20 years ago, MPEG-4 standardized different modes for perception based versus physics based reproduction (called "Perceptual approach to modify natural source" and "Acoustic properties for physical based audio rendering"). In spatial rendering today, more and more the perceptual approach is used in state of the art systems. We give some examples of such rendering. The same distinction of physics based versus psychoacoustics (including cognitive effects) based rendering is used today for room simulation or artificial reverb systems. Perceptual aspects are at the heart of audio signal processing today.
https://edocs.tib.eu/files/e01mr19/1677542403.pdf
Real-time estimation of reverberation time for selection of suitable binaural room impulse responses. - In: Audio for virtual, augmented and mixed realities, (2019), S. 145-150
The aim of auditory augmented reality is to create a highly immersive and plausible auditory illusion combining virtual audio objects and scenarios with the real acoustic surrounding. For this use case it is necessary to estimate the acoustics of the current room. A mismatch between real and simulated acoustics will easily be detected by the listener and will probably lead to In-head localization or an unrealistic acoustic envelopment of the virtual sound sources. This publication investigates State-of-the-Art algorithms for blind reverberation time estimation which are commonly used for speech enhancement algorithms or speech dereverberation and applies them to binaural ear signals. The outcome of these algorithms can be used to select the most appropriate room out of a room database for example. A room database could include pre-measured or simulated binaural room impulse responses which could directly be used to realize a binaural reproduction. First results show promising results combined with low computational effort. Further strategies for enhancing the used method are proposed in order to create a more precise reverberation time estimation.
https://doi.org/10.22032/dbt.39968
Investigation on spatial auditory perception using non-uniform spatial distribution of binaural room impulse responses. - In: Audio for virtual, augmented and mixed realities, (2019), S. 137-144
For spatial audio reproduction in the context of virtual and augmented reality, a position-dynamic binaural synthesis can be used to reproduce the ear signals for a moving listener. A set of binaural room impulse responses (BRIRs) is required for each possible position of the listener in the room. The required spatial resolution of the BRIR positions can be estimated by spatial auditory perception thresholds. If the resolution is too low, jumps in perception of direction and distance and coloration effects occur. This contribution presents an evaluation of spatial audio quality using different spatial resolutions of the position of the used BRIRs. The evaluation is performed with a moving listener. The test persons evaluate any abnormalities in the spatial audio quality. The result is a comparison of the quality and the spatial resolution of the various conditions used.
https://doi.org/10.22032/dbt.39967
Innovative methods and technologies for spatial listening and speech intelligibility using hearing implants. - In: Adaptive processes in hearing, (2018), S. 343-350
Training on the acoustical identification of the listening position in a virtual environment. - In: 143rd Audio Engineering Society International Convention 2017, (2018), S. 205-212
Plausible augmentation of auditory scenes using dynamic binaural synthesis for personalized auditory realities. - In: Science, technology, design, and implementation, (2018), S. 258-267
The relevance of auditory adaptation effects for the listening experience in virtual acoustic environments. - In: 144th Audio Engineering Society International Convention 2018, (2018), S. 575-582
Adjustment of the Direct-to-Reverberant-Energy-Ratio to reach externalization within a binaural synthesis system. - In: Audio for virtual and augmented reality, ISBN 978-1-5108-4346-2, (2017), S. 120-126
Auditory illusion over headphones revisited. - In: The journal of the Acoustical Society of America, ISSN 1520-8524, Bd. 141 (2017), 5, S. 3997
https://doi.org/10.1121/1.4989160
Influence of head tracking on the externalization of auditory events at divergence between synthesized and listening room using a binaural headphone system. - In: 142nd Audio Engineering Society International Convention 2017, (2017), S. 17-24
GO-LEM - Charakterisierung der auditorischen und auditorisch-visuellen Wahrnehmung des Menschen in Alltagsszenen. - In: Prävention von arbeitsbedingten Gesundheitsgefahren und Erkrankungen, (2017), S. 349-356
Influences of training on externalization of binaural synthesis in situations of room divergence. - In: Journal of the Audio Engineering Society, ISSN 0004-7554, Bd. 65 (2017), 3, S. 178-187
https://doi.org/10.17743/jaes.2016.0072
Auditory illusion through headphones: history, challenges and new solutions. - In: 22nd International Congress on Acoustics (ICA 2016), (2016), S. 3063-3072
A summary on acoustic room divergence and its effect on externalization of auditory events. - In: QoMEX 2016, ISBN 978-1-5090-0354-9, (2016), insges. 6 S.
This contribution presents a summary of results from perceptual auditory experiments on context dependent quality parameters for virtual acoustic environments. The investigated quality features are influenced by divergence between synthesized scene and listening room and adaptation on congruence or divergence between the rooms. Two experiments are presented. The results from the first experiment show the room divergence effect on spatial auditory perception. A divergence between the listening room and binaurally synthesized room leads to a decrease of perceived externalization while congruence yields an increase. A more comprehensive statistical analysis regarding significance, effect size and visual influences is added to complement the original publication of this data. The second experiment shows this effect as the result of expectations of the listeners and can be shifted by adaptation and training. In the experiments we show, that training to congruent or divergent room combinations can increase or decrease the room divergence effect.
http://dx.doi.org/10.1109/QoMEX.2016.7498973
Variance in measured binaural room transfer functions of individuals. - In: Fortschritte der Akustik, ISBN 978-3-939296-10-2, (2016), S. 83-85
Auditory adaptation to non-individual HRTF cues in binaural audio reproduction. - In: Journal of the Audio Engineering Society, ISSN 0004-7554, Bd. 64 (2016), 1/2, S. 45-54
http://dx.doi.org/10.17743/jaes.2015.0092
Auditory adaptation in spatial listening tasks. - In: 138th Audio Engineering Society convention 2015, (2015), S. 521-530
Influence of spatial complexity and room acoustic disparity on perception of quality features using a binaural synthesis system. - In: 2015 Seventh International Workshop on Quality of Multimedia Experience (QoMEX), ISBN 978-1-4799-8959-1, (2014), insges. 6 S.
This contribution presents investigations on the influence of scene complexity and room acoustic disparity on the perception of different quality features using a binaural headphone system. The quality features "spatial presence" and "listener envelopment" are investigated next to "perceived externalization" and "localization" of an auditory event. The test uses three different rooms with distinct room acoustic characteristics and several scenes with different spatial complexity. The work addresses the question if the quality features can profit by the different audio scenes or not. The results show that spatial presence is influenced by spatial complexity while room acoustic disparity influences listener envelopment. Furthermore, externalization and localization are not affected by spatial complexity regardless of the personalization method used for binaural synthesis.
http://dx.doi.org/10.1109/QoMEX.2015.7148131
Kontextabhängige Parameter bei der Qualitätsbeurteilung binauraler Kopfhörersysteme. - In: Fortschritte der Akustik, (2015), S. 1599-1601
Distribution of quadrant errors in auditory localization using a binaural headphone system. - In: Fortschritte der Akustik, (2015), S. 1094-1096
The auditory system of humans enables the perception of spatial audio in real and virtual acoustics using monaural and binaural cues. The perception of direction and distance are two prominent quality features to evaluate the quality of experience of spatial audio systems. Inaccuracies in perception can occur if physical quality elements of the synthesis system are not adequate. In this study a binaural synthesis via headphones is used to re-synthesize single sound sources on several discrete positions on a full circle around the listener. An artificial head (KEMAR) and a two channel spherical microphone setup are used to measure binaural room impulse responses in a real environment. A listening test is performed to measure the number of quadrant errors and perceived externalization of the auditory events in a localization task. The distributions of its frequencies depending on the direction of the re-synthesized sound source are investigated. The results show a continuous relationship between the investigated quality features and the direction of the sound source. Furthermore, an analysis of the relationship between quadrant errors and externalization depending on direction and used binaural room impulse responses are presented.
Influence of context dependent quality parameters on the perception of externalization and direction of an auditory event. - In: Spatial audio, ISBN 978-1-63439-759-9, (2015), S. 305-312
Next to an adequate technical realization of an audio reproduction system, the context of usage plays a major role if a perfect auditory illusion with immersion and plausibility is aspired. This contribution presents results from perceptual experiments on context dependent quality parameters. A binaural synthesis of an acoustic scene via a personalized headphone system is used. The investigated quality parameters are influenced by divergence between synthesized scene and listening room, visibility of the scene, and personalization of the system. The plausibility of the perceived auditory scene is described by the test persons with the help of the quality features perceived externalization and direction of the auditory event. The analysis shows that there are significant differences in perceived externalization depending on the occurrence of localization errors but also on divergence or congruence between the listening and synthesized room.
Context and plausibility in binaural synthesis. - In: Proceedings of the International Conference on Spatial Audio, ICSA 2014 in Erlangen, Germany, ISBN 978-3-9812830-4-4, (2014), S. 189-192
The development of recording and playback systems is motivated by the goal to create a perfect auditory illusion. In the last decades audio systems like ambisonics, wave field synthesis and binaural headphone reproduction gained in importance. Efforts are made to increase the quality of such systems. Despite the years of research and development, there are still many perceptual effects and psychoacoustical factors which are still unknown or not fully understood. This contribution presents a research project which deals with the systematically analysis of perceptual effects regarding to binaural playback. Based on the results of listening tests a measurement model on the perception of binaural synthesized scenes is developed. For this, a set of quality features needs to be determined and evaluated. These quality features and their weightings can be summarized as plausibility of perception. The plausibility of a binaural auralization does not only depend on physical quality elements of the synthesis system, but also depends significantly on contextual factors. During the project several different auditive scenes are created for evaluation. The contextual factors which influence the quality features are varied. Different rooms for playback and recording are considered as well as variations of the complexity of the acoustical scene, the degree of personalization and the type of visual presentation. Dependencies between these factors are expected and are going to be evaluated. This contribution presents first results of contextual factors influencing quality features.
Perspektiven zur Anwendung der Binauralsynthese in der Medienproduktion. - In: Medienproduktion, ISSN 2193-7699, No. V (2014), Seite 12-14
http://zs.thulb.uni-jena.de/receive/jportal_jpvolume_00202970
HRTF adaption under decreased immersive conditions. - In: AIA-DAGA 2013, ISBN 978-3-939296-05-8, (2013), S. 580-582
Influence of base width of a two channel crosstalk canceller on the localization of simulated sound sources. - In: Expertise in audio media, ISBN 978-3-9812830-3-7, (2013), S. 607-613
On the influence of visual feedback on vertical sound source localization. - In: Proceedings of ICSA 2011, ISBN 978-3-9812830-2-0, (2011), S. 523-526
Individualization of head-related transfer functions. - In: Fortschritte der Akustik, (2011), S. 375-376
(Abhängigkeit der binauraler Auralisation über Kopfhörer von den Abhörbedingungen) :
Dependencies of binaural auralization via headphones on listening conditions. - In: Fortschritte der Akustik, (2011), S. 665-666
Individualisierte Entzerrung von Außenohrübertragungsfunktionen. - 90 S. Ilmenau : Techn. Univ., Diplomarbeit, 2011
Im Rahmen der Binauraltechnik muss den Außenohrübertragungsfunktionen (Head-Related Transfer Functions - HRTFs) besondere Aufmerksamkeit gewidmet werden. Die Verwendung nicht-individualisierter HRTFs, wie sie beispielsweise durch Messungen mit einem Kunstkopf entstehen, führt zu Fehlern bei der auditiven Wahrnehmung. Die Folgen sind erhöhte Lokalisationsunschärfen sowie fehlende Externalisierung von Hörereignissen. Es wird ein Algorithmus zur Bestimmung individualisierter HRTFs auf Basis von anthropometrischen Daten vorgestellt. Die CIPIC HRTF-Datenbank, welche zusätzlich anthropometrische Daten von 45 Probanden enthält, dient als Grundlage für den Algorithmus. Zur Reduktion der Komplexität der HRTF-Daten wird eine Hauptkomponentenanalyse durchgeführt. Mit Hilfe einer Regressionsanalyse werden Zusammenhänge zwischen den anthropometrischen Daten und dem Verlauf des HRTF-Amplitudenspektrums aus einer bestimmten Richtung bestimmt. Für die anthropometrischen Daten neuer Probanden lässt sich somit eine HRTF-Prädiktion durchführen. Anhand sechs neu vermessener Probanden wurde das Verfahren getestet. Die Ergebnisse zeigen starke Unterschiede in der Prädiktionsleistung zwischen den HRTFs verschiedener Ohren. Dies ist auf niedrige Korrelationskoeffizienten zwischen anthropometrischen Daten und den HRTF-Amplitudenspektren zurückzuführen. Als ein erschwerender Faktor stellte sich die mangelhafte Reproduzierbarkeit von akustischen und anthropometrischen Messungen heraus. In einem MUSHRA-Hörtest mit den vermessenen Probanden konnten in Hinsicht auf Externalität, Lokalisationsunschärfe und Klangfarbenveränderungen keine wesentlichen Verbesserungen gegenüber Kunstkopfaufnahmen für die meisten Probanden festgestellt werden. Die erwarteten Verbesserungen bezüglich der Prädiktionsergebnisse spiegeln sich nur unzureichend in dem durchgeführten Hörtest wieder. Bei der Verwendung eines ABX-Hörtests mit einer größeren Anzahl von Probanden wird ein aussagekräftigeres Ergebnis erwartet.
Interaktiver audiovisueller Demonstrator psychoakustischer Phänomene. - In: Fortschritte der Akustik, (2010), S. 183-184