3,981 research outputs found
Majdak, Piotr ; Noisternig, Markus: Implementation kopfpositionsbezogener Binauraltechnik
No full textGraz, Univ. für Musik und darstellende Kunst, Diplomarb., 200
FrAMBI: A Software Framework for Auditory Modeling Based on Bayesian Inference
No full textResearch in hearing science often relies on auditory models to describe listener's behaviour and its neural underpinning in acoustic environments. These models gather empirical evidence from behavioural data to address research questions on the neural mechanisms underlying sound perception. Despite seemingly similar statistical methods, auditory models are often implemented for each study separately, which hinders reproducibility and across-study comparisons, thus limiting the advancement at a field level. Here, we introduce a framework for studying neural mechanisms of sound perception by employing auditory modeling based on Bayesian inference (FrAMBI), a MATLAB/Octave toolbox. FrAMBI provides a standardized structure to implement an auditory model following the perception-action cycle and enables the automatic application of statistical analysis with behavioural data. We show FrAMBI's capabilities in several examples with increasing levels of complexity within the context of sound source localisation tasks: a basic implementation for a static scenario, iterating over the perception-action cycle with a moving sound source, the definition of multiple model variants testing different neural mechanisms, and the procedure for parameter estimation and model comparison. Being integrated into the widely used auditory modelling toolbox (AMT), FrAMBI is planned to be maintained in the long term and expanded accordingly, fostering reproducible research in the field of neuroscience
Majdak, Piotr: Lateralization of sounds based on interaural time differences in cochlear implant listeners
No full textGraz, Univ. für Musik und darstellende Kunst, Diss., 200
Majdak, Piotr: Head-related transfer functions and their role in the localization of sound sources in human listeners
No full textGraz, Univ. für Musik und darstellende Kunst, Habil.-schrift, 201
Sustainable tourism in valuable natural areas: theoretical contexts – strategies – applications
No full textPrezentowane w artykule rozważania skupiają się wokół problematyki rozwoju turystyki zrównoważonej na obszarach chronionych. Poruszane kwestie przybliżają zarówno teoretyczną, jak i praktyczną stronę zagadnienia rozwoju zrównoważonego. Analizom poddano rozmaite dokumenty, określające ramy funkcjonowania obszarów przyrodniczo cennych, jak i działania, które służą wdrażaniu przyjętych założeń. Zawarte w artykule analizy odnoszą się do dwóch krajów: Portugalii oraz Stanów Zjednoczonych Ameryki Północnej (USA). Wpływ na taki wybór miała różnorodność wynikająca z uwarunkowań przyrodniczych, geograficznych, przestrzennych oraz odmienność w sposobie zarządzania obszarami chronionymi wymienionych państw. Dzięki temu w proponowanym w artykule katalogu rozwiązań zaprezentowano szerokie spektrum działań, obejmujących zarówno inicjatywy wynikające z realizacji ogólnonarodowych projektów, jak i projekty realizowane na poziomie prywatnych firm czy lokalnych stowarzyszeń.The author focuses on the development of sustainable tourism in protected areas and the problems presented illustrate the theoretical as well as the practical side of such tourism. The analysis covers a range of documents which regulate the functioning of valuable natural areas, as well as defining the activities that serve to implement the assumptions that have been adopted. The analyses presented in the article concern two countries: Portugal and the United States of America. Their choice was determined by the differences between them resulting from their diverse natural, geographical, spatial conditions, as well as different methods of managing protected areas. The solutions proposed present a wide spectrum of activities including initiatives both originating from national projects and those run at the level of private firms or local associations.W artykule zostały zaprezentowane dane i informacje uzyskane na potrzeby projektu Innowacje w turystyce i rekreacyjnej aktywności fizycznej w paradygmacie zrównoważonego rozwoju: implementacja – percepcja – efekty, finansowanego w ramach działalności Społeczno-Humanistycznej Szkoły Badań Kultury Fizycznej Akademii Wychowania Fizycznego J. Piłsudskiego w Warszawie
Computational models for listener-specific predictions of spatial audio quality
Full text linkInternational audienceMillions of people use headphones every day for listening to music, watching movies, or communicating with others. Nevertheless, sounds presented via headphones are usually perceived inside the head instead of being localized at a naturally external position. Besides externalization and localization, spatial hearing also involves perceptual attributes like apparent source width, listener envelopment, and the ability to segregate sounds. The acoustic basis for spatial hearing is described by the listener-specific head-related transfer functions (HRTFs, Møller et al., 1995). Binaural virtual acoustics based on listener-specific HRTFs can create sounds presented via headphones being indistinguishable from natural sounds (Langendijk and Bronkhorst, 2000). In this talk, we will focus on the dimensions of sound localization that are particularly sensitive to listener-specific HRTFs, that is, along sagittal planes (i.e., vertical planes being orthogonal to the interaural axis) and near distances (sound externalization/internalization). We will discuss recent findings from binaural virtual acoustics and models aiming at predicting sound externalization (Hassager et al., 2016) and localization in sagittal planes (Baumgartner et al., 2014) considering the listener’s HRTFs. Sagittal-plane localization seems to be well understood and its model can already now reliably predict the localization performance in many listening situations (e.g., Marelli et al., 2015; Baumgartner and Majdak, 2015). In contrast, more investigation is required in order to better understand and create a valid model of sound externalization (Baumgartner et al., 2017). We aim to shed light onto the diversity of cues causing degraded sound externalization with spectral distortions by conducting a model-based meta-analysis of psychoacoustic studies. As potential cues we consider monaural and interaural spectral-shapes, spectral and temporal fluctuations of interaural level differences, interaural coherences, and broadband inconsistencies between interaural time and level differences in a highly comparable template-based modeling framework. Mere differences in sound pressure level between target and reference stimuli were used as a control cue. Our investigations revealed that the monaural spectral-shapes and the strengths of time-intensity trading are potent cues to explain previous results under anechoic conditions. However, future experiments will be required to unveil the actual essence of these cues.ReferencesBaumgartner, R., Majdak, P. (2015): Modeling Localization of Amplitude-Panned Virtual Sources in Sagittal Planes, in: Journal of Audio Engineering Society 63, 562-569.Baumgartner, R., Majdak, P., and Laback, B. (2014). “Modeling sound-source localization in sagittal planes for human listeners,” The Journal of the Acoustical Society of America 136, 791–802.Baumgartner, R., Reed, D. K., Tóth, B., Best, V., Majdak, P., Colburn, H. S., and Shinn-Cunningham, B. (2017). “Asymmetries in behavioral and neural responses to spectral cues demonstrate the generality of auditory looming bias,” Proceedings of the National Academy of Sciences 114, 9743–9748.Hassager, H. G., Gran, F., and Dau, T. (2016). “The role of spectral detail in the binaural transfer function on perceived externalization in a reverberant environment,” The Journal of the Acoustical Society of America 139, 2992–3000.Langendijk, E. H., and Bronkhorst, A. W. (2000). “Fidelity of three-dimensional-sound reproduction using a virtual auditory display,” J Acoust Soc Am 107, 528–37.Marelli, D., Baumgartner, R., and Majdak, P. (2015). “Efficient Approximation of Head-Related Transfer Functions in Subbands for Accurate Sound Localization,” IEEE Transactions on Audio, Speech, and Language Processing 23, 1130–1143.Møller, H., Sørensen, M. F., Hammershøi, D., and Jensen, C. B. (1995). “Head-related transfer functions of human subjects,” J Audio Eng Soc 43, 300–321
PHOnA: A Public Dataset of Measured Headphone Transfer Functions
No full textA dataset of measured headphone transfer functions (HpTFs), the Princeton Headphone Open Archive (PHOnA), is presented. Extensive studies of HpTFs have been conducted for the past twenty years, each requiring a separate set of measurements, but this data has not yet been publicly shared. PHOnA aggregates HpTFs from different laboratories, including measurements for multiple different headphones, subjects, and repositionings of headphones for each subject. The dataset uses the spatially..
Horizontal-plane HRTFs of KEMAR mannequin spatially interpolated with a resolution of 0.5°
No full text<p>HRTFs of the KEMAR manikin (Gardner and Martin, 1995):</p>
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<li>"hrtf_M_normal pinna.sofa": the original HRTF dataset from the KEMAR manikin at a lateral resolution of 5° stored as a SOFA file (Majdak et al., 2013)</li>
<li>"hrtf_M_normal pinna resolution 0.5 deg.sofa": A super-resolution HRTF set with a directional up-sampling of the original HRTF set to the lateral resolution of 0.5°. To this end, for each ear's HRTF set:
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<li>The broadband timing was removed by replacing the HRTF's phase spectrum by the minimum-phase spectrum (Oppenheim et al. 1999) corresponding to HRTF's amplitude spectrum.</li>
<li>For the interpolation of the amplitude spectra, the complex spectra of the minimum-phase HRTFs for two adjacent available directions were averaged according to a weighting that corresponded to the interpolated target direction. </li>
<li>For the interpolation of the timing, a continuous-direction model of the time-of-arrival (TOA) was applied (Ziegelwanger & Majdak, 2014). TOA is the broadband delay arising from the propagation paths from the sound source to the listener's ear. For a given direction of a sound, the interaural difference of TOAs corresponds to the ITD. The TOA model parameters describe listener's geometry (head and ears) and configure a continuous-direction function of broadband TOA. We used this function to calculate TOAs for directions in steps of 0.5°. To this end, for each ear, the model was fit to an HRTF set as described by Majdak & Ziegelwanger (2013) using the implementation from the Auditory Modeling Toolbox (Søndergaard & Majdak, 2013). Then, each minimum-phase HRTF was temporally up-sampled by a factor of 64, circularly shifted by the TOA obtained from the continuous-direction TOA model for the target direction, and then down-sampled to the sampling rate of 44.1 kHz. Note that the temporal oversampling was required to achieve an interaural resolution of 0.35 µs. </li>
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Predicting Directional Sound-Localization of Human Listeners in both Horizontal and Vertical Dimensions
No full textMeasuring and understanding spatial hearing is a fundamental step to create effective virtual auditory displays (VADs). The evaluation of such auralization systems often requires psychoacoustic experiments. This process can be time consuming and error prone, resulting in a bottleneck for the evaluation complexity. In this work we evaluated a probabilistic auditory model for sound localization intended as a tool to assess VAD's abilities to provide static sound-localization cues to listeners. The outcome of the model, compared with actual results of psychoacoustic experiments, shows the advantages and limitations of this systematic evaluation
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