| 1. |
- Ahrens, Jens, 1978, et al.
(author)
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Perceptual evaluation of headphone auralization of rooms captured with spherical microphone arrays with respect to spaciousness and timbre
- 2019
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In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 1520-8524 .- 0001-4966. ; 145:4, s. 2783-2794
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Journal article (peer-reviewed)abstract
- A listening experiment is presented in which subjects rated the perceived differences in terms of spaciousness and timbre between a headphone-based headtracked dummy head auralization of a sound source in different rooms and a headphone-based headtracked auralization of a spherical microphone array recording of the same scenario. The underlying auralizations were based on mea- sured impulse responses to assure equal conditions. Rigid-sphere arrays with different amounts of microphones ranging from 50 to up to 1202 were emulated through sequential measurements, and spherical harmonics orders of up to 12 were tested. The results show that the array auralizations are partially indistinguishable from the direct dummy head auralization at a spherical harmonics order of 8 or higher if the virtual sound source is located at a lateral position. No significant reduction of the perceived differences with increasing order is observed for frontal virtual sound sources. In this case, small differences with respect to both spaciousness and timbre persist. The evaluation of lowpass-filtered stimuli shows that the perceived differences occur exclusively at higher frequen- cies and can therefore be attributed to spatial aliasing. The room had only a minor effect on the results.
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| 2. |
- Alvarsson, Jesper J., et al.
(author)
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Aircraft noise and speech intelligibility in an outdoor living space
- 2014
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In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 135:6, s. 3455-3462
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Journal article (peer-reviewed)abstract
- Studies of effects on speech intelligibility from aircraft noise in outdoor places are currently lacking. To explore these effects, first-order ambisonic recordings of aircraft noise were reproduced outdoors in a pergola. The average background level was 47 dB L-Aeq. Lists of phonetically balanced words (L-ASmax,L- word = 54 dB) were reproduced simultaneously with aircraft passage noise (L-ASmax,L- noise = 72-84 dB). Twenty individually tested listeners wrote down each presented word while seated in the pergola. The main results were (i) aircraft noise negatively affects speech intelligibility at sound pressure levels that exceed those of the speech sound (signal-to-noise ratio, S/N < 0), and (ii) the simple A-weighted S/N ratio was nearly as good an indicator of speech intelligibility as were two more advanced models, the Speech Intelligibility Index and Glasberg and Moore's [J. Audio Eng. Soc. 53, 906-918 (2005)] partial loudness model. This suggests that any of these indicators is applicable for predicting effects of aircraft noise on speech intelligibility outdoors.
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| 3. |
- Arehart, Kathryn, et al.
(author)
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Relationship between distortion and working memory for digital noise-reduction processing in hearing aids
- 2014
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In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 133:5
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Journal article (peer-reviewed)abstract
- Several recent studies have shown a relationship between working memory and the ability of older adults to benefit from specific advanced signal processing algorithms in hearing aids. In this study, we quantify tradeoffs between benefit due to noise reduction and the perceptual costs associated with distortion caused by the noise reduction algorithm. We also investigate the relationship between these tradeoffs and working memory abilities. Speech intelligibility, speech quality, and perceived listening effort were measured in a cohort of elderly adults with hearing loss. Test materials were low-context sentences presented in fluctuating noise conditions at several signal-to-noise ratios. Speech stimuli were processed with a binary mask noise-reduction strategy. The amount of distortion produced by the noise reduction algorithm was parametrically varied by manipulating two binary mask parameters, error rate, and attenuation rate. Working memory was assessed with a reading span test. Results will be discussed in terms of the extent to which intelligibility, quality, and effort ratings are explained by the amount of distortion and/or noise and by working memory ability. [Funded by NIH, Oticon, and GN ReSound.].
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| 4. |
- Arnela, Marc, et al.
(author)
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Influence of lips on the production of vowels based on finite element simulations and experiments
- 2016
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In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 139:5, s. 2852-2859
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Journal article (peer-reviewed)abstract
- Three-dimensional (3-D) numerical approaches for voice production are currently being investigated and developed. Radiation losses produced when sound waves emanate from the mouth aperture are one of the key aspects to be modeled. When doing so, the lips are usually removed from the vocal tract geometry in order to impose a radiation impedance on a closed cross-section, which speeds up the numerical simulations compared to free-field radiation solutions. However, lips may play a significant role. In this work, the lips' effects on vowel sounds are investigated by using 3-D vocal tract geometries generated from magnetic resonance imaging. To this aim, two configurations for the vocal tract exit are considered: with lips and without lips. The acoustic behavior of each is analyzed and compared by means of time-domain finite element simulations that allow free-field wave propagation and experiments performed using 3-D-printed mechanical replicas. The results show that the lips should be included in order to correctly model vocal tract acoustics not only at high frequencies, as commonly accepted, but also in the low frequency range below 4 kHz, where plane wave propagation occurs.
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| 5. |
- Arnela, Marc, et al.
(author)
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Influence of vocal tract geometry simplifications on the numerical simulation of vowel sounds
- 2016
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In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 140:3, s. 1707-1718
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Journal article (peer-reviewed)abstract
- For many years, the vocal tract shape has been approximated by one-dimensional (1D) area functions to study the production of voice. More recently, 3D approaches allow one to deal with the complex 3D vocal tract, although area-based 3D geometries of circular cross-section are still in use. However, little is known about the influence of performing such a simplification, and some alternatives may exist between these two extreme options. To this aim, several vocal tract geometry simplifications for vowels [ɑ], [i], and [u] are investigated in this work. Six cases are considered, consisting of realistic, elliptical, and circular cross-sections interpolated through a bent or straight midline. For frequencies below 4–5 kHz, the influence of bending and cross-sectional shape has been found weak, while above these values simplified bent vocal tracts with realistic cross-sections are necessary to correctly emulate higher-order mode propagation. To perform this study, the finite element method (FEM) has been used. FEM results have also been compared to a 3D multimodal method and to a classical 1D frequency domain model.
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| 6. |
- Auregan, Yves, et al.
(author)
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Low frequency sound attenuation in a flow duct using a thin slow sound material
- 2016
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In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 139:5, s. EL149-EL153
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Journal article (peer-reviewed)abstract
- A thin subwavelength material that can be flush mounted in a duct and that gives an attenuation band at low frequencies in air flow channels is presented. To decrease the material thickness, the sound is slowed in the material using folded side branch tubes. The impedance of the material is compared to the optimal value given by the Cremer condition, which can differ greatly from the air characteristic impedance. Grazing flow on this material increases the losses at the interface between the flow and the material.
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| 7. |
- Axelsson, Östen, et al.
(author)
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A principal components model of soundscape perception
- 2010
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In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 128:5, s. 2836-2846
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Journal article (peer-reviewed)abstract
- There is a need for a model that identifies underlying dimensions of soundscape perception, and which may guide measurement and improvement of soundscape quality. With the purpose to develop such a model, a listening experiment was conducted. One hundred listeners measured 50 excerpts of binaural recordings of urban outdoor soundscapes on 116 attribute scales. The average attribute scale values were subjected to principal components analysis, resulting in three components: Pleasantness, eventfulness, and familiarity, explaining 50, 18 and 6% of the total variance, respectively. The principal-component scores were correlated with physical soundscape properties, including categories of dominant sounds and acoustic variables. Soundscape excerpts dominated by technological sounds were found to be unpleasant, whereas soundscape excerpts dominated by natural sounds were pleasant, and soundscape excerpts dominated by human sounds were eventful. These relationships remained after controlling for the overall soundscape loudness (Zwicker’s N10), which shows that ‘informational’ properties are substantial contributors to the perception of soundscape. The proposed principal components model provides a framework for future soundscape research and practice. In particular, it suggests which basic dimensions are necessary to measure, how to measure them by a defined set of attribute scales, and how to promote high-quality soundscapes.
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| 8. |
- Axelsson, Östen
(author)
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Progress in soundscape research requires a common agenda
- 2011
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In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 130:4, s. 2495-2495
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Journal article (other academic/artistic)abstract
- It is commonly believed that progress and success in any field requires competition. This is probably true, but this belief implies that all competitors have a common view on the objectives. There would not be much competition if all parties ran off in opposite directions, striving to achieve different goals. Nor would it lead to much progress. The present session calls for networking and international collaboration in soundscape research. For such collaboration to be successful, it is critical to agree on a common agenda; a mission; an objective. Recent development in soundscape research makes evident that the objective must be practical and applicable. Our minds must be set to implementing soundscape research in practice to avoid exhausting academic debates, which tend to be ends in themselves and do not contribute to progress. Two excellent, recent examples of international collaboration in soundscape research, contributing to progress, are ISO/TC 43/SC 1/WG 54 and the European COST Action TD0804 “Soundscape of European Cities and Landscapes.” Both illustrate the need for international and interdisciplinary collaboration among acousticians, architects, and urban planners to accelerate progress in soundscape research. The present paper presents possible topics for a common agenda in soundscape research.
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| 9. |
- Axelsson, Östen
(author)
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The ISO 12913 series on soundscape : An update, May 2012
- 2012
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In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 131:4
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Journal article (peer-reviewed)abstract
- In February 2009 the working group ISO/TC 43/SC 1/WG 54 “Perceptual assessment of soundscape quality”, of the International Organization for Standardization (ISO), begun preparing the first International Standard on soundscape “ISO 12913-1 Acoustics — Soundscape — Part 1: Definition and conceptual framework”. This paper presents the latest version of the definition of “soundscape” and its conceptual framework. At its current state of development the framework highlights seven general concepts and their relationships: (1) sound sources, (2) acoustic environment, (3) auditory sensations, (4) interpretation of auditory sensations, (5) responses, (6) context, and (7) outcomes. By providing a standard reference, the working group aims at international consensus in order to avoid ambiguity, and to enable conceptual progress in soundscape research. ISO 12913-1 is expected to be published as an International Standard in 2015. Subsequent parts of the ISO 12913 series will deal with minimum reporting requirements in soundscape research, and methods for measuring soundscape quality.
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| 10. |
- Axelsson, Östen
(author)
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Tower of Babel, or why bother about international standards?
- 2011
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In: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 130:4, s. 2467-2467
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Journal article (other academic/artistic)abstract
- While a vast nation like the USA has the capacity to be self-sufficient, many countries lack this privilege. Take Sweden as an example, a small country in northern Europe with a population of 9 million. Swedes are proud to be international. And they should, because how could a nation, which since the days of the Vikings has depended on international trade, sustain itself without a global economy. International standards support the development within this global economy, just like English as business language facilitates global collaboration. Imagine humanity without these common frames of reference.
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