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  • 101. Ling, Jun
    et al.
    Li, Jian
    Stoica, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Automatic control.
    Datum, Michael
    Probing waveforms and adaptive receivers for active sonar2011In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 129, no 6, p. 3640-3651Article in journal (Refereed)
  • 102.
    Ling, Jun
    et al.
    Department of Electrical and Computer Engineering, University of Florida.
    Zhao, Kexin
    Department of Electrical and Computer Engineering, University of Florida.
    Li, Jian
    Department of Electrical and Computer Engineering, University of Florida.
    Nordenvaad, Magnus Lundberg
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Signals and Systems.
    Multi-input multi-output underwater communications over sparse and frequency modulated acoustic channels2011In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 130, no 1, p. 249-262Article in journal (Refereed)
    Abstract [en]

    This paper addresses multi-input multi-output (MIMO) communications over sparse acoustic channels suffering from frequency modulations. An extension of the recently introduced SLIM algorithm, which stands for sparse learning via iterative minimization, is presented to estimate the sparse and frequency modulated acoustic channels. The extended algorithm is referred to as generalization of SLIM (GoSLIM). The sparseness is exploited through a hierarchical Bayesian model, and because GoSLIM is user parameter free, it is easy to use in practical applications. Moreover this paper considers channel equalization and symbol detection for various MIMO transmission schemes, including both space-time block coding and spatial multiplexing, under the challenging channel conditions. The effectiveness of the proposed approaches is demonstrated using in-water experimental measurements recently acquired during WHOI09 and ACOMM10 experiments.

  • 103.
    Lingvall, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Brännmark, Lars-Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Multiple-point statistical room correction for audio reproduction: Minimum mean square error correction filtering2009In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 125, no 4, p. 2121-2128Article in journal (Refereed)
    Abstract [en]

    This paper treats the problem of correction of loudspeaker and room responses using a single source. The objective is to obtain a linear correction filter, which is robust with respect to listener movement within a predefined region-of-interest. The correction filter is based   on estimated impulse responses, obtained at several positions, and a linear minimum mean squared error criteria. The impulse responses are estimated using a Bayesian approach that takes both model errors and measurement noise into account, which results in reliable impulse response estimates and a measure of the estimation errors. The correction filter is then constructed by using information from both the estimated impulse response coefficients and their associated estimation errors. Furthermore, in the optimization criteria a time-dependent reflection filter is introduced, which attenuates the high frequency parts of the reflected responses, that is, the parts of the responses that cannot be compensated with a single source system. The resulting correction filter is shown to significantly improve both   the temporal and spectral properties of the responses compared to the uncorrected system, and, furthermore, the obtained correction filter has a low level of pre-ringing.

  • 104.
    Lingvall, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signal Processing.
    Olofsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Statistically motivated design of input signals for modern ultrasonic array systems2008In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 123, no 5, p. 2620-2630Article in journal (Refereed)
    Abstract [en]

    Modern array systems allow for excitation of separate elements using arbitrary wave forms. This is utilized in pulse compression and coded excitation techniques to improve the imaging performance. Such techniques are however somewhat inflexible since they use predefined excitation schemes. This paper presents a more flexible method for optimizing the input signals to an ultrasonic array in such a way that the scattering strengths at arbitrarily chosen control points in the insonified object can be estimated with as small an error as possible, measured with a mean squared error criteria. The statistically motivated method is based on a linear model of the array imaging system and the method takes into account both prior information regarding the scattering strengths and measurement errors. The input signals are found by using genetic optimization and are constrained to have finite duration and bounds on the maximum amplitudes. Different constellations of control points, and different signal-to-noise ratios, yield different excitation schemes. The design approach finds multiple selective focal laws when choosing relatively well separated control points and when the control points are closely spaced, the resulting excitations result in more diffuse fields. Because of the flexibility in choosing the control points, the design method will be useful when developing transmission schemes aiming at fast imaging of large image areas using few transmissions.

  • 105.
    Lingvall, Fredrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Olofsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Stepinski, Tadeusz
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Synthetic aperture imaging using sources with finite aperture-deconvolution of the spatial impulse response2003In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 114, no 1, article id 225Article in journal (Refereed)
    Abstract [en]

    A method for ultrasonic synthetic aperture imaging using finite-sized transducers is introduced that is based on a compact, linear, discrete model of the ultrasonic measurement system developed using matrix formalism. Using this model a time-domain algorithm for deconvolution of the transducer’s spatial impulse responses (SIRs) is developed that is based on a minimum mean square error (MMSE) criterion. The algorithm takes the form of a spatiotemporal filter that compensates for the SIRs associated with a finite-sized transducer at every point of the processed image. A major advantage of the proposed method is that it can be used for any transducer, provided that its associated SIRs are known. This is in contrast to the synthetic aperture focusing technique (SAFT), which treats the transducer as a point source. The performance of the method is evaluated with simulations and experiments, performed in water using a linear phased array. The results obtained using the proposed method are compared to those obtained with a classical time-domain SAFT algorithm. For a finite aperture source, it is clearly shown that the resolution obtained using the proposed method is superior to that obtained using the SAFT algorithm.

  • 106.
    Liu, Hao
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Finnveden, Svante
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Barbagallo, Mathias
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Lopez Arteaga, Ines
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Wave propagation in sandwich panels with a poroelastic core2014In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 135, no 5, p. 2683-2693Article in journal (Refereed)
    Abstract [en]

    Wave propagation in sandwich panels with a poroelastic core, which is modeled by Biot's theory, is investigated using the waveguide finite element method. A waveguide poroelastic element is developed based on a displacement-pressure weak form. The dispersion curves of the sandwich panel are first identified as propagating or evanescent waves by varying the damping in the panel, and wave characteristics are analyzed by examining their motions. The energy distributions are calculated to identify the dominant motions. Simplified analytical models are also devised to show the main physics of the corresponding waves. This wave propagation analysis provides insight into the vibro-acoustic behavior of sandwich panels lined with elastic porous materials.

  • 107.
    Ljunggren, Fredrik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Changed sound properties due to minor construction changes in a lightweight building2008In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 123, no 5, p. 3763-Article in journal (Other academic)
    Abstract [en]

    This paper relates to building acoustic measurement inside a two-story office house. The construction, which is known as lightweight, is prefabricated in volumes at a factory and is then transported to the building yard for assembling. It is build up of a wooden frame with particle boards and plaster boards attached. The building consists of a number of nominally, or almost nominally, identical rooms with assumed identical sound properties. In the projection stage, the construction was slightly modified in some of the rooms in order to see in what way the sound properties would be affected. In total eight impact sound pressure level measurements and eight sound reduction index measurements were performed and analysed for the different setups.

  • 108.
    Lundén, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Hållbar Samhällsbyggnad, Ljud och vibration.
    Aircraft noise and speech intelligibility in an outdoor living space2014In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 135, no 6, p. 3455-3462Article in journal (Refereed)
  • 109. Luts, Heleen
    et al.
    Eneman, Koen
    Wouters, Jan
    Schulte, Michael
    Vormann, Matthias
    Buechler, Michael
    Dillier, Norbert
    Houben, Rolph
    Dreschler, Wouter A.
    Froehlich, Matthias
    Puder, Henning
    Grimm, Giso
    Hohmann, Volker
    Leijon, Arne
    KTH, School of Electrical Engineering (EES), Sound and Image Processing.
    Lombard, Anthony
    Mauler, Dirk
    Spriet, Ann
    Multicenter evaluation of signal enhancement algorithms for hearing aids2010In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 127, no 3, p. 1491-1505Article in journal (Refereed)
    Abstract [en]

    In the framework of the European HearCom project, promising signal enhancement algorithms were developed and evaluated for future use in hearing instruments. To assess the algorithms' performance, five of the algorithms were selected and implemented on a common real-time hardware/software platform. Four test centers in Belgium, The Netherlands, Germany, and Switzerland perceptually evaluated the algorithms. Listening tests were performed with large numbers of normal-hearing and hearing-impaired subjects. Three perceptual measures were used: speech reception threshold (SRT), listening effort scaling, and preference rating. Tests were carried out in two types of rooms. Speech was presented in multitalker babble arriving from one or three loudspeakers. In a pseudo-diffuse noise scenario, only one algorithm, the spatially preprocessed speech-distortion-weighted multi-channel Wiener filtering, provided a SRT improvement relative to the unprocessed condition. Despite the general lack of improvement in SRT, some algorithms were preferred over the unprocessed condition at all tested signal-to-noise ratios (SNRs). These effects were found across different subject groups and test sites. The listening effort scores were less consistent over test sites. For the algorithms that did not affect speech intelligibility, a reduction in listening effort was observed at 0 dB SNR. (C) 2010 Acoustical Society of America. [DOI: 10.1121/1.3299168]

  • 110.
    Mace, P.R.
    et al.
    Institute of Sound and Vibration Research, University of Southampton.
    Jones, Richard W.
    Luleå tekniska universitet.
    Harland, N.R.
    Department of Mechanical Engineering, University of Auckland.
    Wave transmission through structural inserts2001In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 109, no 4, p. 1417-1421Article in journal (Refereed)
    Abstract [en]

    The transmission of waves through two discontinuities in a one-dimensional waveguide system is considered. Attention is focused on transmission through a structural insert, which is defined here to be a waveguide segment which is inserted into an otherwise continuous structural member with different properties. A general expression for the net transmission through the insert is found. It has bandpass/stop characteristics and its frequency average is somewhat greater than that normally assumed due to the coherent interaction of the waves in the insert. The particular case is then considered where the insert comprises a three-layer composite beam inserted in a thin beam which vibrates in bending. The composite beam comprises two elastic faceplates and a core filled with a tunable electro- or magneto-rheological fluid. The net transmission and the stop bands depend on the properties of the insert. Since these properties are tunable by adjusting the field to which the tunable fluid is exposed, then so too are the transmission characteristics of the insert

  • 111.
    Madison, Guy
    et al.
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Paulin, Johan
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Ratings of speed in real music as a function of both original and manipulated tempo2010In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 128, no 5, p. 3032-3040Article in journal (Refereed)
    Abstract [en]

    There is an apparent contradiction between the narrow range of tempi optimal for perceptualjudgment and motor synchronization and the wide range of beat tempi found in real music. Therelation between listeners’ perception of speed and beat tempo was therefore investigated, both forreal music excerpts (ME) and metronome sequences. Tempi ranged from 42 to 200 beats per minute (BPM), and some excerpts were further tempo manipulated in four levels from from ±5 to ±20%. Regression analyses showed that speed was a shallower function of original tempo for fast (> 150 BPM) and slow (< 95 BPM) MEs than for MEs with intermediate tempi, describing anon-linear, sigmoid function. Manipulated tempo had twice as large an effect on speed as hadoriginal tempo. In contrast, speed was an almost linear function of tempo for metronome sequences.Taken together, these results show that the non-linearity stems from properties of the musical signal,rather than being a subjective perceptual effect. They indicate an inverse relation between tempo andrelative event density in real music, and demonstrate that the perception of periodic signals isaffected not only by the beat level, but also by faster and slower levels.© 2010 Acoustical Society of America.

  • 112.
    Mecke, Ann-Christine
    et al.
    KTH, School of Computer Science and Communication (CSC), Speech, Music and Hearing, TMH.
    Sundberg, Johan
    KTH, School of Computer Science and Communication (CSC), Speech, Music and Hearing, TMH.
    Gender differences in children's singing voices: Acoustic analyses and results of a listening test2010In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 127, no 5, p. 3223-3231Article in journal (Refereed)
    Abstract [en]

    This study tested the hypothesis that acoustic parameters exist which are specific to gender in children's singing voices, and that these parameters are relevant to listeners' identification of gender of children's singing voices. A listening test was run with examples of singing produced by children belonging to different singing cultures, six boys and six girls from a Swedish music school and six boys from an elite German boys' choir. Sustained vowels were analyzed with regard to formants and voice source properties (jitter, shimmer and glottal-to-noise-excitation rate, closed quotient, and normalized amplitude quotient). Most of the measured parameters differed significantly between the boys belonging to the two different singing cultures. Regarding boys and girls from the same choir, only the closed quotient and the fourth formant frequency differed significantly. The listening test was carried out by an expert panel. The listeners correctly identified the gender of the singer in 66.0% of the cases, i.e., far better than chance. A multiple linear regression analysis revealed that the listener's answers correlated well with the formant frequencies, with the fourth formant showing the highest correlation.

  • 113. Mecke, Ann-Christine
    et al.
    Sundberg, Johan
    KTH, School of Computer Science and Communication (CSC), Speech, Music and Hearing, TMH, Music Acoustics.
    Granqvist, Svante
    KTH, School of Computer Science and Communication (CSC), Speech, Music and Hearing, TMH, Music Acoustics.
    Echternach, Matthias
    Comparing closed quotient in children singers' voices as measured by high-speed-imaging, electroglottography and inverse filtering2012In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 131, no 1, p. 435-441Article in journal (Refereed)
    Abstract [en]

    The closed quotient, i.e., the ratio between the closed phase and the period, is commonly studied in voice research. However, the term may refer to measures derived from different methods, such as inverse filtering, electroglottography or high-speed digital imaging (HSDI). This investigation compares closed quotient data measured by these three methods in two boy singers. Each singer produced sustained tones on two different pitches and a glissando. Audio, electroglottographic signal (EGG), and HSDI were recorded simultaneously. The audio signal was inverse filtered by means of the DECAP program; the closed phase was defined as the flat minimum portion of the flow glottogram. Glottal area was automatically measured in the high speed images by the built-in camera software, and the closed phase was defined as the flat minimum portion of the area-signal. The EGG-signal was analyzed in four different ways using the MATLAB open quotient interface. The closed quotient data taken from the EGG were found to be considerably higher than those obtained from inverse filtering. Also, substantial differences were found between the closed quotient derived from HSDI and those derived from inverse filtering. The findings illustrate the importance of distinguishing between these quotients.

  • 114.
    Mihaescu, Mihai
    et al.
    Aerospace Engineering, University of Cincinnati.
    Khosla, Sid
    Otolaryngology, Head & Neck Surgery, University of Cincinnati-Medical Center.
    Murugappan, Shanmugam
    Otolaryngology, Head & Neck Surgery, University of Cincinnati-Medical Center.
    Gutmark, Ephraim
    Aerospace Engineering, University of Cincinnati.
    Unsteady laryngeal airflow simulations of the intra-glottal vortical structures2010In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 127, no 1, p. 435-444Article in journal (Refereed)
  • 115.
    Molin, Nils-Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Jansson, E.V.
    Kungliga tekniska högskolan, KTH.
    Transient wave propagation in wooden plates for musical instruments1989In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 85, no 5, p. 2179-2184Article in journal (Refereed)
    Abstract [en]

    Transient bending waves in three wooden plates are studied. A rectangular flat spruce plate (from a guitar top plate) and two arched violin plates (of spruce and maple, respectively) are impacted by a small ballistic pendulum. The impact point is at the center of the guitar plate and the bridge position of the violin plates. A sequence of holographic interferograms of the events is recorded using a double pulsed ruby laser as the light source. The holographic setup is a standard one. The elliptical shape of the interference fringes shows that wood is strongly anisotropic. The shape of the propagating pulse changes with time, which shows the dispersive behavior of bending waves in plates. A solution of the isotropic Euler plate equation for a flat plate is compared to experimental results of the guitar plate, assuming that this description is adequate along the main axes of this orthotropic plate. The shape of the propagating wave pattern and the elliptical rather than circular shape of the violin imply an interesting coincidence

  • 116.
    Molin, Nils-Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Lindgren, Lars-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Mechanics of Solid Materials.
    Jansson, Erik V.
    Royal Institute of Technology.
    Parameters of violin plates and their influence on the plate modes1988In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 83, no 1, p. 281-291Article in journal (Refereed)
    Abstract [en]

    Noncontact measuring methods and numerical calculations are used in a study of musical instruments. First, a simple method to determine the material parameters of a blank to a violin plate is presented. Eigenmodes of rectangular free-free violin wooden blanks are determined using optical nondestructive methods, Chladni patterns, or tapping. Assuming orthotropic material, the first three eigenmodes for such a blank are calculated using the finite element method (FEM). It is shown that the frequency of each eigenmode depends on separate elastic parameters. With this one variable dependence, it is a simple task to determine effective material parameters for quarter-cut standard wooden blanks when the frequencies and mass are known. Second, the violin maker's problem with the influence of material and geometrical parameters on the vibration modes is investigated. Numerical models and corresponding real violin plates are made from the spruce and the maple blanks. Good agreement between calculated and experimentally obtained plate modes is found. Calculations with a 10% variation in each parameter are thereafter used to give information about the influence of overall plate thickness variation, of local thickness variations, of changes in arch-height, and of material parameters. Third, boundary conditions for the plates when glued to the ribs are examined in a pilot experiment.

  • 117.
    Molin, Nils-Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Wåhlin, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Jansson, Erik V
    Kungliga tekniska högskolan, KTH.
    Transient wave response of the violin body revisited1991In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 90, no 4, p. 2192-2195Article in journal (Refereed)
    Abstract [en]

    In this investigation, the dispersive, transient wave propagation field of the top plate of a complete violin excited by a mechanically induced pulse at the top of the bridge is presented. A similar investigation has previously been made for excitation parallel with the top plate and is now completed with excitation perpendicular to the plate. From presented interferograms, it is seen that the top plate initially deforms in a nonsymmetric two-pole with centers at the two bridge feet. Shortly thereafter the two poles (valleys) are joined into one, but after 0.30 ms the displacement is still nonsymmetric with maximum motion at the bridge foot closest to the excitation point. From the measurements it can be concluded that for excitation parallel with the top plate, the plate between the f-holes acts mainly as a dipole, but with excitation perpendicular the same part acts mainly as a monopole. Thus the excitation of the top plate when playing the violin depends on the angle of the bow in relation to the top plate and should influence the tone character

  • 118.
    Molin, Nils-Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Wåhlin, Anders
    Jansson, E.V.
    Luleå tekniska universitet.
    Transient wave response of the violin body1990In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 88, no 5, p. 2479-2481Article in journal (Refereed)
    Abstract [en]

    In this investigation, the dispersive, transient wave propagation field of a complete violin excited by a mechanically induced impulse at the top of the bridge is presented. By means of double pulsed holographic interferometry with a ruby laser as light source the propagating wave field is recorded. From presented interferograms, it is seen that initially the top plate acts mainly as a nonsymmetric dipole with centers at the two bridge feet. The back plate is strongly coupled to the motion of the top plate by the sound post and acts more like a monopole. Thus the position of the sound post is crucial to the performance of the instrument. The free edges at the f-holes are very early reached by the dispersive bending waves of high amplitude probably giving a significant contribution to the sound of the violin family instruments

  • 119.
    Munhall, K. G.
    et al.
    Queen’s University, Kingston, Ontario, Canada .
    MacDonald, E. N.
    Queen’s University, Kingston, Ontario, Canada .
    Byrne, S. K.
    Queen’s University, Kingston, Ontario, Canada .
    Johnsrude, Ingrid
    Queen’s University, Kingston, Ontario, Canada .
    Talkers alter vowel production in response to real-time formant perturbation even when instructed not to compensate2009In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 125, no 1, p. 384-390Article in journal (Refereed)
    Abstract [en]

    Talkers show sensitivity to a range of perturbations of auditory feedback (e.g., manipulation of vocal amplitude, fundamental frequency and formant frequency). Here, 50 subjects spoke a monosyllable (“head”), and the formants in their speech were shifted in real time using a custom signal processing system that provided feedback over headphones. First and second formants were altered so that the auditory feedback matched subjects’ production of “had.” Three different instructions were tested: (1) control, in which subjects were naïve about the feedback manipulation, (2) ignore headphones, in which subjects were told that their voice might sound different and to ignore what they heard in the headphones, and (3) avoid compensation, in which subjects were informed in detail about the manipulation and were told not to compensate. Despite explicit instruction to ignore the feedback changes, subjects produced a robust compensation in all conditions. There were no differences in the magnitudes of the first or second formant changes between groups. In general, subjects altered their vowel formant values in a direction opposite to the perturbation, as if to cancel its effects. These results suggest that compensation in the face of formant perturbation is relatively automatic, and the response is not easily modified by conscious strategy.

  • 120.
    Neher, T
    et al.
    Eriksholm Research Centre, Oticon A/S, Snekkersten, Denmark.
    Lunner, Thomas
    Eriksholm Research Centre, Oticon A/S, Snekkersten, Denmark.
    Hopkins, K
    School of Psychological Sciences, University of Manchester, Manchester, United Kingdom.
    Moore, BC
    Department of Experimental Psychology, University of Cambridge, Cambridge, United Kingdom.
    Binaural temporal fine structure sensitivity, cognitive function, and spatial speech recognition of hearing-impaired listeners (L).2012In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 131, no 4, p. 2561-4Article in journal (Refereed)
    Abstract [en]

    The relationships between spatial speech recognition (SSR; the ability to understand speech in complex spatial environments), binaural temporal fine structure (TFS) sensitivity, and three cognitive tasks were assessed for 17 hearing-impaired listeners. Correlations were observed between SSR, TFS sensitivity, and two of the three cognitive tasks, which became non-significant when age effects were controlled for, suggesting that reduced TFS sensitivity and certain cognitive deficits may share a common age-related cause. The third cognitive measure was also significantly correlated with SSR, but not with TFS sensitivity or age, suggesting an independent non-age-related cause.

  • 121.
    Neher, Tobias
    et al.
    Eriksholm Research Centre, Oticon A/S, Snekkersten, Denmark.
    Lunner, Thomas
    Eriksholm Research Centre, Oticon A/S, Snekkersten, Denmark.
    Hopkins, Kathryn
    University of Manchester, United Kingdom .
    Moore, Brian C. J.
    University of Cambridge, United Kingdom .
    Binaural temporal fine structure sensitivity, cognitive function, and spatial speech recognition of hearing-impaired listeners (L)a)2012In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 131, no 4, p. 2561-2564Article in journal (Refereed)
    Abstract [en]

    The relationships between spatial speech recognition (SSR; the ability to understand speech in complex spatial environments), binaural temporal fine structure (TFS) sensitivity, and three cognitive tasks were assessed for 17 hearing-impaired listeners. Correlations were observed between SSR, TFS sensitivity, and two of the three cognitive tasks, which became non-significant when age effects were controlled for, suggesting that reduced TFS sensitivity and certain cognitive deficits may share a common age-related cause. The third cognitive measure was also significantly correlated with SSR, but not with TFS sensitivity or age, suggesting an independent non-age-related cause.

  • 122.
    Nilsson, A. C.
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Liu, B.
    Prediction of some vibro-acoustic properties of sandwich plates with honeycomb and foam cores2018In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 144, no 3, p. 1600-1614Article in journal (Refereed)
    Abstract [en]

    A sixth-order differential equation governing the flexural vibration of sandwich plates is derived. The sandwich plates considered consist of laminates bonded to honeycomb or foam cores. The structures are assumed to be symmetric. Shear and rotation in core are included in the model. The effect on the bending stiffness of rotation and shear in the core is discussed. Shear effects are of great importance, whereas rotation of the core has only a marginal effect on the bending stiffness of lightweight sandwich plates. The bending stiffness of a sandwich plate is found to strongly depend on frequency. The bending stiffness of a structure determines its acoustical coupling to any surrounding fluid and thus its sound transmission loss and sound radiation ratio. Loss factors of sandwich plates are discussed. Boundary conditions are formulated for rectangular plates having simply supported, clamped, or free edges. There are five boundary conditions to be satisfied at each edge of the plate. The bending stiffness of simply supported and infinite plates is presented as a function of frequency. Expressions for the point mobility for infinite or simply supported finite panels are given.

  • 123.
    Nilsson, Mats E.
    Stockholm University, Faculty of Social Sciences, Department of Psychology, Perception and psychophysics.
    Learning to extract a large inter-aural level difference in lag clicks2018In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 143, no 6, p. EL456-EL462Article in journal (Refereed)
    Abstract [en]

    Many blind people learn to use sound reflections to localize objects. However, precedence-effect research has reported evidence both for and against the possibility to improve lateralization of lag clicks preceded by lead clicks. This training study used stimuli more relevant to human echolocation than did previous training studies. One participant, the author, practiced lateralizing a lag-click inter-aural level difference (ILD) of 10 dB for 60 days, with performance measured in the lag-lead peak amplitude ratio at threshold. Clear improvements were observed at interclick intervals of 2-18 ms, suggesting that extracting a large lag-click ILD may improve with practice.

  • 124.
    Nilsson, Mats E.
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Tirado, Carlos
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Szychowska, Malina
    Stockholm University, Faculty of Social Sciences, Department of Psychology.
    Psychoacoustic evidence for stronger discrimination suppression of spatial information conveyed by lag-click interaural time than interaural level differences2019In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 145, no 1, p. 512-524Article in journal (Refereed)
    Abstract [en]

    Listeners have limited access to spatial information in lagging sound, a phenomenon known as discrimination suppression. It is unclear whether discrimination suppression works differently for interaural time differences (ITDs) and interaural level differences (ILDs). To explore this, three listeners assessed the lateralization (left or right) and detection (present or not) of lag clicks with a large fixed ITD (350 mu s) or ILD (10 dB) following a diotic lead click, with inter-click intervals (ICIs) of 0.125-256 ms. Performance was measured on a common scale for both cues: the lag-lead amplitude ratio [dB] at 75% correct answers. The main finding was that the lateralization thresholds, but not detection thresholds, were more strongly elevated for ITD-only than ILD-only clicks at intermediate ICIs (1-8 ms) in which previous research has found the strongest discrimination suppression effects. Altogether, these findings suggest that discrimination suppression involves mechanisms that make spatial information conveyed by lag-click ITDs less accessible to listeners than spatial information conveyed by lag-click ILDs.

  • 125.
    Nordqvist, Peter
    et al.
    KTH, Superseded Departments, Speech, Music and Hearing.
    Leijon, Arne
    KTH, Superseded Departments, Speech, Music and Hearing.
    An efficient robust sound classification algorithm for hearing aids2004In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 115, no 6, p. 3033-3041Article in journal (Refereed)
    Abstract [en]

    An efficient robust sound classification algorithm based on hidden Markov models is presented. The system would enable a hearing aid to automatically change its behavior for differing listening environments according to the user's preferences. This work attempts to distinguish between three listening environment categories: speech in traffic noise, speech in babble, and clean speech, regardless of the signal-to-noise ratio. The classifier uses only the modulation characteristics of the signal. The classifier ignores the absolute sound pressure level and the absolute spectrum shape, resulting in an algorithm that is robust against irrelevant acoustic variations. The measured classification hit rate was 96.7%-99.5% when the classifier was tested with sounds representing one of the three environment categories included in the classifier. False-alarm rates were 0.2%-1.7% in these tests. The algorithm is robust and efficient and consumes a small amount of instructions and memory. It is fully possible to implement-the classifier in a DSP-based hearing instrument.

  • 126.
    Nordqvist, Peter
    et al.
    KTH, Superseded Departments, Speech, Music and Hearing.
    Leijon, Arne
    KTH, Superseded Departments, Speech, Music and Hearing.
    Hearing-aid automatic gain control adapting to two sound sources in the environment, using three time constants2004In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 116, no 5, p. 3152-3155Article in journal (Refereed)
    Abstract [en]

    A hearing aid AGC algorithm is presented that uses a richer representation of the sound environment than previous algorithms. The proposed algorithm is designed to (1) adapt slowly (in approximately 10 s) between different listening environments, e.g., when the user leaves a single talker lecture for a multi-babble coffee-break; (2) switch rapidly (about 100 ms) between different dominant sound sources within one listening situation, such as the change from the user's own voice to a distant speaker's voice in a quiet conference room; (3) instantly reduce gain for strong transient sounds and then quickly return to the previous gain setting; and (4) not change the gain in silent pauses but instead keep the gain setting of the previous sound source. An acoustic evaluation showed that the algorithm worked as intended. The algorithm was evaluated together with a reference algorithm in 4 pilot field test. When evaluated by nine users in a set of speech recognition tests, the algorithm showed similar results to the reference algorithm.

  • 127. Noreland, Daniel
    et al.
    Udawalpola, Rajitha
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Scientific Computing. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Numerical Analysis.
    Berggren, Martin
    A hybrid scheme for bore design optimization of a brass instrument2010In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 128, p. 1391-1400Article in journal (Refereed)
  • 128.
    Noreland, Daniel
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Udawalpola, Rajitha
    Department of Information Technology, Uppsala University.
    Berggren, Martin
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    A hybrid scheme for bore design optimization of a brass instrument2010In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 128, no 3, p. 1391-1400Article in journal (Refereed)
    Abstract [en]

    Thispaper presents how the shape of a brass instrument canbe optimized with respect to its intonation properties. The instrumentis modeled using a hybrid method between a lossy one-dimensionaltransmission line analogy for the slowly flaring part of theinstrument, and a two-dimensional finite element model for the rapidlyflaring part. The optimization employs gradient-based algorithms, and allows fora large number of design variables. Through the use ofan appropriate choice of design variables, the algorithm is capableof rapidly finding horn profiles that are optimal subject tovarious geometric constraints, such as increasing or convex bell flares.It is found that under a convexity constraint, brass windbells that are optimal with respect to an intonation conditioncan be constructed of piecewise conical sections.

  • 129.
    Odelius, Johan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Johansson, Örjan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    The effect of binaural processing techniques on speech quality ratings of assistive listening devices in different room acoustics conditions2008In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 123, no 5, p. 3170-Article in journal (Other academic)
    Abstract [en]

    External microphone systems, referred to as assistive listening devices (ALD), are used in classrooms for hearing impaired students. The objective is to investigate the effect of binaural processing techniques in different room acoustic conditions. A listening experiment was conducted with 10 normal hearing adults. Response variables were judgements of clarity, pleasantness, listening effort and overall speech quality. Design variables were binaural processing, room acoustics and ALD bandwidth. Stimuli were generated using the room acoustic modelling software CATT Acoustic. Three speech sources, two male voices and one female voice, were placed at a table in the centre of a room and one Brown noise source was placed in one corner of the room. Microphones were placed 0.5 m in front of each speech source. Target source was a random choice of one of the two male voices. The binaural processing was utilized by a simple HRTF filtering. Depending on the angle to the source from a fictitious listening position at the table, corresponding interaural time difference (ITD) and the interaural level difference (ILD) was applied to the signal. Stimuli were presented by loudspeakers using cross-talk cancellation. The hypothesis is that binaural processing will give a significant improvement in speech quality.

  • 130.
    Olofsson, Tomas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Stepinski, Tadeusz
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Signals and Systems Group.
    Minimum entropy deconvolution of attenuated pulse-echo signals2001In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 109, no 6, p. 2831-2839Article in journal (Refereed)
  • 131. Olsson, Peter
    Acoustic scattering by a rigid movable body immersed in a fluid1985In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 78, no 6, p. 2132-2138Article in journal (Refereed)
  • 132. Olsson, Peter
    Scattering of elastic waves by a smooth rigid movable inclusion1986In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 79, no 5, p. 1237-1247Article in journal (Refereed)
  • 133. Olsson, Peter
    The acoustic limit in the null field approach to elastodynamic scattering1986In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 80, no 1, p. 317-324Article in journal (Refereed)
  • 134.
    Parra Martinez, Juan Pablo
    et al.
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Dazel, Olivier
    LAUM UMR CNRS 6613.
    Göransson, Peter
    KTH, School of Engineering Sciences (SCI), Centres, VinnExcellence Center for ECO2 Vehicle design. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Cuenca, Jacques
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL. Siemens Industry Software.
    Derivation of the state matrix for dynamic analysis of linear homogeneous media2016In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 140, no 2, p. EL218-EL220Article in journal (Refereed)
    Abstract [en]

    A method to obtain the state matrix of an arbitrary linear homogeneous medium excited by a plane wave is proposed. The approach is based on projections on the eigenspace of the governing equations matrix. It is an alternative to manually obtaining a linearly independent set of equations by combining the governing equations. The resulting matrix has been validated against previously published derivations for an anisotropic poroelastic medium.

  • 135.
    Pecorari, Claudio
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Adhesion and nonlinear scattering by rough surfaces in contact: Beyond the phenomenology of the Preisach-Mayergoyz framework2004In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 116, no 4, p. 1938-1947Article in journal (Refereed)
    Abstract [en]

    Phenomenological models reproducing the elasticity and acoustic properties of geomaterials and materials with damage have been successfully developed. These models yield macroscopic stress-strain constitutive equations featuring hysteresis with end-point memory, and predict the efficient generation of higher harmonics accompanying the propagation of monochromatic waves. The assumption common to these models is that the material's microstructure is characterized by nonlinear compliant components of an unspecified nature which can exist in two states: "open" or "closed." The density of the compliant units is defined on a mathematical continuum (the Preisach-Mayergoyz space) whose elements identify the dynamic behavior of the components. In this work, adhesion is shown to introduce hysteresis with end-point memory in the macroscopic behavior of an interface between two rough surfaces in contact, and, upon scattering, to generate higher harmonics bearing a striking similarity to those observed in wave propagation phenomena in media with distributed damage and in geomaterials. It appears, therefore, that two rough surfaces interacting via adhesion forces offer a meaningful example of macroscopic interface or bond with dynamics resembling that of the fictitious elements of the Preisach-Mayergoyz space, and acoustic nonlinear properties similar to those of rocks and damaged materials.

  • 136.
    Pecorari, Claudio
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Grishenkov, Dmitry
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Characterization of ultrasound-induced fracture of polymer-shelled ultrasonic contrast agents by correlation analysis2007In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 122, no 4, p. 2425-2430Article in journal (Refereed)
    Abstract [en]

    Beyond a characteristic value of the negative peak pressure, ultrasound fracture the shell of ultrasonic contrast agents (UCAs). Existing criteria for ascertaining this threshold value exploit the dependence of the amplitude of the UCA acoustic response on the incident pressure. However, under the common experimental conditions used in this work, these criteria appear to be unreliable when they are applied to UCAs that are stabilized by a thick polymeric shell. An alternative criterion for determining the onset of shell fracture is introduced here, which uses variations of the shape of the acoustic time-domain response of an UCA suspension. Experimental evidence is presented that links the changes of the cross-correlation coefficient between consecutive time-domain signals to the fracture of the shells, and consequent release of air microbubbles. In principle, this criterion may be used to characterize similar properties of other types of particles that cannot undergo inertial cavitation.

  • 137.
    Pecorari, Claudio
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Poznic, Milan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Nonlinear acoustic scattering by a partially closed surface-breaking crack2005In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 117, no 2, p. 592-600Article in journal (Refereed)
    Abstract [en]

    A theoretical model describing the nonlinear scattering of acoustic waves by surface-breaking cracks with faces in partial contact is presented. The nonlinear properties of the crack are accounted for by suitable boundary conditions that are derived from micromechanical models of the dynamics of elastic rough surfaces in contact. Both linear and nonlinear responses of the crack are shown to be largest for a shear vertical wave incident on the surface containing the crack at an angle just above the critical angle for longitudinal waves. These findings question the fitness for the purpose of a conventional inspection method, which utilizes shear vertical waves at 45degrees of incidence to search for surface-breaking cracks in many engineering components. For angles of incidence proximal to the critical angle of longitudinal waves, the efficiency of the second harmonic's generation appears to be the highest. Thanks to the increased sensitivity to surface-breaking cracks, this configuration seems to offer a solution to the localization problem, a task that has eluded nonlinear techniques operating under other circumstances. Finally, this model suggests a simple interpretation of the highly localized nonlinear response of delaminations in composite materials.

  • 138.
    Pedersen, Eja
    et al.
    Department of Environmental Medicine, Göteborg University, Göteborg, Sweden.
    Persson Waye, Kerstin
    Department of Environmental Medicine, Göteborg University, Göteborg, Sweden.
    Perception and annoyance due to wind turbine noise: a dose–response relationship2004In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 116, no 6, p. 3460-3470Article in journal (Refereed)
    Abstract [en]

    Installed global wind power increased by 26% during 2003, with U.S and Europe accounting for 90% of the cumulative capacity. Little is known about wind turbines' impact on people living in their vicinity. The aims of this study were to evaluate the prevalence of annoyance due to wind turbine noise and to study dose–response relationships. Interrelationships between noise annoyance and sound characteristics, as well as the influence of subjective variables such as attitude and noise sensitivity, were also assessed. A cross-sectional study was performed in Sweden in 2000. Responses were obtained through questionnaires (n = 351; response rate 68.4%), and doses were calculated as A-weighted sound pressure levels for each respondent. A statistically significant dose–response relationship was found, showing higher proportion of people reporting perception and annoyance than expected from the present dose–response relationships for transportation noise. The unexpected high proportion of annoyance could be due to visual interference, influencing noise annoyance, as well as the presence of intrusive sound characteristics. The respondents' attitude to the visual impact of wind turbines on the landscape scenery was found to influence noise annoyance.

  • 139.
    Pedersen, Eja
    et al.
    Halmstad University, School of Business and Engineering (SET), Biological and Environmental Systems (BLESS).
    van den Berg, Frits
    University of Groningen and GGD Amsterdam, The Netherlands.
    Bakker, Roel
    University Medical Centre Groningen, University of Groningen.
    Bouma, Jelte
    University Medical Centre Groningen, University of Groningen.
    Response to noise from modern wind farms in The Netherlands2009In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 126, no 2, p. 634-643Article in journal (Refereed)
    Abstract [en]

    The increasing number and size of wind farms call for more data on human response to wind turbine noise, so that a generalized dose-response relationship can be modeled and possible adverse health effects avoided. This paper reports the results of a 2007 field study in The Netherlands with 725 respondents. A dose-response relationship between calculated A-weighted sound pressure levels and reported perception and annoyance was found. Wind turbine noise was more annoying than transportation noise or industrial noise at comparable levels, possibly due to specific sound properties such as a "swishing" quality, temporal variability, and lack of nighttime abatement. High turbine visibility enhances negative response, and having wind turbines visible from the dwelling significantly increased the risk of annoyance. Annoyance was strongly correlated with a negative attitude toward the visual impact of wind turbines on the landscape. The study further demonstrates that people who benefit economically from wind turbines have a significantly decreased risk of annoyance, despite exposure to similar sound levels. Response to wind turbine noise was similar to that found in Sweden so the dose-response relationship should be generalizable.

  • 140.
    Peplow, Andrew
    et al.
    KTH, Superseded Departments, Vehicle Engineering.
    Finnveden, Svante
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, MWL Structural and vibroacoustics.
    A super-spectral finite element method for sound transmission in waveguides2004In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 116, no 3, p. 1389-1400Article in journal (Refereed)
    Abstract [en]

    A super-spectral finite element method is developed for the study of acoustical wave propagation in nonuniform waveguides. The formulation is based on a finite-element approach using a mixture of high order element shape functions and wave solutions. The numerical method provides solutions to acoustic duct or fluid waveguide environments which may be divided into rectangular sectors. Examples of its use for infinite acoustic waveguides include sound transmission through large ambient density variations and propagation over a geometric stair-step perturbation. Computation of a trapped mode waveform due to a point volume source within a uniform waveguide is also presented.

  • 141. Pobloth, H.
    et al.
    Kleijn, W. Bastiaan
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Squared error as a measure of perceived phase distortion2003In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 114, no 2, p. 1081-1094Article in journal (Refereed)
    Abstract [en]

    Based on two well-known auditory models, it is investigated whether the squared error between an original signal and a phase-distorted signal is a perceptually relevant measure for distortions in the Fourier phase spectrum of periodic signals obtained from speech. Both the performance of phase vector quantizers and the direct relationship between the squared error and two perceptual distortion measures are studied. The results indicate that for small values the squared error correlates well to the perceptual measures. However, for large errors, an increase in squared error does not, on average, lead to an increase in the perceptual measures. Empirical rate-perceptual distortion curves and listening tests confirm that, for low to medium codebook sizes, the average perceived distortion does not decrease with increasing codebook size when the squared error is used as encoding criterion.

  • 142.
    Poll, Marijke Keus van de
    et al.
    Department of Building, Energy, and Environmental Engineering, University of Gävle.
    Carlsson, Johannes
    Chalmers University of Technology, Department of Civil and Environmental Engineering.
    Marsh, John E.
    School of Psychology, University of Central Lancashire.
    Ljung, Robert
    Department of Building, Energy, and Environmental Engineering, University of Gävle, University of Gävle.
    Odelius, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Operation, Maintenance and Acoustics.
    Schlittmeier, Sabine J.
    Work, Environmental and Health Psychology, Catholic University of Eichstätt-Ingolstadt.
    Sundin, Gunilla
    Akustikon Team in Norconsult AB.
    Sörqvist, Patrik
    Department of Building, Energy, and Environmental Engineering, University of Gävle, Centre for Built Environment, University of Gävle.
    Unmasking the effects of masking on performance: The potential of multiple-voice masking in the office environment2015In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 138, no 2, p. 807-816Article in journal (Refereed)
    Abstract [en]

    Broadband noise is often used as a masking sound to combat the negative consequences of background speech on performance in open-plan offices. As office workers generally dislike broadband noise, it is important to find alternatives that are more appreciated while being at least not less effective. The purpose of experiment 1 was to compare broadband noise with two alternatives - multiple voices and water waves - in the context of a serial short-term memory task. A single voice impaired memory in comparison with silence, but when the single voice was masked with multiple voices, performance was on level with silence. Experiment 2 explored the benefits of multiple-voice masking in more detail (by comparing one voice, three voices, five voices, and seven voices) in the context of word processed writing (arguably a more office-relevant task). Performance (i.e., writing fluency) increased linearly from worst performance in the one-voice condition to best performance in the seven-voice condition. Psychological mechanisms underpinning these effects are discussed

  • 143.
    Reinfeldt, Sabine
    et al.
    Chalmers University of Technology.
    Stenfelt, Stefan
    Linköping University, Department of Clinical and Experimental Medicine, Technical Audiology. Linköping University, Faculty of Health Sciences.
    Good, Tobias
    Chalmers University of Technology.
    Håkansson, Bo
    Chalmers University of Technology.
    Examination of bone-conducted transmission from sound field excitation measured by thresholds, ear-canal sound pressure, and skull vibrations2007In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 121, no 3, p. 1576-1587Article in journal (Refereed)
    Abstract [en]

    Bone conduction (BC) relative to air conduction (AC) sound field sensitivity is here defined as the perceived difference between a sound field transmitted to the ear by BC and by AC. Previous investigations of BC-AC sound field sensitivity have used different estimation methods and report estimates that vary by up to 20 dB at some frequencies. In this study, the BC-AC sound field sensitivity was investigated by hearing threshold shifts, ear canal sound pressure measurements, and skull bone vibrations measured with an accelerometer. The vibration measurement produced valid estimates at 400 Hz and below, the threshold shifts produced valid estimates at 500 Hz and above, while the ear canal sound pressure measurements were found erroneous for estimating the BC-AC sound field sensitivity. The BC-AC sound field sensitivity is proposed, by combining the present result with others, as frequency independent at 50 to 60 dB at frequencies up to 900 Hz. At higher frequencies, it is frequency dependent with minima of 40 to 50 dB at 2 and 8 kHz, and a maximum of 50 to 60 dB at 4 kHz. The BC-AC sound field sensitivity is the theoretical limit of maximum attenuation achievable with ordinary hearing protection devices. © 2007 Acoustical Society of America.

  • 144.
    Robert, Etienne
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Imani Jajarmi, Ramin
    KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Physics.
    Steibel, Markus
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Engvall, Klas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Acoustophoresis in gases: Effect of turbulence and geometrical parameters on separation efficiency2012In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 132, article id 1928Article in journal (Refereed)
    Abstract [en]

    Advanced particle manipulation techniques based on acoustophoresis have been developed in recent years, driven by biomedical applications in liquid phase microfluidics systems. The same underlying physical phenomena are also encountered in gases and hold great potential for novel particle separation and sorting techniques aimed at industrial and scientific applications. However, considering the physical properties of gases, optimizing the performance of flow-through separators unavoidably requires an understanding of the re-mixing effect of turbulence. In the work presented here we have investigated the effect of turbulence intensity on the separation efficiency of a variable frequency acoustic particle separator featuring a rectangular cross-section with adjustable height. This allows the creation of a standing wave with a variable frequency and number of nodes. The air flow is seeded with alumina particles, 300 nm nominal diameter, and the excitation source is an electrostatic transducer operated in the 50-100 kHz range. In addition to flow and acoustic parameters, the separation efficiency is investigation as a function of geometric parameters such as the parallelism of the resonator walls and the matching between the channel height and the excitation frequency. The measurements made using laser doppler anemometry and light scattering provide guidance for the design of separator configurations capable of advanced separation and sorting tasks with sub-micron particles

  • 145. Roers, Friederike
    et al.
    Muerbe, Dirk
    Sundberg, Johan
    KTH, School of Computer Science and Communication (CSC), Speech, Music and Hearing, TMH.
    Voice classification and vocal tract of singers: A study of x-ray images and morphology2009In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 125, no 1, p. 503-512Article in journal (Refereed)
    Abstract [en]

    This investigation compares vocal tract dimensions and the classification of singer voices by examining an x-ray material assembled between 1959 and 1991 of students admitted to the solo singing education at the University of Music, Dresden, Germany. A total of 132 images were available to analysis. Different classifications' values of the lengths of the total vocal tract, the pharynx, and mouth cavities as well as of the relative position of the larynx, the height of the palatal arch, and the estimated vocal fold length were analyzed statistically, and some significant differences were found. The length of the pharynx cavity seemed particularly influential on the total vocal tract length, which varied systematically with classification. Also studied were the relationships between voice classification and the body height and weight and the body mass index. The data support the hypothesis that there are consistent morphological vocal tract differences between singers of different voice classifications.

  • 146.
    Romero, Jose
    et al.
    Laboratory of Acoustics, Department of Applied Physics, University of Valencia.
    Jimenez, Alicia
    Polytecnic University of Valencia.
    Sanchis, Antonio
    Polytecnic University of Valencia.
    Marin, Albert
    Polytecnic University of Valencia.
    Garcia, Amando
    Laboratory of Acoustics, Department of Applied Physics, University of Valencia.
    Villarroel, Grover Zurita
    Luleå tekniska universitet.
    Multivariate analysis of road traffic noise in Gandia (Spain) during 24 hours and its evolution in the last decades1998In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 103, no 5, p. 3003-Article in journal (Other academic)
    Abstract [en]

    Road traffic noise is one of the most widespread and growing problems in urban areas. While it has long been known that hearing can be damaged by exposure to noise, it is also believed that continual noise, even at low or moderate intensity, can cause psychological discomfort and sleep disorders. Traffic noise levels in urban areas are increasing, and the areas affected by noise are spreading. As a result of these problems, legislation has been introduced by the city council to control the noise produced by individual vehicles with the aim of eventually producing traffic noise levels which are acceptable to the public. In this paper, therefore, aspects which connect the evolution of the road traffic noise in the last decades and the development of the infrastructure of the city are discussed. The study was carried out in Gandia (Spain), which is situated on the East Coast of the country, 65 kms from Valencia and 100 kms from Benidorn. The population has increased from 50 000 to 60 000 in the last 15 years, and the traffic distribution of the city has changed during this time, with a new bridge and some highways around the urban area. The main objective of this paper is to characterize the effects of the road traffic noise during 24 h (between 1983 and 1997), and including such aspects as traffic density and psychological aspects. The analysis part was performed by using multivariate analysis methods (MVA). Multivariate analysis methods can be used to investigate relationships between all the variables by extracting information from data with many variables and treating them simultaneously.

  • 147. Rossing, T D
    et al.
    Sundberg, Johan
    KTH, School of Electrical Engineering and Computer Science (EECS), Speech, Music and Hearing, TMH, Music Acoustics.
    Ternström, Sten
    KTH, School of Computer Science and Communication (CSC), Speech, Music and Hearing, TMH, Music Acoustics.
    Acoustic comparison of soprano solo and choir singing.1987In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 82, no 3, p. 830-836Article in journal (Refereed)
    Abstract [en]

    Five soprano singers were recorded while singing similar texts in both choir and solo modes of performance. A comparison of long-term-average spectra of similar passages in both modes indicates that subjects used different tactics to achieve somewhat higher concentrations of energy in the 2- to 4-kHz range when singing in the solo mode. It is likely that this effect resulted, at least in part, from a slight change of the voice source from choir to solo singing. The subjects used slightly more vibrato when singing in the solo mode.

  • 148. Rossing, T D
    et al.
    Sundberg, Johan
    KTH, School of Electrical Engineering and Computer Science (EECS), Speech, Music and Hearing, TMH, Music Acoustics.
    Ternström, Sten
    Acoustic comparison of voice use in solo and choir singing.1986In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 79, no 6, p. 1975-1981Article in journal (Refereed)
    Abstract [en]

    An experiment was carried out in which eight bass/baritone singers were recorded while singing in both choral and solo modes. Together with their own voice, they heard the sound of the rest of the choir and a piano accompaniment, respectively. The recordings were analyzed in several ways, including computation of long-time-average spectra for each passage, analysis of the sound levels in the frequency ranges corresponding to the fundamental and the "singer's formant," and a comparison of the sung levels with the levels heard by the singers. Matching pairs of vowels in the two modes were inverse filtered to determine the voice source spectra and formant frequencies for comparison. Differences in both phonation and articulation between the two modes were observed. Subjects generally sang with more power in the singer's formant region in the solo mode and with more power in the fundamental region in the choral mode. Most singers used a reduced frequency distance between the third and fifth formants for increasing the power in the singer's formant range, while the difference in the fundamental was mostly a voice source effect. In a choral singing mode, subjects usually adjusted their voice levels to the levels they heard from the other singers, whereas in a solo singing mode the level sung depended much less on the level of an accompaniment.

  • 149.
    Rossing, Thomas D.
    et al.
    Northern Illinois University.
    Molin, Nils-Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Runnemalm, Anna
    Luleå tekniska universitet.
    Modal analysis of violin bodies viewed as three-dimensional structures2003In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 114, no 4, p. 2438-Article in journal (Refereed)
    Abstract [en]

    Modal analyses of violins show several strong modes in the low frequency range. Holographic interferograms suggest that four strong modes can be interpreted as doublets having two and three nodal planes that intersect a cylinder with a roughly elliptical cross section at the bridge [A. Runnemalm, N.-E. Molin, and E. Jansson, J. Acoust. Soc. Am. 107, 3452-3459 (2000); M. Roberts and T. D. Rossing, Catgut Acoust. Soc. J. 3, 9-15 (1998)]. This is especially clear when the instrument is viewed simultaneously from three sides using mirrors, and the holographic system is made sensitive to in-plane motion as well. These doublets are not unlike those observed in cylindrical vibrators such as bells, and they remind us that a violin is a 3-dimensional object

  • 150.
    Rudenko, Oleg
    et al.
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    Hedberg, Claes
    Blekinge Institute of Technology, School of Engineering, Department of Mechanical Engineering.
    The phenomenon of self-trapping of a strongly nonlinear wave.2014In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 135, no 4Article in journal (Refereed)
    Abstract [en]

    Self means here an effect of a wave on itself. Several self-action phenomena are known in nonlinear wave physics. Among them are self-focusing of beams self-compression of light pulses self-channeling self-reflection (or self-splitting) waves with shock fronts self-induced transparency and self-modulation. These phenomena are known for weakly nonlinear waves of different physical origin. Our presentation at ASA meeting in Montreal [POMA 19 045080 (2013)] was devoted to strongly nonlinear waves having no transition to the linear limit at infinitesimally small amplitudes. Such waves can demonstrate particle-like properties. Self-trapping consists of the arrest of wave propagation and in the formation of a localized state. In particular the model generalizing the Heisenberg' ordinary differential equation to spatially distributed systems predicts periodic oscillations but no traveling waves. Different models for strongly nonlinear waves will be considered and some unusual phenomena will be discussed. Preliminary results were published in Ac. Phys. 59 584 (2013) and Physics-Uspekhi (Adv. Phys. Sci.) 183 683 (2013). [This work was supported by the Megagrant No.11.G34.31.066 (Russia) and the KK Foundation (Sweden).

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