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  • 51. Herbst, Christian T.
    et al.
    Ternström, Sten
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH, Musikakustik.
    Svec, Jan G.
    Investigation of four distinct glottal configurations in classical singing-A pilot study2009Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 125, nr 3, s. EL104-EL109Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study investigates four qualities of singing voice in a classically trained baritone: "naive falsetto," "countertenor falsetto," "lyrical chest" and "full chest." Laryngeal configuration and vocal fold behavior in these qualities were studied using laryngeal videostroboscopy, videokymography, electroglottography, and sound spectrography. The data suggest that the four voice qualities were produced by independently manipulating mainly two laryngeal parameters: (1) the adduction of the arytenoid cartilages and (2) the thickening of the vocal folds. An independent control of the posterior adductory muscles versus the vocalis muscle is considered to be the physiological basis for achieving these singing voice qualities.

  • 52.
    Häggblad, Jon
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Numerisk analys, NA.
    Engquist, Björn
    University of Texas.
    Consistent modeling of boundaries in acoustic finite-difference time-domain simulations2012Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 132, nr 3, s. 1303-1310Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The finite-difference time-domain method is one of the most popular for wave propagation in the time domain. One of its advantages is the use of a structured staggered grid, which makes it simple and efficient on modern computer architectures. A drawback however is the difficulty in approximating oblique boundaries, having to resort to staircase approximations.  In many scattering problems this means that the grid resolution required to obtain an accurate solution is much higher than what is dictated by propagation in a homogeneous material.  In this paper zero boundary data is considered, first for the velocity and then the pressure. These two forms of boundary conditions model perfectly rigid and pressure-release boundaries, respectively.  A simple and efficient method to consistently model curved rigid boundaries in two dimensions was developed in [A.-K. Tornberg and B. Engquist, J. Comput. Phys. 227, 6922--6943 (2008)].  Here this treatment is generalized to three dimensions.  Based on the approach of this method, a technique to model pressure-release surfaces with second order accuracy and without additional restriction on the timestep is also introduced.  The structure of the standard method is preserved, making it easy to use in existing solvers.  The effectiveness is demonstrated in several numerical tests.

  • 53.
    Johansson, Anders
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teknisk mekanik, Strömningsmekanik och Teknisk Akustik, Marcus Wallenberg Laboratoriet MWL.
    Bolin, Karl
    KTH, Skolan för teknikvetenskap (SCI), Teknisk mekanik, Strömningsmekanik och Teknisk Akustik, Marcus Wallenberg Laboratoriet MWL.
    Analysis of landing noise from Airbus A321neo using long term noise measurements and flight recorder data2023Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 153, nr 6, s. 3482-3492Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This article analyzes aircraft noise measurements from the Airbus A321neo at 7.5 and 5 nautical miles from the runway threshold. Using correlation, analysis of variance, and hierarchical regression analysis, we assessed the influence of flight data recorder variables and meteorological parameters on the measured sound level variations. A combination of aircraft speed and configuration of the high lift devices can predict approximately 60% of the sound level variations. Sound level dependence on speed ranges between 0.5 and 1.5 dB/10 kn for different configurations and landing gear deployment had a +3 dB impact on sound levels. At the same time, weather and wind conditions accounted for a relatively small proportion of the variation. Overall, this study sheds light on the factors contributing to aircraft noise during the final approach and provides insights into potential noise reduction strategies.

  • 54.
    Kari, Leif
    KTH, Tidigare Institutioner (före 2005), Farkostteknik.
    On the dynamic stiffness of preloaded vibration isolators in the audible frequency range: Modeling and experiments2003Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 113, nr 4, s. 1909-1921Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The nonlinear, preload-dependent dynamic stiffness of a cylindrical vibration isolator is examined via measurements and modeling within an audible frequency range covering 50 to 1000 Hz at various preloads. The stiffness is found to depend strongly on frequency-resulting in peaks and troughs, and on preload-particularly above 500 Hz. The problems of simultaneously modeling the rubber prestrain dependence and its audible short-term response are removed by adopting a nearly incompressible material model, being elastic in dilatation while displaying viscoelasticity in deviation. The latter exhibits a time strain separable relaxation tensor with a single function embodying its time dependence. This function is based on a continuous fractional order derivative model, the main advantage being the minimum number of parameters required to successfully model the rubber properties over a broad structure-borne sound frequency domain, while embodying a continuous distribution of relaxation time. The weak formulations corresponding to the stiffness problem are solved by an updated Lagrangian nonlinear finite-element procedure. The model and measurement results agree strikingly well with static and dynamic measurements throughout the whole frequency domain for the examined preloads.

  • 55.
    Karlsson, Mikael
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strömningsakustik.
    Glav, Ragnar
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Åbom, Mats
    KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    The Herschel-Quincke tube: The attenuation conditions and their sensitivity to mean flow2008Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 124, nr 2, s. 723-732Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The classic Herschel-Quincke tube is a parallel connection of two ducts yielding multiple noise attenuation maxima via destructive interference. This problem has been discussed to different degrees by a number of authors over the years. This study returns to the basics of the system for the purpose of furthering the understanding of the conditions necessary for noise attenuation and especially their sensitivity to mean flow. First, the transmission loss for an N-duct system with mean flow and arbitrary conditions of state in the different ducts is derived. Next, the two types of conditions yielding the attenuation maxima are studied. In addition to a discussion of the underlying physics, generic expressions for frequencies at which maximum attenuation occur are presented. Experiments without mean flow generally show good agreement with theory based on straight duct elements. However, more detailed models may be required for accurate simulations in the presence of mean flow. A simple model compensating for the losses associated with bends is shown to improve the results significantly for the geometry studied.

  • 56.
    Kierkegaard, Axel
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Boij, Susann
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Efraimsson, Gunilla
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Aeroakustik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW.
    A frequency domain linearized Navier-Stokes equations approach to acoustic propagation in flow ducts with sharp edges2010Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 127, nr 2, s. 710-719Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Acoustic wave propagation in flow ducts is commonly modeled with time-domain non-linear Navier-Stokes equation methodologies. To reduce computational effort, investigations of a linearized approach in frequency domain are carried out. Calculations of sound wave propagation in a straight duct are presented with an orifice plate and a mean flow present. Results of transmission and reflections at the orifice are presented on a two-port scattering matrix form and are compared to measurements with good agreement. The wave propagation is modeled with a frequency domain linearized Navier-Stokes equation methodology. This methodology is found to be efficient for cases where the acoustic field does not alter the mean flow field, i.e., when whistling does not occur.

  • 57.
    Koniaris, Christos
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Ljud- och bildbehandling.
    Kuropatwinski, Marcin
    KTH, Skolan för elektro- och systemteknik (EES), Ljud- och bildbehandling.
    Kleijn, Bastiaan
    KTH, Skolan för elektro- och systemteknik (EES), Ljud- och bildbehandling.
    Auditory-model based robust feature selection for speech recognition2010Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 127, nr 2, s. EL73-EL79Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

     It is shown that robust dimension-reduction of a feature set for speech recognition can be based on a model of the human auditory system. Whereas conventional methods optimize classification performance, the proposed method exploits knowledge implicit in the auditory periphery, inheriting its robustness. Features are selected to maximize the similarity of the Euclidean geometry of the feature domain and the perceptual domain. Recognition experiments using mel-frequency cepstral coefficients (MFCCs) confirm the effectiveness of the approach, which does not require labeled training data. For noisy data the method outperforms commonly used discriminant-analysis based dimension-reduction methods that rely on labeling. The results indicate that selecting MFCCs in their natural order results in subsets with good performance.

  • 58. Lehtonen, Heidi-Maria
    et al.
    Askenfelt, Anders
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH, Musikakustik.
    Valimaki, Vesa
    Analysis of the part-pedaling effect in the piano2009Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 126, nr 2, s. EL49-EL54Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This letter reports basic acoustic phenomena related to part-pedaling in the piano. With part-pedaling, the piano tone can be divided into three distinct time intervals: initial free vibration, damper-string interaction, and final free vibration. Varying the distance of the damper from the string, the acoustic signal and the damper acceleration were measured for several piano tones. During the damper-string interaction, the piano tone decay is rapid and the timbre of the tone is affected by the nonlinear amplitude limitation of the string motion. During the final free decay, the string continues to vibrate freely with a lower decay rate.

  • 59.
    Leijon, Arne
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Tal, musik och hörsel, TMH.
    Dahlquist, Martin
    Widex AS, ORCA Europe, Bjorns Tradgardsgrand 1, SE-11621 Stockholm, Sweden..
    Smeds, Karolina
    Widex AS, ORCA Europe, Bjorns Tradgardsgrand 1, SE-11621 Stockholm, Sweden..
    Bayesian analysis of paired-comparison sound quality ratings2019Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 146, nr 5, s. 3174-3183Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a method to analyze paired-comparison data including either binary or graded ordinal responses, with or without ties. The proposed method can use either of two classical choice models: (1) Thurstone case V, which assumes a Gaussian distribution of the sensory variables underlying listener decisions, or (2) the Bradley-Terry-Luce (BTL) model, which assumes a logistic distribution. The analysis method was validated using simulated paired-comparison experiments with known distributions of the sound-quality parameters in the simulated population from which "participants" were generated at random. The validation indicated that the Thurstone and BTL models give similar results close to the true values. The estimated credibility of a quality difference was slightly higher with the BTL model. The analysis results showed dramatically better precision when the response data included graded ordinal judgments instead of binary responses. Allowing tied responses also tended to improve precision. The method was also applied to data from a real evaluation of hearing-aid programs. The analysis revealed clinically interesting results with high statistical credibility, although the amount of test data was limited.

  • 60.
    Lind Nordgren, Eleonora
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Deü, Jean-Francois
    National Conservatory of Arts and Crafts, Laboratoire de Mécanique des Structures et des Systémes Couplés (LMSSC), Conservatoire National des Arts et Metiérs, France.
    Dazel, Olivier
    University of Maine, Laboratoire d'Acoustique de l'Université du Maine, France.
    Vibroacoustic response sensitivity due to relative alignment of two anisotropic poro-elastic layers2013Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 133, nr 5, s. EL426-EL430Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effects of relative alignment of two different types of anisotropic open cell porous materials are investigated in terms of the acoustic response of a multi-layered configuration. Numerical experiments, where gradient based optimization techniques were used, are conducted to find possible extremal values. It is shown that, depending on the degree of anisotropy of the porous material properties, their angular orientations have a significant and frequency dependent influence on the measured response. The results highlight the importance of further advancing the knowledge of anisotropic porous material behavior.

  • 61.
    Linne, Markus
    et al.
    Swedish Def Res Agcy, Underwater Technol, S-16490 Stockholm, Sweden..
    Sigray, Peter
    KTH, Skolan för teknikvetenskap (SCI), Teknisk mekanik, Farkostteknik och Solidmekanik.
    Lalander, Emilia
    Swedish Def Res Agcy, Underwater Technol, S-16490 Stockholm, Sweden..
    Davidsson, Per
    Swedish Def Res Agcy, Underwater Technol, S-16490 Stockholm, Sweden..
    Hall, Thomas
    Swedish Def Res Agcy, Underwater Technol, S-16490 Stockholm, Sweden..
    Ostberg, Martin
    Swedish Def Res Agcy, Underwater Technol, S-16490 Stockholm, Sweden..
    Development of calibration technique for underwater transducers in free field conditions below 1000 Hz with results on an acoustical recorder2022Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 152, nr 6, s. 3606-3615Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A calibration technique with potential for low frequencies and sizeable systems of underwater transducers is being developed at the Swedish Defence Research Agency. The technique is based on the three-transducer spherical wave reciprocity method for use in an ice-covered lake with a depth of 220 m in the Swedish arctic zone. The calibration is performed at a depth of approximately 100 m with inter-transducer separations of 50 m, 86.6 m, and 100 m, allowing for frequencies down to 59 Hz using time-gated tone burst signals. In this paper, the calibration location, system, and technique are introduced, and the calibration results of an acoustical recorder in the range of 59 Hz-1 kHz are presented. The sensitivity is varying with frequency around -148 dB re 1 V/mu Pa, and the uncertainty budget is discussed.

  • 62.
    Liu, Hao
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Finnveden, Svante
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Barbagallo, Mathias
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Lopez Arteaga, Ines
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Wave propagation in sandwich panels with a poroelastic core2014Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 135, nr 5, s. 2683-2693Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 63. 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, Skolan för elektro- och systemteknik (EES), Ljud- och bildbehandling.
    Lombard, Anthony
    Mauler, Dirk
    Spriet, Ann
    Multicenter evaluation of signal enhancement algorithms for hearing aids2010Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 127, nr 3, s. 1491-1505Artikkel i tidsskrift (Fagfellevurdert)
    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]

  • 64.
    Mecke, Ann-Christine
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH.
    Sundberg, Johan
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH.
    Gender differences in children's singing voices: Acoustic analyses and results of a listening test2010Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 127, nr 5, s. 3223-3231Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 65. Mecke, Ann-Christine
    et al.
    Sundberg, Johan
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH, Musikakustik.
    Granqvist, Svante
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH, Musikakustik.
    Echternach, Matthias
    Comparing closed quotient in children singers' voices as measured by high-speed-imaging, electroglottography and inverse filtering2012Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 131, nr 1, s. 435-441Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 66.
    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 structures2010Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 127, nr 1, s. 435-444Artikkel i tidsskrift (Fagfellevurdert)
  • 67.
    Nilsson, Anders Christian
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Liu, B.
    Prediction of some vibro-acoustic properties of sandwich plates with honeycomb and foam cores2018Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 144, nr 3, s. 1600-1614Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 68.
    Nordqvist, Peter
    et al.
    KTH, Tidigare Institutioner (före 2005), Tal, musik och hörsel.
    Leijon, Arne
    KTH, Tidigare Institutioner (före 2005), Tal, musik och hörsel.
    An efficient robust sound classification algorithm for hearing aids2004Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 115, nr 6, s. 3033-3041Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 69.
    Nordqvist, Peter
    et al.
    KTH, Tidigare Institutioner (före 2005), Tal, musik och hörsel.
    Leijon, Arne
    KTH, Tidigare Institutioner (före 2005), Tal, musik och hörsel.
    Hearing-aid automatic gain control adapting to two sound sources in the environment, using three time constants2004Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 116, nr 5, s. 3152-3155Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 70.
    Nyborg, Camilla Marie
    et al.
    Technical University of Denmark-DTU Wind Energy ,Frederiksborgvej 399.
    Bolin, Karl
    KTH, Skolan för teknikvetenskap (SCI), Teknisk mekanik, Strömningsmekanik och Teknisk Akustik, Marcus Wallenberg Laboratoriet MWL.
    Karasalo, Ilkka
    Fischer, Andreas
    Technical University of Denmark-DTU Wind Energy ,Frederiksborgvej 399.
    An inter-model comparison of parabolic equation methods for sound propagation from wind turbines2023Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 154, nr 2, s. 1299-1314Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The modeling of sound propagation for land-based wind turbines is a complex task that takes various parameters into account. Not only do the wind speed and wind direction affect the noise received at a certain position by changing the refraction of the sound, but also the terrain complexity, ground impedance, and receiver position relative to the source and ground all affect propagation. These effects are seen by the reflections of the sound at the ground surface causing interference of sound waves, or by the receiver being positioned in and out of noise shadow zones in the upwind far field position, or in steep terrain irregularities. Several sound propagation models with different levels of fidelity have been developed through time to account for these effects. This paper will focus on two different parabolic equation models, the Beilis-Tappert Parabolic Equation and the Generalized Terrain Parabolic Equation, through theoretical studies of varying terrain complexity, ground impedance, and sound speed profiles (upwind, downwind, and no wind). In addition, the propagation models are validated through spectral comparisons to noise measurements from two different campaigns considering loudspeaker noise and wind turbine noise, respectively.

  • 71.
    Parra Martinez, Juan Pablo
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Dazel, Olivier
    LAUM UMR CNRS 6613.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Cuenca, Jacques
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet. Siemens Industry Software.
    Derivation of the state matrix for dynamic analysis of linear homogeneous media2016Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 140, nr 2, s. EL218-EL220Artikkel i tidsskrift (Fagfellevurdert)
    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.

    Fulltekst (pdf)
    fulltext
  • 72.
    Pecorari, Claudio
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Adhesion and nonlinear scattering by rough surfaces in contact: Beyond the phenomenology of the Preisach-Mayergoyz framework2004Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 116, nr 4, s. 1938-1947Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 73.
    Pecorari, Claudio
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Grishenkov, Dmitry
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Characterization of ultrasound-induced fracture of polymer-shelled ultrasonic contrast agents by correlation analysis2007Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 122, nr 4, s. 2425-2430Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 74.
    Pecorari, Claudio
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Poznic, Milan
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Nonlinear acoustic scattering by a partially closed surface-breaking crack2005Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 117, nr 2, s. 592-600Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 75.
    Peplow, Andrew
    et al.
    KTH, Tidigare Institutioner (före 2005), Farkostteknik.
    Finnveden, Svante
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strukturakustik.
    A super-spectral finite element method for sound transmission in waveguides2004Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 116, nr 3, s. 1389-1400Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 76. Pobloth, H.
    et al.
    Kleijn, W. Bastiaan
    KTH, Tidigare Institutioner (före 2005), Signaler, sensorer och system.
    Squared error as a measure of perceived phase distortion2003Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 114, nr 2, s. 1081-1094Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 77.
    Robert, Etienne
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Imani Jajarmi, Ramin
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik.
    Steibel, Markus
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Engvall, Klas
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Kemisk teknologi.
    Acoustophoresis in gases: Effect of turbulence and geometrical parameters on separation efficiency2012Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 132, artikkel-id 1928Artikkel i tidsskrift (Fagfellevurdert)
    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

  • 78. Roers, Friederike
    et al.
    Muerbe, Dirk
    Sundberg, Johan
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH.
    Voice classification and vocal tract of singers: A study of x-ray images and morphology2009Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 125, nr 1, s. 503-512Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 79. Rossing, T D
    et al.
    Sundberg, Johan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Tal, musik och hörsel, TMH, Musikakustik.
    Ternström, Sten
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH, Musikakustik.
    Acoustic comparison of soprano solo and choir singing.1987Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 82, nr 3, s. 830-836Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 80. Rossing, T D
    et al.
    Sundberg, Johan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Tal, musik och hörsel, TMH, Musikakustik.
    Ternström, Sten
    Acoustic comparison of voice use in solo and choir singing.1986Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 79, nr 6, s. 1975-1981Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 81.
    Rumpler, Romain
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Deü, J.-F
    Conservatoire National des Arts et Métiers, Paris France.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    A modal-based reduction method for sound absorbing porous materials in poro-acoustic finite element models2012Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 132, nr 5, s. 3162-3179Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Structural-acoustic finite element models including three-dimensional (3D) modeling of porous media are generally computationally costly. While being the most commonly used predictive tool in the context of noise reduction applications, efficient solution strategies are required. In this work, an original modal reduction technique, involving real-valued modes computed from a classical eigenvalue solver is proposed to reduce the size of the problem associated with the porous media. In the form presented in this contribution, the method is suited for homogeneous porous layers. It is validated on a 1D poro-acoustic academic problem and tested for its performance on a 3D application, using a subdomain decomposition strategy. The performance of the proposed method is estimated in terms of degrees of freedom downsizing, computational time enhancement, as well as matrix sparsity of the reduced system.

  • 82.
    Rumpler, Romain
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    A finite element solution strategy based on Padé approximants for fast multiple frequency sweeps of coupled elastic, poroelastic, and internal acoustic problems2013Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 133, nr 5, s. 3241-3241Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Analyses involving structural-acoustic finite element models including three-dimensional modeling of porous media are, in general, computationally costly. While being the most commonly used predictive tool in the context of noise and vibrations reduction, efficient solution strategies enabling the handling of large-size multiphysics industrial problems are still lacking, particularly in the context where multiple frequency response estimations are required, e.g., for topology optimization, multiple load cases analysis, etc. In this work, an original solution strategy is presented for the solution of multi-frequency structural-acoustic problems including poroelastic damping. Based on the use of Padé approximants, very accurate interpolations of multiple frequency sweeps are performed, allowing for substantial improvements in terms of computational resources, i.e., time and memory allocation. The method is validated and demonstrated for its potential on 3D applications involving coupled elastic, poroelastic, and internal acoustic domains.

  • 83.
    Rumpler, Romain
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Comparison of the component-wise and projection-based Padé approximant methods for acoustic coupled problems2017Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 141, nr 5, s. 4033-4033Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Several Padé-based computational methods have been recently combined with the finite element method for the efficient solution of complex time-harmonic acoustic problems. Among these, the component-wise approach, which focuses on the fast-frequency sweep of individual degrees of freedom in the problem, is an alternative to the projection-based approaches. While the former approach allows for piecewise analytical expressions of the solution for targeted degrees of freedom, the projection-based approaches may offer a wider range of convergence. In this work, the two approaches are compared for a range of problems varying in complexity, size and physics. This includes for instance the modeling of coupled problems with non-trivial frequency dependence such as for the modeling of sound absorbing porous materials. Conclusions will be drawn in terms of computational time, accuracy, memory allocation, implementation, and suitability of the methods for specific problems of interest.

  • 84.
    Rumpler, Romain
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Numerisk akustik.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Numerisk akustik.
    Deü, Jean-Francois
    Conservatoire National des Arts et Métiers, Paris France.
    A residue-based mode selection and sorting procedure for efficient poroelastic modeling in acoustic finite element applications2013Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 134, nr 6, s. 4730-4741Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Analysis of three-dimensional sound propagation in porous elastic media with the Finite Element (FE) method is, in general, computationally costly. Although it is the most commonly used predictive tool in complex noise control applications, efficient FE solution strategies for large-size industrial problems are still lacking. In this work, an original procedure is proposed for the sorting and selection of the modes in the solution for the sound field in homogeneous porous domains. This procedure, validated on several 2D and 3D problems, enables to reduce the modal basis in the porous medium to its most physically significant components. It is shown that the size of the numerical problem can be reduced, together with matrix sparsity improvements, which lead to the reduction in computational time and enhancements in the efficacy of the acoustic response computation. The potential of this method for other industrial-based noise control problems is also discussed.

  • 85.
    Rumpler, Romain
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teknisk mekanik, Strömningsmekanik och Teknisk Akustik, Marcus Wallenberg Laboratoriet MWL.
    Venkataraman, Siddharth
    KTH, Skolan för teknikvetenskap (SCI), Teknisk mekanik, Strömningsmekanik och Teknisk Akustik, Marcus Wallenberg Laboratoriet MWL.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Teknisk mekanik, Strömningsmekanik och Teknisk Akustik, Marcus Wallenberg Laboratoriet MWL.
    Noise measurements as a proxy to evaluating the response to recommendations in times of crisis: An update analysis of the transition to the second wave of the CoViD-19 pandemic in Central Stockholm, Sweden2021Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 149, nr 3, s. 1838-1842Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sweden stands out among the other European countries by the degree of restrictive measures taken towards handling the 2019 coronavirus outbreak, associated with the CoViD-19 pandemic. While several governments have imposed a nationwide total or partial lockdown to slow down the spread of the virus, the Swedish government has opted for a recommendation-based approach together with a few imposed restrictions. In a previous contribution by the authors, the impact of the Swedish strategy was observed through the monitored variation of the city noise levels during a period associated with the so-called "first wave" of the pandemic in Stockholm. A very strong impact of these recommendations was shown on the evolution of the noise levels in central Stockholm. This highlighted the potential of acoustic sensor networks both for enforcement of regulation and monitoring of the effectiveness of their implementation. The present contribution presents a follow-up to this urban noise monitoring in central Stockholm, Sweden, for the period leading to the so-called "second wave" of the pandemic in Europe. Both the evolution of adherence to the recommendations and the impact of the recurrence of cases combined with reinforced recommendations are observed through the evolution of the measured noise levels. While the measurements show a gradual lower level of compliance, in particular, past the summer break, these also show again a rapid response to the reinforced recommendations issued by the authorities in mid-fall of 2020. These observations thus confirm the potential associated with detailed urban noise monitoring, for instance here acting as a proxy to evaluating the response to recommendations or restrictions in times of crisis.

  • 86. Ruty, N.
    et al.
    Pelorson, X.
    Van Hirtum, A.
    Lopez-Arteaga, Ines
    Eindhoven University of Technology.
    Hirschberg, A.
    An in vitro setup to test the relevance and the accuracy of low-order vocal folds models2007Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 121, nr 1, s. 479-490Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An experimental setup and human vocal folds replica able to produce self-sustained oscillations are presented. The aim of the setup is to assess the relevance and the accuracy of theoretical vocal folds models. The applied reduced mechanical models are a variation of the classical two-mass model, and a simplification inspired on the delayed mass model for which the coupling between the masses is expressed as a fixed time delay. The airflow is described as a laminar flow with flow separation. The influence of a downstream resonator is taken into account. The oscillation pressure threshold and fundamental frequency are predicted by applying a stability analysis to the mechanical models. The measured frequency response of the mechanical replica together with the initial (rest) area allows us to determine the model parameters (spring stiffness, damping, geometry, masses). Validation of theoretical model predictions to experimental data shows the relevance of low-order models in gaining a qualitative understanding of phonation. However, quantitative discrepancies remain large due to an inaccurate estimation of the model parameters and the crudeness in either flow or mechanical model description. As an illustration it is shown that significant improvements can be made by accounting for viscous flow effects.

  • 87.
    Saeidi, Davood
    et al.
    Isfahan Univ Technol, Dept Mech Engn, Esfahan, Iran..
    Saghafian, Mohsen
    Isfahan Univ Technol, Dept Mech Engn, Esfahan, Iran..
    Javanmard, Shaghayegh Haghjooy
    Isfahan Univ Med Sci, Dept Physiol, Cardiovasc Res Inst, Appl Physiol Res Ctr, Esfahan, Iran..
    Hammarström, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Wiklund, Martin
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Acoustic dipole and monopole effects in solid particle interaction dynamics during acoustophoresis2019Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 145, nr 6, s. 3311-3319Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A method is presented for measurements of secondary acoustic radiation forces acting on solid particles in a plain ultrasonic standing wave. The method allows for measurements of acoustic interaction forces between particles located in arbitrary positions such as in between a pressure node and a pressure antinode. By utilizing a model that considers both density- and compressibility-dependent effects, the observed particle-particle interaction dynamics can be well understood. Two differently sized polystyrene micro-particles (4.8 and 25 mu m, respectively) were used in order to achieve pronounced interaction effects. The particulate was subjected to a 2-MHz ultrasonic standing wave in a microfluidic channel, such as commonly used for acoustophoresis. Observation of deflections in the particle pathways shows that the particle interaction force is not negligible under this circumstance and has to be considered in accurate particle manipulation applications. The effect is primarily pronounced when the distance between two particles is small, the sizes of the particles are different, and the acoustic properties of the particles are different relative to the media. As predicted by theory, the authors also observe that the interaction forces are affected by the angle between the inter-particle centerline and the axis of the standing wave propagation direction.

  • 88.
    Salomão, Glaucia Lais
    et al.
    Applied Linguistic and Language Studies Program, Pontifical Catholic University, Perdizes, 05014-001 São Paulo, R. Monte Alegre, 984, Corredor Cardoso de Almeida, Brazil.
    Sundberg, Johan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Tal, musik och hörsel, TMH.
    Relation between perceived voice register and flow glottogram parameters in males2008Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 124, nr 1, s. 546-551Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The perception of modal and falsetto registers was analyzed in a material consisting of a total of 104 vowel sounds sung by 13 choir singers, 52 sung in modal register, and 52 in falsetto register. These vowel sounds were classified by 16 expert listeners in a forced choice test and the number of votes for modal was compared to the voice source parameters: (1) closed quotient (Q(closed)), (2) level difference between the two lowest source spectrum partials (H1-H2), (3) AC amplitude, (4) maximum flow declination rate (MFDR), and (5) normalized amplitude quotient (NAQ, AC amplitude/MFDR* fundamental frequency). Tones with a high value of Q(closed) and low values of H1-H2 and of NAQ were typically associated with high number of votes for modal register, and vice versa, Q(closed) showing the strongest correlation. Some singer subjects produced tones that could not be classified as either falsetto or modal register, suggesting that classification of registers is not always feasible.

  • 89. Scherer, K. R.
    et al.
    Sundberg, Johan
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH.
    Fantini, B.
    Trznadel, S.
    Eyben, F.
    The expression of emotion in the singing voice: Acoustic patterns in vocal performance2017Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 142, nr 4, s. 1805-1815Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There has been little research on the acoustic correlates of emotional expression in the singing voice. In this study, two pertinent questions are addressed: How does a singer's emotional interpretation of a musical piece affect acoustic parameters in the sung vocalizations? Are these patterns specific enough to allow statistical discrimination of the intended expressive targets? Eight professional opera singers were asked to sing the musical scale upwards and downwards (using meaningless content) to express different emotions, as if on stage. The studio recordings were acoustically analyzed with a standard set of parameters. The results show robust vocal signatures for the emotions studied. Overall, there is a major contrast between sadness and tenderness on the one hand, and anger, joy, and pride on the other. This is based on low vs high levels on the components of loudness, vocal dynamics, high perturbation variation, and a tendency for high low-frequency energy. This pattern can be explained by the high power and arousal characteristics of the emotions with high levels on these components. A multiple discriminant analysis yields classification accuracy greatly exceeding chance level, confirming the reliability of the acoustic patterns.

  • 90.
    Schickhofer, Lukas
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Biomekanik. KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik.
    Malinen, Jarmo
    Aalto University.
    Mihaescu, Mihai
    KTH, Skolan för industriell teknik och management (ITM), Centra, Competence Center for Gas Exchange (CCGEx). KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för teknikvetenskap (SCI), Mekanik, Processteknisk strömningsmekanik.
    Compressible flow simulations of phonation using realistic vocal tract geometries2019Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Voiced speech consists mainly of the source signal that is frequency-weighted by the acoustic filtering of the upper airways and vortex-induced sound through perturbation in the flow field. This study investigates the flow instabilities leading to vortex shedding and the importance of coherent structures in the supraglottal region downstream of the vocal folds for the far-field sound signal. Large eddy simulations of the compressible airflow through the glottal contriction are performed in realistic geometries obtained from three-dimensional magnetic resonance imaging data. Intermittent flow separation through the glottis is shown to introduce unsteady surface pressure through impingement of vortices. Additionally, dominant flow instabilities develop in the shear layer associated with the glottal jet. The aerodynamic perturbations in the near field and the acoustic signal in the far field is examined by means of spatial and temporal Fourier analysis. Furthermore, the acoustic sources due to the unsteady supraglottal flow are identified with the aid of surface spectra and critical regions of amplification of the dominant frequencies of the investigated vowel geometries are identified.

  • 91.
    Schickhofer, Lukas
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Mekanik, Strömningsfysik. KTH, Skolan för teknikvetenskap (SCI), Mekanik, Biomekanik.
    Malinen, Jarmo
    Aalto University.
    Mihaescu, Mihai
    KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Compressible flow simulations of voiced speech using rigid vocal tract geometries acquired by MRI2019Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 145, nr 4, s. 2049-2061, artikkel-id 0001-4966/2019/145(4)/2049/13Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Voiced speech consists mainly of the source signal that is frequency weighted by the acoustic filtering of the upper airways and vortex-induced sound through perturbation in the flow field. This study investigates the flow instabilities leading to vortex shedding and the importance of coherent structures in the supraglottal region downstream of the vocal folds for the far-field sound signal. Large eddy simulations of the compressible airflow through the glottal constriction are performed in realistic geometries obtained from three-dimensional magnetic resonance imaging data. Intermittent flow separation through the glottis is shown to introduce unsteady surface pressure through impingement of vortices. Additionally, dominant flow instabilities develop in the shear layer associated with the glottal jet. The aerodynamic perturbations in the near field and the acoustic signal in the far field are examined by means of spatial and temporal Fourier analysis. Furthermore, the acoustic sources due to the unsteady supraglottal flow are identified with the aid of surface spectra, and critical regions of amplification of the dominant frequencies of the investigated vowel geometries are identified.

    Fulltekst (pdf)
    fulltext
  • 92. Scholte, R.
    et al.
    Lopez Arteaga, Ines
    Eindhoven University of Technology.
    Bert Roozen, N.
    Nijmeijer, H.
    Truncated aperture extrapolation for Fourier-based near-field acoustic holography by means of border-padding2009Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 125, nr 6, s. 3844-3854Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Although near-field acoustic holography (NAH) is recognized as a powerful and extremely fast acoustic imaging method based on the inverse solution of the wave-equation, its practical implementation has suffered from problems with the use of the discrete Fourier transformation (DFT) in combination with small aperture sizes and windowing. In this paper, a method is presented that extrapolates the finite spatial aperture before the DFT is applied, which is based on the impulse response information of the known aperture data. The developed method called linear predictive border-padding is an aperture extrapolation technique that greatly reduces leakage and spatial truncation errors in planar NAH (PNAH). Numerical simulations and actual measurements on a hard-disk drive and a cooling fan illustrate the low error, high speed, and utilization of border-padding. Border-padding is an aperture extrapolation technique that makes PNAH a practical and accurate inverse near-field acoustic imaging method.

  • 93.
    Schoonderwaldt, Erwin
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH, Musikakustik.
    Demoucron, M.
    Rasamimanana, N.
    A setup for measurement of bowing parameters in bowed-string instrument performance (Abstract)2008Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 123, nr 5, s. 3664-Artikkel i tidsskrift (Fagfellevurdert)
  • 94.
    Schoonderwaldt, Erwin
    et al.
    KTH, Tidigare Institutioner (före 2005), Tal, musik och hörsel.
    Friberg, Anders
    KTH, Tidigare Institutioner (före 2005), Tal, musik och hörsel.
    Bresin, Roberto
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Intelligenta system, Tal, musik och hörsel, TMH.
    Juslin, P. N.
    Uppsala University.
    A system for improving the communication of emotion in music performance by feedback learning2002Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 111, nr 5, s. 2471-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Expressivity is one of the most important aspects of music performance. However, in music education, expressivity is often overlooked in favor of technical abilities. This could possibly depend on the difficulty in describing expressivity, which makes it problematic to provide the student with specific feedback. The aim of this project is to develop a computer program, which will improve the students’ ability in communicating emotion in music performance. The expressive intention of a performer can be coded in terms of performance parameters (cues), such as tempo, sound level, timbre, and articulation. Listeners’ judgments can be analyzed in the same terms. An algorithm was developed for automatic cue extraction from audio signals. Using note onset–offset detection, the algorithm yields values of sound level, articulation, IOI, and onset velocity for each note. In previous research, Juslin has developed a method for quantitative evaluation of performer–listener communication. This framework forms the basis of the present program. Multiple regression analysis on performances of the same musical fragment, played with different intentions, determines the relative importance of each cue and the consistency of cue utilization. Comparison with built‐in listener models, simulating perceived expression using a regression equation, provides detailed feedback regarding the performers’ cue utilization.

  • 95. Sciallero, Claudia
    et al.
    Grishenkov, Dmitry
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinsk avbildning.
    Kothapalli, Satya V. V. N.
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinsk avbildning.
    Oddo, Letizia
    Trucco, Andrea
    Acoustic characterization and contrast imaging of microbubbles encapsulated by polymeric shells coated or filled with magnetic nanoparticles2013Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 134, nr 5, s. 3918-3930Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The combination of superparamagnetic iron oxide nanoparticles with polymeric air-filled microbubbles is used to produce two types of multimodal contrast agents to enhance medical ultrasound and magnetic resonance imaging. The nanoparticles are either covalently linked to the shell or physically entrapped into the shell. In this paper, the characterization of the acoustic properties (backscattered power, fracturing pressure, attenuation and dispersion of the ultrasonic wave) and ultrasound imaging of the two types of magnetic microbubbles are presented. In vitro B-mode images are generated using a medical ultrasound scanner by applying a nonconventional signal processing technique that is suitable to detect polymeric bubbles and based on the combination of multipulse excitation and chirp coding. Even if both types of microbubbles can be considered to be effective ultrasound contrast agents, the different structure of the shell loaded with nanoparticles has a pronounced effect on the echogenicity and the detection sensitivity of the imaging technique. The best results are obtained using microbubbles that are externally coated with nanoparticles. A backscattered power of 20 dB was achieved at lower concentration, and an increment of 8 dB in the contrast-to-tissue ratio was observed with respect to the more rigid microbubbles with particles entrapped into the shell.

  • 96.
    Selamtzis, Andreas
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH.
    Ternström, Sten
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH, Musikakustik.
    Richter, Bernard
    Burk, Fabian
    Köberlein, Marie
    Echternach, Matthias
    A comparison of electroglottographic and glottal area waveforms for phonation type differentiation in male professional singers2018Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, ISSN 0001-4966, Vol. 144, nr 6, s. 3275-3288Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study compares the use of electroglottograms (EGGs) and glottal area waveforms (GAWs) to study phonation in different vibratory states as produced by professionally trained singers. Six western classical tenors were asked to phonate pitch glides from modal to falsetto phonation, or from modal to their stage voice above the passaggio (SVaP). For each pitch glide the sample entropy (SampEn) of the EGG signal was calculated to detect the occurrence of phonatory instabilities and establish a ᅵground truthᅵ for the performed phonation type. The cycles before the maximum SampEn were labeled as modal, and the cycles after the peak were labeled as either falsetto, or SVaP. Three automatic categorizations of vibratory state were performed using clustering: one based only on the EGG, one based on the GAW, and one based on their combination. The error rate (clustering vs ground truth) was, on average, lower than 10% for all of the three settings, revealing no special advantage of the GAW over EGG, and vice vers...

  • 97.
    Semeniuk, Bradley
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Numerisk akustik. Centre for ECO2 Vehicle Design.
    Microstructure based estimation of the dynamic drag impedance of lightweight fibrous materials2017Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 141, nr 3, s. 1360-1370Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper focusses on the prediction of one of the main mechanisms of acoustic attenuation, the dynamic drag impedance, of a bundle of fibres typical of lightweight fibrous porous materials. The methodology uses geometrical properties derived from microscopy, and is based on the assumption that the interaction between the shear stress fields of neighbouring fibres may be neglected in the predicted drag force of an individual fibre. An analytical procedure is discussed which provides an estimate of the drag forces acting on infinite longitudinal and transversely orientated cylinders oscillating sinusoidally in a viscous incompressible fluid of infinite extent, at rest. The frequency-dependent viscous drag forces are estimated from the shear stresses on the surface of the cylinders, and may be scaled in terms of fibre diameter distributions and orientation angles in order to predict the dynamic drag impedance of a real material. The range of validity for this modelling approach is assessed through finite element solutions of three different fibre arrangements.

    Fulltekst (pdf)
    fulltext
  • 98.
    Semeniuk, Bradley
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Teknisk mekanik.
    Lundberg, Eva
    KTH, Skolan för teknikvetenskap (SCI), Teknisk mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Göransson, Peter
    KTH, Skolan för teknikvetenskap (SCI), Teknisk mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Acoustics modelling of open-cell foam materials from microstructure and constitutive properties2021Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 149, nr 3, s. 2016-2026Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The dynamic relations for highly porous fibrous materials, having analytical expressions for dynamic viscous drag forces and oscillatory solid-to-fluid heat transfer, are now extended towards open-cell foam materials where the struts of the foam are considered to be primarily cylindrical except in the region of the joints. By also including analytical expressions for the stiffness of the foam cell, an entirely analytically-based model is presented for the acoustics of highly-porous, open-celled foam materials. This approach is extremely efficient, requiring only the mean cell size, mean strut diameter, and constitutive properties of the solid foam material and the surrounding viscous fluid as input. The acoustic performance prediction of not only isotropic foam cell designs, but also anisotropic ones may be performed rapidly and virtually, without the need for the determination of poroelastic material properties from existing material samples. The steps required for the development of the analytical foam-cell model are presented, along with the acoustic performance prediction of a typical Melamine foam cell, yielding very promising results in comparison against measurements. In order to understand the suitability of the cylindrical foam strut assumption, a viscous drag force comparison with foam struts having square and triangular cross-sectional profiles is also presented.

  • 99.
    Shaglwf, Zaid
    et al.
    Univ Southampton, Fac Engn & Phys Sci, Sch Engn, Southampton SO17 1BJ, Hants, England..
    Hammarström, Björn
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Biomedicinsk fysik och röntgenfysik.
    Laila, Dina Shona
    Coventry Univ, Sch Mech Aerosp & Automot, Coventry CV1 5FB, W Midlands, England..
    Hill, Martyn
    Univ Southampton, Fac Engn & Phys Sci, Sch Engn, Southampton SO17 1BJ, Hants, England..
    Glynne-Jones, Peter
    Univ Southampton, Fac Engn & Phys Sci, Sch Engn, Southampton SO17 1BJ, Hants, England..
    Acoustofluidic particle steering2019Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 145, nr 2, s. 945-955Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Steering micro-objects using acoustic radiation forces is challenging for several reasons: resonators tend to create fixed force distributions that depend primarily on device geometry, and even when using switching schemes, the forces are hard to predict a priori. In this paper an active approach is developed that measures forces from a range of acoustic resonances during manipulation using a computer controlled feedback loop based in MATLAB, with a microscope camera for particle imaging. The arrangement uses a planar resonator where the axial radiation force is used to hold particles within a levitation plane. Manipulation is achieved by summing the levitation frequency with an algorithmically chosen second resonance frequency, which creates lateral forces derived from gradients in the kinetic energy density of the acoustic field. Apart from identifying likely resonances, the system does not require a priori knowledge of the structure of the acoustic force field created by each resonance. Manipulation of 10 mu m microbeads is demonstrated over 100 s mu m. Manipulation times are of order 10 s for paths of 200 mu m length. The microfluidic device used in this work is a rectangular glass capillary with a 6 mm wide and 300 mu m high fluid chamber.

  • 100. Siciliano, C.
    et al.
    Williams, G.
    Faulkner, A.
    Salvi, Giampiero
    KTH, Tidigare Institutioner (före 2005), Tal, musik och hörsel.
    Intelligibility of an ASR-controlled synthetic talking face2004Inngår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 115, nr 5, s. 2428-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The goal of the SYNFACE project is to develop a multilingual synthetic talking face, driven by an automatic speech recognizer (ASR), to assist hearing‐impaired people with telephone communication. Previous multilingual experiments with the synthetic face have shown that time‐aligned synthesized visual face movements can enhance speech intelligibility in normal‐hearing and hearing‐impaired users [C. Siciliano et al., Proc. Int. Cong. Phon. Sci. (2003)]. Similar experiments are in progress to examine whether the synthetic face remains intelligible when driven by ASR output. The recognizer produces phonetic output in real time, in order to drive the synthetic face while maintaining normal dialogue turn‐taking. Acoustic modeling was performed with a neural network, while an HMM was used for decoding. The recognizer was trained on the SpeechDAT telephone speech corpus. Preliminary results suggest that the currently achieved recognition performance of around 60% frames correct limits the usefulness of the synthetic face movements. This is particularly true for consonants, where correct place of articulation is especially important for visual intelligibility. Errors in the alignment of phone boundaries representative of those arising in the ASR output were also shown to decrease audio‐visual intelligibility.

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