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  • 51.
    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 recognition2010Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 127, nr 2, s. EL73-EL79Artikel i tidskrift (Refereegranskat)
    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.

  • 52. 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 piano2009Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 126, nr 2, s. EL49-EL54Artikel i tidskrift (Refereegranskat)
    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.

  • 53.
    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 layers2013Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 133, nr 5, s. EL426-EL430Artikel i tidskrift (Refereegranskat)
    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.

  • 54.
    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 core2014Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 135, nr 5, s. 2683-2693Artikel i tidskrift (Refereegranskat)
    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.

  • 55. 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 aids2010Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 127, nr 3, s. 1491-1505Artikel i tidskrift (Refereegranskat)
    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]

  • 56.
    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 test2010Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 127, nr 5, s. 3223-3231Artikel i tidskrift (Refereegranskat)
    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.

  • 57. 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 filtering2012Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 131, nr 1, s. 435-441Artikel i tidskrift (Refereegranskat)
    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.

  • 58.
    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 structures2010Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 127, nr 1, s. 435-444Artikel i tidskrift (Refereegranskat)
  • 59.
    Nilsson, A. C.
    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 cores2018Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 144, nr 3, s. 1600-1614Artikel i tidskrift (Refereegranskat)
    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.

  • 60.
    Nordqvist, Peter
    et al.
    KTH, Tidigare Institutioner, Tal, musik och hörsel.
    Leijon, Arne
    KTH, Tidigare Institutioner, Tal, musik och hörsel.
    An efficient robust sound classification algorithm for hearing aids2004Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 115, nr 6, s. 3033-3041Artikel i tidskrift (Refereegranskat)
    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.

  • 61.
    Nordqvist, Peter
    et al.
    KTH, Tidigare Institutioner, Tal, musik och hörsel.
    Leijon, Arne
    KTH, Tidigare Institutioner, Tal, musik och hörsel.
    Hearing-aid automatic gain control adapting to two sound sources in the environment, using three time constants2004Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 116, nr 5, s. 3152-3155Artikel i tidskrift (Refereegranskat)
    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.

  • 62.
    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 media2016Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 140, nr 2, s. EL218-EL220Artikel i tidskrift (Refereegranskat)
    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.

  • 63.
    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 framework2004Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 116, nr 4, s. 1938-1947Artikel i tidskrift (Refereegranskat)
    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.

  • 64.
    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 analysis2007Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 122, nr 4, s. 2425-2430Artikel i tidskrift (Refereegranskat)
    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.

  • 65.
    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 crack2005Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 117, nr 2, s. 592-600Artikel i tidskrift (Refereegranskat)
    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.

  • 66.
    Peplow, Andrew
    et al.
    KTH, Tidigare Institutioner, Farkostteknik.
    Finnveden, Svante
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Strukturakustik.
    A super-spectral finite element method for sound transmission in waveguides2004Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 116, nr 3, s. 1389-1400Artikel i tidskrift (Refereegranskat)
    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.

  • 67. Pobloth, H.
    et al.
    Kleijn, W. Bastiaan
    KTH, Tidigare Institutioner                               , Signaler, sensorer och system.
    Squared error as a measure of perceived phase distortion2003Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 114, nr 2, s. 1081-1094Artikel i tidskrift (Refereegranskat)
    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.

  • 68.
    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 efficiency2012Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 132, artikel-id 1928Artikel i tidskrift (Refereegranskat)
    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

  • 69. 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 morphology2009Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 125, nr 1, s. 503-512Artikel i tidskrift (Refereegranskat)
    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.

  • 70. Rossing, T D
    et al.
    Sundberg, Johan
    KTH, Skolan för elektroteknik och datavetenskap (EECS), 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.1987Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 82, nr 3, s. 830-836Artikel i tidskrift (Refereegranskat)
    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.

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

  • 72.
    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 models2012Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 132, nr 5, s. 3162-3179Artikel i tidskrift (Refereegranskat)
    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.

  • 73.
    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 problems2013Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 133, nr 5, s. 3241-3241Artikel i tidskrift (Refereegranskat)
    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.

  • 74.
    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 problems2017Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 141, nr 5, s. 4033-4033Artikel i tidskrift (Refereegranskat)
    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.

  • 75.
    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 applications2013Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 134, nr 6, s. 4730-4741Artikel i tidskrift (Refereegranskat)
    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.

  • 76. 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 models2007Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 121, nr 1, s. 479-490Artikel i tidskrift (Refereegranskat)
    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.

  • 77.
    Salomão, Glaucia Lais
    et al.
    Pontifical Catholic University, Sao Paolo, Brazil.
    Sundberg, Johan
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH, Musikakustik.
    Relation between perceived voice register and flow glottogram parameters in males2008Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 124, nr 1, s. 546-551Artikel i tidskrift (Refereegranskat)
    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.

  • 78. 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 performance2017Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 142, nr 4, s. 1805-1815Artikel i tidskrift (Refereegranskat)
    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.

  • 79.
    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 geometries2019Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524Artikel i tidskrift (Refereegranskat)
    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.

  • 80.
    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 MRI2019Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 145, nr 4, s. 2049-2061, artikel-id 0001-4966/2019/145(4)/2049/13Artikel i tidskrift (Refereegranskat)
    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.

  • 81. 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-padding2009Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 125, nr 6, s. 3844-3854Artikel i tidskrift (Refereegranskat)
    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.

  • 82.
    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)2008Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 123, nr 5, s. 3664-Artikel i tidskrift (Refereegranskat)
  • 83.
    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), Tal, musik och hörsel, TMH.
    Juslin, P. N.
    Uppsala University.
    A system for improving the communication of emotion in music performance by feedback learning2002Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 111, nr 5, s. 2471-Artikel i tidskrift (Refereegranskat)
    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.

  • 84. 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 nanoparticles2013Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 134, nr 5, s. 3918-3930Artikel i tidskrift (Refereegranskat)
    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.

  • 85.
    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 singers2018Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, ISSN 0001-4966, Vol. 144, nr 6, s. 3275-3288Artikel i tidskrift (Refereegranskat)
    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...

  • 86.
    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 materials2017Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 141, nr 3, s. 1360-1370Artikel i tidskrift (Refereegranskat)
    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.

  • 87.
    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 steering2019Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 145, nr 2, s. 945-955Artikel i tidskrift (Refereegranskat)
    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.

  • 88. Siciliano, C.
    et al.
    Williams, G.
    Faulkner, A.
    Salvi, Giampiero
    KTH, Tidigare Institutioner, Tal, musik och hörsel.
    Intelligibility of an ASR-controlled synthetic talking face2004Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 115, nr 5, s. 2428-Artikel i tidskrift (Refereegranskat)
    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.

  • 89.
    Sjölander, Peta
    et al.
    KTH, Tidigare Institutioner (före 2005), Tal, musik och hörsel.
    Sundberg, Johan
    KTH, Tidigare Institutioner (före 2005), Tal, musik och hörsel.
    Spectrum effects of subglottal pressure variation in professional baritone singers2004Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 115, nr 3, s. 1270-1273Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The audio signal from five professional baritones was analyzed by means of spectrum analysis. Each subject sang syllables [pae] and [pa] from loudest to softest phonation at fundamental frequencies representing 25%, 50%, and 75% of his total range. Ten subglottal pressures, equidistantly spaced between highest and lowest, were selected for analysis along with the corresponding production of the vowels. The levels of the first formant and singer's formant were measured as a function of subglottal pressure. Averaged across subjects, vowels, and F-0, a 10-dB increase at 600 Hz was accompanied by a 16-dB increase at 3 kHz.

  • 90.
    Smeds, Karolina
    et al.
    ORCA-Europe/Widex.
    Leijon, Arne
    KTH, Skolan för elektro- och systemteknik (EES), Kommunikationsteori. ORCA-Europe/Widex.
    Wolters, Florian
    ORCA-Europe/Widex.
    Hammarstedt, Anders
    ORCA-Europe/Widex.
    Båsjö, Sara
    ORCA-Europe/Widex.
    Hertzman, Sofia
    ORCA-Europe/Widex.
    Comparison of predictive measures of speech recognition after noise reduction processing2014Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 136, nr 3, s. 1363-1374Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A number of measures were evaluated with regard to their ability to predict the speech-recognition benefit of single-channel noise reduction (NR) processing. Three NR algorithms and a reference condition were used in the evaluation. Twenty listeners with impaired hearing and ten listeners with normal hearing participated in a blinded laboratory study. An adaptive speech test was used. The speech test produces results in terms of signal-to-noise ratios that correspond to equal speech recognition performance (in this case 80% correct) with and without the NR algorithms. This facilitates a direct comparison between predicted and experimentally measured effects of noise reduction algorithms on speech recognition. The experimental results were used to evaluate nine different predictive measures, one in two variants. The best predictions were found with the Coherence Speech Intelligibility Index (CSII) [Kates and Arehart (2005), J. Acoust. Soc. Am. 117(4), 2224-2237]. In general, measures using correlation between the clean speech and the processed noisy speech, as well as other measures that are based on short-time analysis of speech and noise, seemed most promising.

  • 91. Sramkova, Hana
    et al.
    Granqvist, Svante
    KTH, Skolan för teknik och hälsa (STH), Naturvetenskap och biomedicin, Grundläggande naturvetenskap. Karolinska Inst, Sweden.
    Herbst, Christian T.
    Svec, Jan G.
    The softest sound levels of the human voice in normal subjects2015Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 137, nr 1, s. 407-418Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Accurate measurement of the softest sound levels of phonation presents technical and methodological challenges. This study aimed at (1) reliably obtaining normative data on sustained softest sound levels for the vowel [a:] at comfortable pitch; (2) comparing the results for different frequency and time weighting methods; and (3) refining the Union of European Phoniatricians' recommendation on allowed background noise levels for scientific and equipment manufacturers' purposes. Eighty healthy untrained participants (40 females, 40 males) were investigated in quiet rooms using a head-mounted microphone and a sound level meter at 30 cm distance. The one-second-equivalent sound levels were more stable and more representative for evaluating the softest sustained phonations than the fast-time-weighted levels. At 30 cm, these levels were in the range of 48-61 dB(C)/41-53 dB(A) for females and 49-64 dB(C)/35-53 dB(A) for males (5% to 95% quantile range). These ranges may serve as reference data in evaluating vocal normality. In order to reach a signal-to-noise ratio of at least 10 dB for more than 95% of the normal population, the background noise should be below 25 dB(A) and 38 dB(C), respectively, for the softest phonation measurements at 30 cm distance. For the A-weighting, this is 15 dB lower than the previously recommended value.

  • 92.
    Strömbergsson, Sofia
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH. Karolinska Institutet (KI), Huddinge.
    Salvi, Giampiero
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH.
    House, David
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH.
    Acoustic and perceptual evaluation of category goodness of /t/ and /k/ in typical and misarticulated children's speech2015Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 137, nr 6, s. 3422-3435Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This investigation explores perceptual and acoustic characteristics of children's successful and unsuccessful productions of /t/ and /k/, with a specific aim of exploring perceptual sensitivity to phonetic detail, and the extent to which this sensitivity is reflected in the acoustic domain. Recordings were collected from 4- to 8-year-old children with a speech sound disorder (SSD) who misarticulated one of the target plosives, and compared to productions recorded from peers with typical speech development (TD). Perceptual responses were registered with regards to a visual-analog scale, ranging from "clear [t]" to "clear [k]." Statistical models of prototypical productions were built, based on spectral moments and discrete cosine transform features, and used in the scoring of SSD productions. In the perceptual evaluation, " clear substitutions" were rated as less prototypical than correct productions. Moreover, target-appropriate productions of /t/ and /k/ produced by children with SSD were rated as less prototypical than those produced by TD peers. The acoustical modeling could to a large extent discriminate between the gross categories /t/ and /k/, and scored the SSD utterances on a continuous scale that was largely consistent with the category of production. However, none of the methods exhibited the same sensitivity to phonetic detail as the human listeners.

  • 93. Sun, F.
    et al.
    Li, S.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Translational illusion of acoustic sources by transformation acoustics2017Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 142, nr 3, s. 1213-1218Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An acoustic illusion of creating a translated acoustic source is designed by utilizing transformation acoustics. An acoustic source shifter (ASS) composed of layered acoustic metamaterials is designed to achieve such an illusion. A practical example where the ASS is made with naturally available materials is also given. Numerical simulations verify the performance of the proposed device. The designed ASS may have some applications in, e.g., anti-sonar detection. © 2017 Acoustical Society of America.

  • 94.
    Sundberg, Johan
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH.
    Fahlstedt, Ellinor
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH.
    Morell, A.
    Effects on the glottal voice source of vocal loudness variation in untrained female and male voices2005Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 117, nr 2, s. 879-885Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Subglottal pressure is one of the main voice control factors, controlling vocal loudness. In this investigation the effects of subglottal pressure variation on the voice source in untrained female and male voices phonating at a low, a middle, and a high fundamental frequency are analyzed. The subjects produced a series of /pae/ syllables at varied degrees of vocal loudness, attempting to keep pitch constant. Subglottal pressure was estimated from the oral pressure during the /p/ occlusion. Ten subglottal pressure values, approximately equidistantly spaced within the pressure range used, were identified, and the voice source of the vowels following these pressure values was analyzed by inverse filtering the airflow signal as captured by a Rothenberg mask. The maximum flow declination rate (MFDR) was found to increase linearly with subglottal pressure, but a given subglottal pressure produced lower values for female than for male voices. The closed quotient increased quickly with subglottal pressure at low pressures and slowly at high pressures, such that the relationship can be approximated by a power function. For a given subglottal pressure value, female voices reached lower values of closed quotient than male voices.

  • 95.
    Sundberg, Johan
    et al.
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH.
    Nordenberg, Maria
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH.
    Effects of vocal loudness variation on spectrum balance as reflected by the alpha measure of long-term-average spectra of speech2006Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 120, nr 1, s. 453-457Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The overall slope of long-term-average spectrum (LTAS) decreases if vocal loudness increases. Therefore, changes of vocal loudness also affects the a measure, defined as the ratio of spectrum intensity above and below 1000 Hz. The effect on a of loudness variation was analyzed in 15 male and 16 female voices reading a text at different degrees of vocal loudness. The mean range of equivalent sound level (Le) amounted to about 28 dB and the mean range of a to 19.0 and 11.7 dB for the female and male subjects. The L-eq vs. alpha relationship could be approximated with a quadratic function, or by a linear equation, if softest phonation was excluded. Using such equations a was computed for all values of L-eq observed for each subject and compared with observed values. The maximum and the mean absolute errors were 2.4 dB and between 0.1 and 0.6 dB. When softest phonation was disregarded and linear equations were used, the maximum error was less than 2 dB and the mean absolute errors were between 0.2 and 0.7 dB. The strong correlation between L-eq and a indicates that for a voice L-eq can be used for predicting alpha.

  • 96. Svec, Jan G.
    et al.
    Sundberg, Johan
    KTH, Skolan för datavetenskap och kommunikation (CSC), Tal, musik och hörsel, TMH.
    Hertegård, Stellan
    Three registers in an untrained female singer analyzed by videokymography, strobolaryngoscopy and sound spectrography2008Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 123, nr 1, s. 347-353Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There has been a lack of objective data on the singing voice registers, particularly on the so called "whistle" register, occurring in the top part of the female pitch range, which is accessible only to some singers. This study offers unique strobolaryngoscopic and high-speed (7812.5 images/s) videokymographic data on the vocal fold behavior of an untrained female singer capable of producing three distinct voice qualities, i.e., the chest, head and whistle registers. The sound was documented spectrographically. The transition from chest to head register, accompanied by pitch jumps, occurred around tones 134-C#5 (500-550 Hz) and was found to be associated with a slight decrease in arytenoids adduction, resulting in decrease of the closed quotient. The register shifts from head to whistle, also accompanied by pitch jumps, occurred around tones E5-B5 (670-1000 Hz) without any noticeable changes in arytenoids adduction. Some evidence was found for the vocal. tract influence on this transition. The mechanism of the vocal fold vibration in whistle register was found principally similar to that at lower registers: vibrations along the whole glottal length and vertical phase differences (indicated by sharp lateral peaks in videokymography) were seen on the vocal folds up to the highest tone G6 (1590 Hz).

  • 97. Tamadapu, Ganesh
    et al.
    Grishenkov, Dmitry
    KTH, Skolan för teknik och hälsa (STH), Medicinsk teknik, Medicinsk bildteknik.
    Eriksson, Anders
    Modeling and parametric investigation of thick encapsulated microbubble's nonspherical oscillations2016Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 140, nr 5, s. 3884-3895Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Numerous studies have been carried out in the past few decades to investigate the radial oscillations of encapsulated microbubbles (MBs). Nonspherical oscillations also have gained attention, being unavoidable in actual applications of these bubbles. The present paper is intended to describe the nature of resonance trends of such spherical and nonspherical modes of a thick encapsulated MB filled with air and suspended in water. The shell material is assumed to be linear viscoelastic and quasi-incompressible. The considered isotropic and spherically isotropic material parametric range is limited to thick polymer shelled MBs. For the case of an isotropic material, shell viscosity has a major influence on the fundamental modes with meridional wave number n = 0, 4, especially for thicker bubbles, unlike for the case of the spherically isotropic material case considered, where the viscosity has very little influence. For most of the parametric range, n = 2, 3 modes are underdamped and their frequency is found to be lower than the n = 0, 4 modes, for both material cases. An interesting case is found for a spherically isotropic quasiincompressible material case, where the first few nonspherical mode resonances are very close to radial mode resonance frequency.

  • 98.
    Temiz, Muttalip Askin
    et al.
    Eindhoven University of Technology, Department of Mechanical Engineering, Dynamics and Control, The Netherlands.
    Arteaga, Ines Lopez
    Eindhoven University of Technology, Department of Mechanical Engineering, Dynamics and Control, The Netherlands.
    Efraimsson, Gunilla
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg. KTH, Skolan för teknikvetenskap (SCI), Centra, VinnExcellence Center for ECO2 Vehicle design.
    Åbom, Mats
    KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, MWL Marcus Wallenberg Laboratoriet.
    Hirschberg, Avraham
    Eindhoven University of Technology, Department of Applied Physics, Gas Dynamics and Aero-Acoustics, The Netherlands.
    The influence of edge geometry on end-correction coefficients in micro perforated plates2015Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 138, nr 6, s. 3668-3677Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Global expressions are proposed for end-correction coefficients in micro perforated plates (MPPs) using non-dimensional parameters. MPPs are sound absorbers with small perforation diameters such that the Stokes boundary layers fill up almost the entire perforation. Sound absorption does not only occur within the perforation, but also takes place just outside of it. The latter contribution plus the outside inertia effect on the transfer impedance of the MPP are referred to as end-corrections. In order to determine them, an analytical solution employing the very thin Stokes layer assumption has been derived. However, this assumption requires empirical coefficients in the end-corrections for accurate results. To explore the effects of various parameters a numerical model is used. This model is verified with open-end reflection coefficient measurements. The most prominent result from this study is that compared to plate thickness, the ratio of perforation diameter to Stokes layer thickness (Shear number) and edge geometry affect the end-correction coefficients more significantly. The effect of plate thickness can be neglected for practical purposes, therefore, expressions for the end-corrections in terms of Shear number and edge geometry are provided. The relative error of these expressions is <3% compared to the numerical results. 

  • 99.
    Ternström, Sten
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Tal, musik och hörsel, TMH.
    Normalized time-domain parameters for electroglottographic waveforms2019Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 146, nr 1, s. EL65-EL70, artikel-id 1.5117174Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The electroglottographic waveform is of interest for characterizing phonation non-invasively. Existing parameterizations tend to give disparate results because they rely on somewhat arbitrary thresholds and/or contacting events. It is shown that neither are needed for formulating a normalized contact quotient and a normalized peak derivative. A heuristic combination of the two resolves also the ambiguity of a moderate contact quotient, with regard to vocal fold contacting being firm versus weak or absent. As preliminaries, schemes for electroglottography signal preconditioning and time-domain period detection are described that improve somewhat on similar methods. The algorithms are simple and compute quickly.

  • 100.
    Ternström, Sten
    KTH, Tidigare Institutioner, Tal, musik och hörsel.
    Preferred self-to-other ratios in choir singing1999Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 105, nr 6, s. 3563-3574Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Choir singers need to hear their own voice in an adequate self-to-other ratio (SOR) over the rest ofthe choir. Knowing singers’ preferences for SOR could facilitate the design of stages and of choral formations. In an experiment to study the preferred SOR, subjects sang sustained vowels together with synthesized choir sounds, whose loudness tracked that of their own voice. They could control the SOR simply by changing their distance to the microphone. At the most comfortable location, the SOR was measured. Experimental factors included unison and four-part tasks, three vowels and two levels of phonation frequency. The same experiment was run four times, using sopranos, altos, tenors, and basses, with stimulus tones adapted for each category. The preferred self-to-other ratios were found to be similar to SORs measured previously in actual performance, if a little higher. Preferences were quite narrow, typically +/-2 dB for each singer, but very different from singer to singer, with intrasubject means ranging from -1 to +15 dB. There was no significant difference between the unison and the four-part tasks, although this might have been caused by systematic differences in the stimulus sounds. Some effects of phonation frequency and vowel were significant, but interdependent and difficult to interpret. The results and their relevance to live choir singing are discussed.

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