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  • 1. Cops, Mark J.
    et al.
    McDaniel, J. Gregory
    Magliula, Elizabeth A.
    Bamford, David J.
    Berggren, Martin
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Estimation of acoustic absorption in porous materials based on visco-thermal boundary layers modeled as boundary conditions2020In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 148, no 3, p. 1624-1635Article in journal (Refereed)
    Abstract [en]

    A method for estimating acoustic absorption in porous materials is presented in which the thermal and viscous boundary layers are modeled through boundary conditions to the Helmholtz equation for the acoustic pressure. The method is proposed for rigid-framed porous materials in which vibration of the frame is negligible compared to pressure fluctuations in air. The method reduces computation times by 2 orders of magnitude compared to a full thermoviscous acoustic solver. Furthermore, the method is shown to be highly accurate over geometrical features and frequencies of interest as long as thermal and viscous boundary layers do not overlap and the effects of the sharp changes in curvature are negligible. The method is demonstrated for a periodic sound absorber from the literature as well as a sound absorber with a randomly graded microstructure.

  • 2.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Holmberg, Jenny
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Södersten, Maria
    Division of Speech and Language Pathology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden; Medical Unit Allied Health Professionals, Section Speech and Language Pathology, Karolinska University Hospital, Stockholm, Sweden.
    Acoustic cues to femininity and masculinity in spontaneous speech2024In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 155, no 5, p. 3090-3100Article in journal (Refereed)
    Abstract [en]

    The perceived level of femininity and masculinity is a prominent property by which a speaker’s voice is indexed, and a vocal expression incongruent with the speaker’s gender identity can greatly contribute to gender dysphoria. Our understanding of the acoustic cues to the levels of masculinity and femininity perceived by listeners in voices is not well developed, and an increased understanding of them would benefit communication of therapy goals and evaluation in gender-affirming voice training. We developed a voice bank with 132 voices with a range of levels of femininity and masculinity expressed in the voice, as rated by 121 listeners in independent, individually randomized perceptual evaluations. Acoustic models were developed from measures identified as markers of femininity or masculinity in the literature using penalized regression and tenfold cross-validation procedures. The 223 most important acoustic cues explained 89% and 87% of the variance in the perceived level of femininity and masculinity in the evaluation set, respectively. The median fo was confirmed to provide the primary cue, but other acoustic properties must be considered in accurate models of femininity and masculinity perception. The developed models are proposed to afford communication and evaluation of gender-affirming voice training goals and improve voice synthesis efforts.

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  • 3.
    Karlsson, Fredrik
    et al.
    Umeå University, Faculty of Medicine, Department of Clinical Sciences, Speech and Language Therapy.
    Schalling, Ellika
    Laakso, Katja
    Johansson, Kerstin M.
    Hartelius, Lena
    Assessment of speech impairment in patients with Parkinson's disease from acoustic quantifications of oral diadochokinetic sequences2020In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 147, no 2, p. 839-851Article in journal (Refereed)
    Abstract [en]

    This investigation aimed at determining whether an acoustic quantification of the oral diadochokinetic (DDK)task may be used to predict the perceived level of speech impairment when speakers with Parkinson's disease(PD) are reading a standard passage. DDK sequences with repeated [pa], [ta], and [ka] syllables were collectedfrom 108 recordings (68 unique speakers with PD), along with recordings of the speakers reading a standardizedtext. The passage readings were assessed in five dimensions individually by four speech-language pathologists ina blinded and randomized procedure. The 46 acoustic DDK measures were merged with the perceptual ratings ofread speech in the same recording session. Ordinal regression models were trained repeatedly on 80% of ratingsand acoustic DDK predictors per dimension in 10-folds, and evaluated in testing data. The models developedfrom [ka] sequences achieved the best performance overall in predicting the clinicians' ratings of passage readings. The developed [pa] and [ta] models showed a much lower performance across all dimensions. The additionof samples with severe impairments and further automation of the procedure is required for the models to be usedfor screening purposes by non-expert clinical staff.

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  • 4.
    Madison, Guy
    et al.
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Paulin, Johan
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    Ratings of speed in real music as a function of both original and manipulated tempo2010In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 128, no 5, p. 3032-3040Article in journal (Refereed)
    Abstract [en]

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

  • 5.
    Mousavi, Abbas
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Berggren, Martin
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Hägg, Linus
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Wadbro, Eddie
    Umeå University, Faculty of Science and Technology, Department of Computing Science. Department of Mathematics and Computer Science, Karlstad University, Karlstad, Sweden.
    Topology optimization of a waveguide acoustic black hole for enhanced wave focusing2024In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 155, no 1, p. 742-756Article in journal (Refereed)
    Abstract [en]

    The waveguide acoustic black hole (WAB) effect is a promising approach for controlling wave propagation in various applications, especially for attenuating sound waves. While the wave-focusing effect of structural acoustic black holes has found widespread applications, the classical ribbed design of waveguide acoustic black holes (WABs) acts more as a resonance absorber than a true wave-focusing device. In this study, we employ a computational design optimization approach to achieve a conceptual design of a WAB with enhanced wave-focusing properties. We investigate the influence of viscothermal boundary losses on the optimization process by formulating two distinct cases: one neglecting viscothermal losses and the other incorporating these losses using a recently developed material distribution topology optimization technique. We compare the performance of optimized designs in these two cases with that of the classical ribbed design. Simulations using linearized compressible Navier–Stokes equations are conducted to evaluate the wave-focusing performance of these different designs. The results reveal that considering viscothermal losses in the design optimization process leads to superior wave-focusing capabilities, highlighting the significance of incorporating these losses in the design approach. This study contributes to the advancement of WAB design and opens up new possibilities for its applications in various fields.

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  • 6.
    Mousavi, Abbas
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Berggren, Martin
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Wadbro, Eddie
    Department of Mathematics and Computer Science, Karlstad University, Karlstad, Sweden.
    How the waveguide acoustic black hole works: A study of possible damping mechanisms2022In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 151, no 6, p. 4279-4290Article in journal (Refereed)
    Abstract [en]

    The acoustic black hole (ABH) effect in waveguides is studied using frequency-domain finite element simulations of a cylindrical waveguide with an embedded ABH termination composed of retarding rings. This design is adopted from an experimental study in the literature, which surprisingly showed, contrary to the structural counterpart, that the addition of damping material to the end of the waveguide does not significantly reduce the reflection coefficient any further. To investigate this unexpected behavior, we model different damping mechanisms involved in the attenuation of sound waves in this setup. A sequence of computed pressure distributions indicates occurrences of frequency-dependent resonances in the device. The axial position of the cavity where the resonance occurs can be predicted by a more elaborate wall admittance model than the one that was initially used to study and design ABHs. The results of our simulations show that at higher frequencies, the visco-thermal losses and the damping material added to the end of the setup do not contribute significantly to the performance of the device. Our results suggest that the primary source of damping, responsible for the low reflection coefficients at higher frequencies, is local absorption effects at the outer surface of the cylinder.

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  • 7.
    Mousavi, Abbas
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Berggren, Martin
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Wadbro, Eddie
    Department of Mathematics and Computer Science, Karlstad University, Karlstad, Sweden.
    On the acoustic black-hole effect in waveguides2021In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 149, no 4, article id A108Article in journal (Refereed)
    Abstract [en]

    The acoustic black-hole (ABH) effect is a well-known way of controlling structural vibrations in solid beams and plates. The theory behind this effect is to reduce the velocity of waves by altering the physical properties of the domain according to a power-law profile. For an ideal ABH, this leads to vanishing reflections from the end of the termination. In practice, there will be a truncation in the profile, which leads to some reflections. A well-known way of minimizing this truncation error is to add damping material to the end of the ABH termination.

    For a waveguide embedding a set of rings with retarding inner radius according to a power-law profile, the velocity of sound waves tends to zero. However, unlike the structural counterpart, experimental results in the literature show that adding damping material to reduce the truncation error is not effective for waveguides. Here, we present a finite element simulation of the considered cylindrical setup. Our results confirm that the addition of damping material to the end of the waveguide is ineffective while suggesting that the local absorption effects at the lateral surface of the cylinder are a primary source of damping to achieve the ABH effect.

  • 8.
    Noreland, Daniel
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Udawalpola, Rajitha
    Department of Information Technology, Uppsala University.
    Berggren, Martin
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    A hybrid scheme for bore design optimization of a brass instrument2010In: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 128, no 3, p. 1391-1400Article in journal (Refereed)
    Abstract [en]

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

1 - 8 of 8
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  • ieee
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  • vancouver
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  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
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  • text
  • asciidoc
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