| 1. |
- Askenfelt, Anders, et al.
(författare)
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Study of the spectral inharmonicity of musical sound by the algorithms of pitch extraction
- 2000
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Ingår i: Acoustical Physics. - : Pleiades Publishing Ltd. - 1063-7710 .- 1562-6865. ; 46:2, s. 121-132
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Tidskriftsartikel (refereegranskat)abstract
- The algorithms of pitch extraction are widely used in the studies of signals and, specifically, speech signals for the determination of the fundamental frequency. From the previous studies performed by Galembo and the calculations and experiments described in this paper, it follows that these methods can be adapted for the analysis and evaluation of the factors which form the sound property called pitch strength, pitch salience, or intonation clarity. Although this property plays an important role in music, it is quite poorly investigated. One of the aforementioned factors is represented by the distributed spectral inharmonicity which is typical of sounds produced, e.g., by strings. This paper presents a method of visualization, evaluation, and measurement of the inharmonicity of the spectrum of a musical sound with the help of the well-known algorithms of pitch extraction, namely the cepstrum and the harmonic product spectrum.
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| 2. |
- Broman, Göran, et al.
(författare)
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Instability of water jet : Aerodynamically induced acoustic and capillary waves
- 2012
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Ingår i: Acoustical Physics. - : MAIK NAUKA/INTERPERIODICA/SPRINGER. - 1063-7710 .- 1562-6865. ; 58:5, s. 537-541
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Tidskriftsartikel (refereegranskat)abstract
- High-speed water jet cutting has important industrial applications. To further improve the cutting performance it is critical to understand the theory behind the onset of instability of the jet. In this paper, instability of a water jet flowing out from a nozzle into ambient air is studied. Capillary forces and compressibility of the liquid caused by gas bubbles are taken into account, since these factors have shown to be important in previous experimental studies. A new dispersion equation, generalizing the analogous Rayleigh equation, is derived. It is shown how instability develops because of aerodynamic forces that appear at the streamlining of an initial irregularity of the equilibrium shape of the cross-section of the jet and how instability increases with increased concentration of gas bubbles. It is also shown how resonance phenomena are responsible for strong instability. On the basis of the theoretical explanations given, conditions for stable operation are indicated.
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| 3. |
- Dvoesherstov, M.Yu., et al.
(författare)
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Numerical and experimental analysis of the parameters of an electroacoustic thin-film microwave resonator
- 2013
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Ingår i: Acoustical Physics. - : Pleiades Publishing, Ltd.. - 1063-7710 .- 1562-6865. ; 59:5, s. 513-520
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Tidskriftsartikel (refereegranskat)abstract
- The results of numerical and experimental analysis of the parameters of a singlefrequency micro wave thinfilm electroacoustic resonator based on an (0001)AlN piezofilm with an acoustic reflector operat ing at a frequency of 10 GHz are presented. The effect of the reflector design on the resonator characteristics is considered. Using the modified Butterworth–Van Dyke model, it was shown that the ohmic resistance of electrodes and entrance paths substantially decreases the Qfactor at the resonance frequency of series and the acoustic losses in the resonator deteriorate the Qfactor at the parallel resonance frequency
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| 4. |
- Galembo, A. S., et al.
(författare)
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Overlapping of sounds in piano passages
- 2006
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Ingår i: Acoustical Physics. - : Pleiades Publishing Ltd. - 1063-7710 .- 1562-6865. ; 52:2, s. 144-150
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Tidskriftsartikel (refereegranskat)abstract
- It is well known that, in piano passages, specifically, in those played legato, sounds may overlap in time. Our experiments show that this overlapping is much greater than one would expect proceeding from the undistorted pitch perception in a given phrase. Moreover, the sounds produced by piano and perceived by a listener as clearly distinguished in pitch, when subjected to an objective analysis, may prove to be a mixture of equally intense components of the preceding and next sounds. This phenomenon is related to the problem of piano quality, including the still unclarified role of the damper system, as well as to the mysterious manifestation of pianist's personality that is called the art of touch.
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| 5. |
- Gray, Amber, et al.
(författare)
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An Intense Wave in Defective Media Containing Both Quadratic and Modular Nonlinearities : Shock Waves, Harmonics, and Nondestructive Testing
- 2018
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Ingår i: Acoustical Physics. - : Pleiades Publishing. - 1063-7710 .- 1562-6865. ; 64:4, s. 402-407
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Tidskriftsartikel (refereegranskat)abstract
- The observed nonclassical power-law dependence of the amplitude of the second harmonic wave on the amplitude of a harmonic pump wave is explained as a phenomenon associated with two types of nonlinearity in a structurally inhomogeneous medium. An approach to solving the inverse problem of determining the nonlinearity parameters and the exponent in the above-mentioned dependence is demonstrated. To describe the effects of strongly pronounced nonlinearity, equations containing a double nonlinearity and generalizing the Hopf and Burgers equations are proposed. The possibility of their exact linearization is demonstrated. The profiles, spectral composition, and average wave intensity in such doubly nonlinear media are calculated. The shape of the shock front is found, and its width is estimated. The wave energy losses that depend on both nonlinearity parameters—quadratic and modular—are calculated. © 2018, Pleiades Publishing, Ltd.
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| 6. |
- Gurbatov, S. N., et al.
(författare)
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Behavior of intense acoustic noise at large distances
- 2007
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Ingår i: Acoustical Physics. - 1063-7710 .- 1562-6865. ; 53:1, s. 48-63
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Tidskriftsartikel (refereegranskat)abstract
- Propagation of intense acoustic noise waves is investigated in the case of a nonplanar geometry. It is shown that, at large distances from the source, where the nonlinear effects become negligible, the spectrum of such waves has a universal self-similar shape. The amplitude of the spectrum is determined by a single constant D-infinity= D-infinity(epsilon, R-0) (the spectrum steepness at zero-valued argument) whose value depends on two dimensionless parameters: the inverse acoustic Reynolds number epsilon and the dimensionless radius R-0. It is shown that the plane of dimensionless parameters (epsilon, R-0) can be divided into four regions, so that, within each of them, the quantity D-infinity is described by a universal function of these parameters. The numerical factors of these parameters are found from numerical simulations.
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| 7. |
- Gurbatov, S. N., et al.
(författare)
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Transformation of High-Frequency Noise in the Field of a Shockwave
- 2018
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Ingår i: Acoustical Physics. - : PLEIADES PUBLISHING INC. - 1063-7710 .- 1562-6865. ; 64:5, s. 555-562
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Tidskriftsartikel (refereegranskat)abstract
- We study the interaction of noise and regular signals with a front whose steepness increases or decreases owing to nonlinear distortion of the profile of an intense pumping wave. Projective transformation is used, which is a result of one of the Burgers equation symmetries. Signal interaction with the pumping wave at its leading edge results in an increase in signal amplitude, a decrease in its time scale, an increase in the signal evolution rate, and earlier merging of discontinuities. At the trailing edge, an increase in signal amplitude, an increase in the time scale, and deceleration of the evolution rate occur. Formulas are obtained that describe the transformation of the spectrum and the correlation function of noise. Laws of the change in noise energy for both small and large Reynolds numbers are found. We study the interaction of weak noise with a nonstationary shock front in a medium with a finite viscosity. It is shown that, owing to competition between amplification at the shock front and high-frequency attenuation, the dependence on the noise intensity on distance has a nonmonotonic character, and at large distances, the intensity tends to zero, while the correlation time tends to a finite value.
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| 8. |
- Gusev, V.A., et al.
(författare)
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Intensification of the impact of high-intensity focused ultrasound (HIFU) with special spatiotemporal modulation
- 2013
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Ingår i: Acoustical Physics. - : Springer. - 1063-7710 .- 1562-6865. ; 59:1, s. 45-50
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Tidskriftsartikel (refereegranskat)abstract
- The principle of forming a special form of powerful acoustic signals is proposed, which makes it possible to ensure precise spatiotemporal beam focusing. The introduction of a transverse-coordinate-dependent local wave frequency is suggested, due to which the equality of the formation lengths of a discontinuity for all rays is achieved. This thereby ensures an increase in nonlinear absorption; as a result, the temperature and radiation action of focused ultrasound on the medium increase.
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| 9. |
- Gusev, V. A., et al.
(författare)
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Nonlinear sound in a gas-saturated sediment layer
- 2015
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Ingår i: Acoustical Physics. - : Maik Nauka/Interperiodica. - 1063-7710 .- 1562-6865. ; 61:2, s. 152-164
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Tidskriftsartikel (refereegranskat)abstract
- Wave propagation in a near-bottom layer containing gas bubbles is analyzed. Evolution equations are derived for intense acoustic waves and wave beams in a medium with an inhomogeneous bubble distribution. The field of an intense beam along the axis of the focusing sound channel is calculated. The coefficients of reflection and passage of sound from a homogeneous medium into a bubble layer and back again are calculated. It is shown that the near-bottom layer can effectively trap rays incident on it and ensure a waveguide propagation character. The presence of bubbles increases both the interval of angles at which the wave penetrates the layer and the interval of angles at which rays undergo total internal reflection and do not depart the layer. The acoustic field in the layer from a point source is calculated.
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| 10. |
- Gusev, V.A., et al.
(författare)
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The Field of Radiative Forces and the Acoustic Streaming in a Liquid Layer on a Solid Half-Space
- 2010
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Ingår i: Acoustical Physics. - : Pleiades Publishing. - 1063-7710 .- 1562-6865. ; 56:6, s. 861-870
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Tidskriftsartikel (refereegranskat)abstract
- The acoustic field and the field of radiative forces that are formed in a liquid layer on a solid substrate are calculated for the case of wave propagation along the interface. The calculations take into account the effects produced by surface tension, viscous stresses at the boundary, and attenuation in the liquid volume on the field characteristics. The dispersion equations and the velocities of wave propagation are determined. The radiative forces acting on a liquid volume element in a standing wave are calculated. The structure of streaming is studied. The effect of streaming on small size particles is considered, and the possibilities of ordered structure formation from them are discussed.
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