Pei Yu, Yong Shen^*, Ziyun Liu

Sound & Vibration, Vol.52, No.5, pp. 6-11, 2018, DOI:10.32604/sv.2018.04090

Abstract A lot of work has focused on compensating nonlinear distortions of the microspeaker under large excitation, yet it is unclear at which level the effect of nonlinear distortion is imperceptible or not annoying. In this study virtual listening tests were performed to evaluate the deterioration of sound quality in music signals with different levels of nonlinear distortion by a microspeaker. Binaural recordings of the music played by the microspeaker were made at different voltage levels, adjusted to the same RMS power, and afterwards reproduced by a low distortion reference headphone. The “double-blind triple-stimulus with hidden reference” method was used in… More >

Claude Prost^{1, *}, Bruno Abdelnour²

Sound & Vibration, Vol.52, No.5, pp. 2-5, 2018, DOI:10.32604/sv.2018.00002

Abstract Tall and slender substation equipment is prone to failure under seismic excitations. The consequences of such failure can be devastating and lead to weeks or months of lost power.
The IEEE Std 693-2005 ensures that all substation equipment installed in high seismic areas are designed to withstand earthquakes of a severity related to that area.
There are numerous ways to increase the seismic strength of substation equipment and this paper will discuss doing so by base isolation, specifically using wire rope isolators (WRIs).
It is the purpose of this paper to present a case study in which the Socitec Group… More >

Xinggang Jiang^{1, 2}, Xianbin Zhu¹, Shanda Li³, Daxi Geng^{1, 2, *}, Deyuan Zhang^{1, 2}

Sound & Vibration, Vol.52, No.6, pp. 23-28, 2018, DOI:10.32604/sv.2018.03929

Abstract The sandwich transducer structure is comprised of three components along its main axis: the back metal cap, piezoelectric ceramic stack and the horn. The purpose of this work is to present a simplified method, referred as the equivalent length algorithm, to design the actuator parameters including each segment length and the resonance frequency f_s. The actuator length L and the propagation wavelength λ along its main axis satisfy the standing wave theory. So, define an equivalent length coefficient for each part of the actuator, and then the sandwich structure is regarded as a single material cylindrical rod with equivalent length… More >

Xiaoli Zhong^{1, 2}, Wenying Guo¹, Jie Wang²

Sound & Vibration, Vol.52, No.6, pp. 18-22, 2018, DOI:10.32604/sv.2018.03900

Abstract Early reflection is an important component in an enclosed sound field. Due to the precedence effect, the early reflection may not be the dominant factor in sound source localization; however, it still has obvious influences on spatial position, loudness, timbre, and etc. Till now, there have sparse studies on evaluation of the audible threshold of early reflections with lacking of general and quantitative results. This work investigated the audible threshold of early reflection with a simplified sound field model under various experimental conditions including the combination of eight incidence angles and five time delays. Three-down-one-up adaptive strategy with three-interval three-alternative… More >

Jianguo Ma^{1, 2}, Changgeng Shuai^{1, 2}, Yan Li^{1, 2}

Sound & Vibration, Vol.52, No.6, pp. 11-17, 2018, DOI:10.32604/sv.2018.03893

Abstract The design and optimization of actuators are difficult and critical for the active-passive hybrid vibration control system. In this paper, an electromagnetic actuator model is established based on Ohm’s Law for magnetic circuit considering the leakage flux. The 600N electromagnetic actuators are designed and optimized based on ANSYS simulation according to the engineering request. Its transient characteristics are studied. The effects of different structural parameters on its output force are analyzed. The experimental results show that the structure parameters and output force characteristics of the designed electromagnetic actuators satisfy the practical requirement. More >

Lamia Bouafif¹, Noureddine Ellouze²

Sound & Vibration, Vol.52, No.6, pp. 2-10, 2018, DOI:10.32604/sv.2018.02410

Abstract Sound indexing and segmentation of digital documents especially in the internet and digital libraries are very useful to simplify and to accelerate the multimedia document retrieval. We can imagine that we can extract multimedia files not only by keywords but also by speech semantic contents. The main difficulty of this operation is the parameterization and modelling of the sound track and the discrimination of the speech, music and noise segments. In this paper, we will present a Speech/Music/Noise indexing interface designed for audio discrimination in multimedia documents. The program uses a statistical method based on ANN and HMM classifiers. After… More >

Bin Chen^{1, *}, Shuyue Yu¹, Yan Gao²

Sound & Vibration, Vol.52, No.4, pp. 21-27, 2018, DOI:10.32604/sv.2018.03974

Abstract Investigations into active noise control (ANC) technique have been conducted with the aim of effective control of the low-frequency noise. In practice, however, the performance of currently available ANC systems degrades due to the effects of nonlinearity in the primary and secondary paths, primary noise and louder speaker. This paper proposes a hybrid control structure of nonlinear ANC system to control the non-stationary noise produced by the rotating machinery on the nonlinear primary path. A fast version of ensemble empirical mode decomposition is used to decompose the non-stationary primary noise into intrinsic mode functions, which are expanded using the second-order… More >

Qian Kong¹, Genshan Jiang^{1, 2, *}, Yuechao Liu¹

Sound & Vibration, Vol.52, No.4, pp. 9-20, 2018, DOI:10.32604/sv.2018.03749

Abstract The temperature field distribution directly reflects the combustion condition in a furnace．In this paper, acoustic thermometry to reconstruct temperature distribution is investigated. A method based on radial basis function approximation with polynomial reproduction (RBF-PR) is proposed in order to improve the accuracy and stability of the method based on RBF approximation. In addition, the refraction effect of sound wave paths is considered in the process of reconstruction. The curved lines with refraction effect are numerically calculated by solving differential equations, which show that sonic waves curve towards the zones of higher temperature. The reconstructed performance is validated via numerical simulation… More >

James D. Barnes¹, Ethan R. Brush¹, Mark S. Newmark¹, Eric E. Ungar^{1, *}

Sound & Vibration, Vol.52, No.4, pp. 6-8, 2018, DOI:10.32604/sv.2018.03737

Abstract Pressure and proximity measurements made in a tunnel indicate that a typical vehicle passage produced on the tunnel roof an initial pressure increase of small magnitude, followed by a sharp and more substantial drop in pressure below atmospheric. The magnitude of the pressure drop was found to increase with smaller clearances between the vehicle top and the tunnel roof, consistent with the Bernoulli relation and the vehicle speed. The dynamic pressures potentially may have significant effects on the vibration and noise environments on the lower floors of “air rights construction” buildings that span highways. More >

Changgeng Shuai^{1, 2}, Shike Zhang^{1, 2}, Jiaxuan Yang^{1, 2}, Sitong Zhou^{1, 2}

Sound & Vibration, Vol.52, No.4, pp. 2-5, 2018, DOI:10.32604/sv.2018.03724

Abstract Advanced array processing approaches require accurate knowledge of the location of individual element in a sensor array. Most array shape estimation methods require the directions of sources. In this paper, an array shape estimation method based on eigen-decomposition is presented. The directions of sources do not need to be considered in advance and optimal array shape is generated through a series of iterations. To further improve the accuracy of this algorithm, a partitioned eigenstructure method is introduced. Numerical simulations using non-partitioned and partitioned method are conducted to verify the performance of the proposed technique. More >