共查询到19条相似文献,搜索用时 218 毫秒
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采用全面最小二乘法测量开口箱扬声器系统低频特性参数 总被引:2,自引:0,他引:2
本文分析并建立了开口箱扬声器系统的自回归平均(ARMA)模型参数与低频特性参数的关系,采用全面最小二乘(TLS)法辨识开口箱扬声器系统的ARMA模型参数,从而在时域上测出了开口箱扬声器系统的低频特性参数、阻抗曲线和低频响应曲线,取得了较好的结果。 相似文献
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本文在求解扬声器锥形振膜低频振动的基础上,得到了计算扬声器锥壳环反谐振频率的精确公式,并借助特征频率反比于质量平方根的物理概念,推出了适于工程应用的近似公式,其偏差在3%以内。 相似文献
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扬声器和扬声器系统 扬声器是将电信号转变为声信号并向空间辐射声波的部件.两只或多只扬声器和必需的扬声器箱、分频网络、衰减器等的组合称为扬声器系统.这时其中单只扬声器就称为扬声器单元.迄今为止,扬声器或扬声器系统仍然是高保真立体声系统中音质最不完善的环节.由于扬声器的品种很多,音质又涉及主观感觉,因此还没有明确的评价标准.但是人们只要把大口 相似文献
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The Transmission Line loudspeaker is an audio loudspeaker enclosure topology devoted to extending the low frequency range near the loudspeaker frequency resonance. A few models based on physical properties of damped pipes have been proposed to characterize the Transmission Line loudspeaker systems. Unfortunately, Thiele/Small parameters, which are usually employed in enclosure designs, are not useful as parameters of design for these loudspeakers. In this paper, a comprehensive numerical formulation of a Transmission Line loudspeaker is presented, which is based in a finite difference approach of the governing equations, including the effects of the absorbing material allocated inside the pipe. The influence of the main empirical parameters is tested on the proposed model, which is also compared to a real prototype for validation purposes. 相似文献
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扬声器异常音的快速检测方法及其实验研究 总被引:3,自引:0,他引:3
提出了一种对扬声器声响应中的低阶次谐波失真与高阶次谐波失真和进行综合分析的方法,以实现对扬声器异常音的快速检测。文章分析了扬声器异常音的时域和频域特征,并对人耳听测异常音的机理进行了讨论。通过对扬声器系统Volterra建模并选择连续对数扫频信号作为激励信号,推导出了该模型在此激励下的响应表达式.该表达式揭示了提取各阶冲激响应的方法,由该表达式给出一种可以快速提取各阶次谐波失真的跟踪滤波器,以实现对扬声器异常音的检测。实验室测试和多次工厂生产线测试初步验证了该方法的准确性、快速性和可行性。 相似文献
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提出了一种具有负模量特性的新型声学超结构,并揭示了其低频带隙的形成及拓宽机理.通过理论推导给出了该新型结构的归一化有效模量表达式,由于有效模量的零值点与系统参数密切相关,可以调节合适的参数使得零值点降低或带隙下界降低,进一步实现低频带隙.理论结果表明,在一定的频率范围内,系统的弹性模量为负且负模量区域进一步拓宽,从而通过负模量区域的放大而拓宽带隙.这种新的实现低频带隙的方法克服了传统局域共振附加质量过大及惯性放大结构带隙较窄的缺点.同时,通过有限元法得到的周期结构的传输率随着结构参数的变化趋势与理论分析的变化趋势基本一致,并得到了约40—180 Hz的低频宽带.这种实现低频带隙的新思路对低频声波的控制具有很重要的理论指导意义. 相似文献
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In this paper, the phenomenon of band gap transmission in high temperature plasma is studied. Cold plasma has high pass property, so the low-frequency electromagnetic wave cannot penetrate plasma and propagate in it. Simulation results show that in high temperature plasma, a transmission peak will be produced in the low frequency band where the band gap is supposed to occur due to the influence of the external magnetic field and the electron temperature. Through the study of the frequency and the amplitude of the transmission peak, it is found that the frequency of the peak is related to the collision frequency and the magnetic field, and the amplitude of the peak is related to the electron temperature and the thickness of the plasma slab. The calculation formula of peak frequency is obtained by fitting the obtained data. The fitting formula is validated by the analytic solution, and the results show that the two methods are in good agreement. 相似文献
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I.IntroductiollThecomputeraideddesign(CAD)techniqueisanadvancedmethodforthedesignofvented-boxloudspeakersystemsI1l,whichisbasedontheThiele-Sma.llparametersofloudspeakersIa]andthefowfrequencycharpeteristicparametersofvelltedboxloudspeakersystems.TheThiele-Smallparametersofloudspeakersandsomeofthelowfrequellcycharacteristicparametersofvellted-boxloudspeakersystemshavebeendeterIIilnedbyfrequencyUomainmeth.dI3'4]foralongtime.Themaindisadwtagesofthismethodarecomplicatedandtimeconsuming.TheThi… 相似文献
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在实际应用中,通常需要将多个声人工结构单元进行组合来实现低频宽带的隔声降噪。这种组合结构往往参数较多,传统的设计方法很难对其进行高效的自动化设计。本文在集总参数模型的基础上,提出了一种基于深度学习的低频宽带隔声器件设计方法,并基于该方法完成了由9个二阶亥姆霍兹共鸣器单元组合而成的低频宽带隔声装置的设计。仿真结果表明,该隔声装置在158 Hz~522 Hz范围内均具有良好的隔声效果,从而验证了所提出方法的有效性。与传统方法相比,本文所提出的设计方法不仅减少了对设计者专业知识和设计经验的依赖,而且具有更高的设计效率,更强的通用性,未来有望进一步推广至其他声人工结构的设计领域。 相似文献
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A study of the targeted energy transfer (TET) phenomenon between an acoustic resonator and a thin viscoelastic membrane has recently been presented in the paper [R. Bellet et al., Experimental study of targeted energy transfer from an acoustic system to a nonlinear membrane absorber, Journal of Sound and Vibration 329 (2010) 2768-2791], providing a new path to passive sound control in the low frequency domain where no efficient dissipative device exists. This paper presents experimental results showing that a loudspeaker used as a suspended piston working outside its range of linearity can also be used as a nonlinear acoustic absorber. The main advantage of this technology of absorber is the perspective to adjust independently the device parameters (mass, nonlinear stiffness and damping) according to the operational conditions. To achieve this purpose, quasi-static and dynamic tests have been performed on three types of commercial devices (one with structural modi?cations), in order to de?ne the constructive characteristics that it should present. An experimental setup has been developed using a one-dimensional acoustic linear system coupled through a box (acting as a weak spring) to a loudspeaker used as a suspended piston acting as an essentially nonlinear oscillator. The tests carried out on the whole vibro-acoustic system have showed the occurrence of the acoustic TET from the acoustic media to the suspended piston and demonstrated the efficiency of this new kind of absorber at low frequencies over a wide frequency range. Moreover, the experimental analyses conducted with different NES masses have con?rmed that it is possible to optimize the noise absorption with respect to the excitation level of the acoustic resonator. 相似文献
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The band-limited linear predictive coding (BLPC) vocoder-based adaptive feedback cancellation (AFC) removes the high-frequency bias, while the low frequency bias persists between the desired input signal and the loudspeaker signal in the estimate of the feedback path. In this paper, we present a BLPC vocoder-based adaptive feedback canceller with probe noise with an objective of reducing the low-frequency bias in digital hearing-aids. A step-wise mathematical analysis of the proposed feedback canceller is presented employing the recursive least square and normalized least mean square adaptive algorithms. It is observed that the optimal solution of the feedback path is unbiased for an unshaped probe noise, but is biased for a shaped probe signal; the bias term does not consist of correlation between the desired input and the loudspeaker output. The identifiability conditions are analysed and it is shown that a delay, greater than or equal to the length of the adaptive filter, must be introduced in the forward path to achieve an unbiased feedback path estimate. Algorithm analysis and computer simulations presented in this paper justify the reason for selecting the proposed design over the existing BLPC vocoder-based feedback cancellation algorithm. 相似文献