标题: 利用振动吸震器理論做动态扬声器之低频延伸设计
Low-frequency Extension of Dynamic Loudspeakers Based on The Theory of Vibration Absorber
作者: 张寰生
白明宪
机械工程学系
关键字: 喇叭设计;低频延伸;微型扬声器;低音喇叭;共振式喇叭;振动吸震器理论;喇叭最佳化;vibration absorber theory;microspeaker;subwoofers;resonant loudspeaker;vented-box;loudspeaker optimization
公开日期: 2006
摘要: 本论文着重在扬声器的低频延伸设计,从微型扬声器到中大型的扬声器都在本文探讨的范围里。设计方法为利用传统的vented-box结构,并找出最佳的音箱几何尺寸,此时相当于机与声两个系统间有偶合效应的2自由度振动系统,这个系统和振动学中的振动吸震器理论非常相似,所以可以把振动吸震器理论应用在这里。分析的平台是利用机电声类比电路,并使用电路学中方法,来求得扬声器的电阻抗和轴向声压。为了建立一套针对vented-box的设计流程,所以先跟据振动吸震器理论来求出特征方程式,利用此式来画一设计图表,这样一来即可利用此图表来做设计。除此之外,还可以进一步的使用这个图表来做限制条件下的最佳化设计。本论文主旨即在列出上述的设计准则和方法。
A universal design procedure is presented for enhancing the low-frequency responses of loudspeakers ranging from handset microspeakers to subwoofers. This procedure aims at finding the optimal parameters of vented-box configuration using a systematic procedure based on vibration absorber theory. By viewing the system as two coupled serial and parallel oscillators, a characteristic equation is derived for the vented box system. A simulation platform is then established using electro-mechano-acoustical (EMA) analogous circuits. Electrical impedance and on-axis sound pressure level (SPL) of the loudspeaker can be simulated by solving the loop equations of the analogous circuit. In order to facilitate the design process of such loudspeaker systems, a design chart is devised using the characteristic equation for deciding the parameters to deliver maximal output at the low-frequency end. In addition, a constrained optimization procedure is applied to maximize the acoustic output under the enclosure constraints. Simulations and experiments were undertaken for validating the resulting optimal design. Design guidelines are summarized.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT009414593
http://hdl.handle.net/11536/80992
显示于类别:Thesis