Abstract: In this paper, the specific sound Transmission Loss
(TL) of the Laminated Composite Plate (LCP) with different material
properties in each layer is investigated. The numerical method to
obtain the TL of the LCP is proposed by using elastic plate theory. The
transfer matrix approach is novelty presented for computational
efficiency in solving the numerous layers of dynamic stiffness matrix
(D-matrix) of the LCP. Besides the numerical simulations for
calculating the TL of the LCP, the material properties inverse method
is presented for the design of a laminated composite plate analogous to
a metallic plate with a specified TL. As a result, it demonstrates that
the proposed computational algorithm exhibits high efficiency with a
small number of iterations for achieving the goal. This method can be
effectively employed to design and develop tailor-made materials for
various applications.
Abstract: The sound pressure level (SPL) of the moving-coil
loudspeaker (MCL) is often simulated and analyzed using the lumped
parameter model. However, the SPL of a MCL cannot be simulated
precisely in the high frequency region, because the value of cone
effective area is changed due to the geometry variation in different
mode shapes, it is also related to affect the acoustic radiation mass and
resistance. Herein, the paper presents the inverse method which has a
high ability to measure the value of cone effective area in various
frequency points, also can estimate the MCL electroacoustic
parameters simultaneously. The proposed inverse method comprises
the direct problem, adjoint problem, and sensitivity problem in
collaboration with nonlinear conjugate gradient method. Estimated
values from the inverse method are validated experimentally which
compared with the measured SPL curve result. Results presented in
this paper not only improve the accuracy of lumped parameter model
but also provide the valuable information on loudspeaker cone design.
Abstract: The nonlinear damping behavior is usually ignored in
the design of a miniature moving-coil loudspeaker. But when the
loudspeaker operated in air, the damping parameter varies with the
voice-coil displacement corresponding due to viscous air flow. The
present paper presents an identification model as inverse problem to
identify the nonlinear damping parameter in the lumped parameter
model for the loudspeaker. Theoretical results for the nonlinear
damping are verified by using laser displacement measurement
scanner. These results indicate that the damping parameter has the
greatly different nonlinearity between in air and vacuum. It is believed
that the results of the present work can be applied in diagnosis and
sound quality improvement of a miniature loudspeaker.