Technical Papers and Presentations

Multiphysical simulation is a daily-used tool for loudspeaker design and engineering, however it is still a time expensive process that requires specific modeling capabilities. In order to increase engineering efficiency and to broaden the usage of multiphysical simulation, at Elettromedia s.r.l. we developed a complete software suite for loudspeaker transducer design. The software suite is composed by four applications, each dedicated to a specific aspect of loudspeaker design: i) linear modeling, ii) electromagnetic system, iii) suspension system, iv) vibroacoustic system. All the applications have been developed using COMSOL^® Application Builder and released to Elettromedia electroacoustic design team as Stand-Alone Apps built with COMSOL Compiler™. Those technologies recently introduced in COMSOL Multiphysics^® allowed us to build customized interfaces, precisely tailored to the needs of the electroacoustic design team, and provide an agile environment for fast application deployment.

All the applications rely on a hybrid modeling approach that integrates FEM with lumped models. Various COMSOL^® Modules come into play. The AC/DC Module with the Electrical Circuit interface is used for lumped parameter modeling, and it is coupled with other physics through Variables or External Couplings elements; the Magnetic Fields interface is used to compute the magnetic field and the induced current distributions due to the loudspeaker permanent magnet and to the current injected in the coil. The Solid Mechanics interface is used to model the elastic behavior of the moving parts of the loudspeaker; the coupling between Magnetic Fields and Solid Mechanics interfaces are implemented through a Body Load node and a Lorentz Term node applied to the coil. The Acoustics module with Pressure Acoustics and Thermoviscous Acoustics interfaces are used to model acoustic propagation into a domain terminated with a Perfectly Matched Layer; the acoustic field outside the computational domain is extrapolated by the Exterior Field Calculation node. The Optimization Module is used to implement the estimation of linear transducer parameters from simulation results through Global Least-Squares Objective. A combination of Stationary and Frequency Domain (possibly with Perturbation) Studies is used according to the specific simulation scenario set-up by the user.

The Application Builder is used to implement the applications GUIs: Form Collections and application-specific Methods provide the users the possibility of simulating three virtual prototypes at a time, with automatic overlay of the results, thus facilitating the comparison between different design alternatives. The user can load up to three different geometries and an extensive use of custom Methods enables the management of domain selections among the different imported geometries.

All the applications have been validated through a formal process including: i) training phase to estimate material parameters and their uncertainties based on measurements; ii) uncertainty and sensitivity analysis; iii) test phase based on measurements of loudspeakers not belonging to the training set; iv) computation of accuracy metrics. On average, a prediction error below 5% have been obtained for all applications.