Balanced Armature Transducer — Time Domain Analysis
Application ID: 110091
This is a full vibro-electroacoustic simulation of a balanced armature transducer (BAT or also known as a receiver in some industries) which is a high-performance miniature loudspeaker often used in hearing aids and other in-ear audio products such as earbuds.
The model is set up and solved in the time domain using a DC analysis of the magnetic system as initial condition for the AC transient problem. The electromagnetic coupling to the armature is done using the built-in Magnetomechanical Forces multiphysics coupling. Moving Mesh is used to capture any nonlinear effects that are due to changes in the geometry such as magnetic gaps and nonlinear thin-film damping. The Moving Mesh also captures the structure to EM coupling (back EMC) which comes from the varying air gap in the magnetic flux circuit, that is, a varying reluctance.
The vibrating armature is part of a magnetic circuit with alternating flux imposed by the AC coil – causing a strong interaction with the unidirectional permanent (DC) magnetic field in the gap.
The measurement setup that consists of a tube and an ear canal simulator (a so-called 711 coupler) is modeled through a time-domain MOR where the input impedance to the system is expressed in terms of it sum of partial fractions. This results in a detailed electrical circuit representation of the test setup. See the Input Impedance of a Tube and Coupler Measurement Setup: Time-Domain MOR Using Partial Fraction Fit model for details. Moreover, the radiation impedance of the small vent, connecting the back-volume to the exterior, is based on a sub-model, computed in Radiation Impedance of a Small Vent.
A frequency domain version of the model is analyzed in Balanced Armature Transducer — Frequency Domain.
This model example illustrates applications of this type that would nominally be built using the following products:
however, additional products may be required to completely define and model it. Furthermore, this example may also be defined and modeled using components from the following product combinations:
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