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Drive unit design and modelling


CE Electro-Acoustics offers CAD (COMSOL Multiphysics) for electro-mechanical and acoustic systems, providing custom models for design, analysis, problem solving and performance prediction. Drive units and motors are designed using state of the art electro-magnetic finite element software, providing full solutions for magnetic circuits and motor design, for both static and alternating current (AC) cases. Used for accurate prediction of motor force, magnet efficiency, steel saturation and motor linearity. AC analysis studies the effects of eddy current behaviour and is subsequently used to predict the drive unit's motor frequency response.


Drive units

A design and development service is offered for each of the following drive units types:

  • Subwoofer, woofer, midrange, tweeter and full range drive unit designs
  • Balanced Mode Radiator (BMR) designs, Audio Full Range (AFR) designs.
  • Ultra slim and high aspect ratio designs.
  • Exciter and micro speaker designs
  • Low-profile subwoofer drive units designed to save space and weight, suited to the automotive or 'on-wall' speakers.



AFR and custom low profile, large voice coil designs for automotive and high power, full range applications.






Balanced Mode Radiator (BMR) designs.






High Aspect Ratio Panel, Balanced Mode Radiator (HARP BMR) designs.





AFR and BMR designed by CE Electro-Acoustics in accordance with Tectonic Elements licensing.



Design services include the optimisation and benchmarking of drive units, motors and exciters. Several examples are shown below:


An FEA example of a motor, showing field lines within the steel of the motor circuit:

Magnet - light blue (region 3)
Voice coil - red (region 4)
Steel - dark blue (regions 1 and 2)






A basic magnet design study looking at a motor's force displacement (Bl).







A more in-depth study looking at eddy current behaviour and its effect on the terminal impedance of a motor.

The alternating field from the voice coil permeates the inner pole piece of the motor structure at high frequency (10kHz). A Faraday shield (light blue - copper - region 6) spans from top to bottom on the outer side of the voice coil (red - region 4), efficiently 'shielding' the adjacent steel.





Following on from the above model, the FE results can be compared to the realised motor. The yellow trace shows the predicted performance. Overlaid, shown in pink and purple, is the measured terminal impedance of the realised design, with the voice coil free and clamped respectively.