Headphone and Speaker Design
Virtual prototyping and design optimisation, using numerical simulations, can greatly accelerate speaker design for products such as headphones, loudspeakers and smartphones. The dynamics of speakers and their interaction with air require models that consider the complex interactions of electromagnetic components in the driver, structural behaviour of the house, the geometry of the acoustic environment and the effects of waveguides when present. Other factors that may be important include the acoustic impedance of soft components such as human skin and thermal and viscous acoustic losses. These factors can be modelled using a multiphysics approach to optimise the design of speakers with respect to output level, frequency response and total harmonic distortion.
An example of Xi’s experience is the development of high quality headphones based on single-sided electrostatic actuation of an ultra-thin diaphragm. The client company had substantial mechanical, electrical and acoustic experience but required assistance with simulation. Their device operated by applying DC bias and AC drive voltages to a tensioned diaphragm parallel to a wire mesh ground plane. The speaker included many design elements that affect the acoustic performance including the AC and DC levels, thickness of individual elements, their material properties, pre-tension levels and the overall geometry. Numerical simulation helped the client avoid the time and cost related to physically prototyping and testing every one of these design elements. The client was also able to use the simulation to quickly assess proposed changes due to unforeseen supply line challenges, allowing the design to involve without halting the mass production phase of roll-out.