MEMS based speakers - sounds good?!

Miniaturized speakers have become the central key for multiple fields of audio technology comprising smartphones, hearing aids, and miniaturized headphones, to name only a few. Generally, loudspeakers must be precisely manufactured at high quantity and at relatively low costs and need to be significantly scaled down to reduce the overall size of the devices, their weight, and the overall power consumption. Here, micro- and nanointegration technologies are driving forces, but were ignored for several years for loudspeaker design and assembly. In this paper, we present a critical discussion of MEMS loudspeaker miniaturization based on finite element and electroacoustic simulations, actuation material choices with emphasis on micro- and nanointegration, and production aspects.