MA Loudspeakers

MA Loudspeakers at EPFL is connected to plasmacoustic transducers, which generate sound by converting electrical signals into acoustic waves. Instead of a vibrating diaphragm and voice coil, the approach uses local ionisation of air molecules in a controllable, intense electric field within a very thin plasma layer. The ions transfer momentum to air between electrodes and, with an added AC voltage on a constant DC bias, the ionised air compresses to generate sound.

The transducer uses two metallic electrodes: a perforated collector plate and an array of thin emitter wires, fixed on a plastic frame with a 5 mm air gap. A corona discharge is initiated when the electric field exceeds the electric breakdown threshold. The text also describes application areas such as compact broadband sound absorption, non-resonant behaviour without moving parts, and active sound control enabled by an ultra-fast response time.