MEMS speaker


How do USound MEMS speakers work?

USound was the first company to introduce MEMS speakers on the audio market. This article explains how our MEMS speakers work, enabling manufacturers to create highly advanced and customizable audio systems.

Piezoelectricity & USound’s MEMS speakers

USound’s MEMS speakers are based on the piezoelectric effect. Piezoelectricity is the process of using crystals to convert electrical energy into mechanical energy, or vice versa. Crystals with these properties are for example aluminium nitride (AlN) or lead zirconate titanate (PZT). These materials expand or shrink in an electric field.

In a practical configuration, such an electric field is generated between electrodes and applied to a piezoelectric layer. This layer is put on top of a substrate (for example a silicon plate). If an electric field is applied across its electrodes, the top layer contracts and bends both layers upwards.

The bending movement of this so-called cantilever needs to be translated into a one-dimensional piston-like movement in order to be suitable to drive a loudspeaker membrane. To achieve a one-dimensional piston-like movement, multiple bending cantilevers are attached to a central element in a spring structure. In a symmetric arrangement of the cantilevers, the central element will then only move up and down.

To radiate sound, air must be moved. To move more air, the small MEMS structure is connected to a membrane that expands the movement to a larger area.

The result is a system that works just like a standard electrodynamic speaker. Instead of a bulky magnet-coil actuator, the USound MEMS speaker uses integrated piezo-actuators on a MEMS chip to move the membrane and generate sound.

Create the most advanced audio systems for hearables and wearables with USound’s MEMS speakers. Contact our sales department and learn more.