Speaking volumes with wafer-thin loudspeakers

Materials World magazine
,
1 Jun 2009
Flat Flexible Loudspeaker

Wafer-thin loudspeakers that project sound further than conventional models could transform public address systems in train stations, airports and shopping centres.

The Flat Flexible Loudspeaker, from engineers at the University of Warwick, UK, is less than 0.25mm thick and emits planar directional sound waves.

‘Its size and flexibility mean it can be used in all sorts of areas where space is at a premium,’ explains Steve Couchman, CEO of Warwick Audio Technologies, a spin-out from the University.

The device is made from a flexible laminate of thin conducting and insulating materials, which vibrate and produce sound when excited by an electrical signal (researchers could not reveal the exact composition of the materials).

‘The whole surface of the speaker moves as a planar piston, therefore the entire diaphragm radiates in phase, forming an area source,’ explains Couchman. Normal cone speakers are considered a ‘point’ source.

‘The wave front emitted by the vibrating surface is phase coherent, producing a plane wave with high directivity and accurate sound imaging. [This] does not attenuate with distance in the same way as a moving coil loudspeaker, enabling sound to be projected over longer distances.’

The speaker is a dipole source, such that both sides reproduce the audio signal so that sound can be heard from all angles.

The company expects to launch its first commercial product later this year.

Further information: Warwick Audio Technologies