Roll up, roll up

Loudspeakers that can be folded or rolled up have been developed by the
Korean Advanced Institute of Science and Technology. The loudspeakers feature a
thin film of piezoelectric material which vibrates when fed electric audio
signals. Previous attempts to develop piezo diaphragms have produced
tinny-sounding loudspeakers because low-frequency vibrations cause the metal
electrodes to break away from the film. The researchers have solved the problem
by using platinum electrodes and a special bonding technique, allowing low
frequency vibrations.