I am currently working on an exciting new loudspeaker technology, carbon nanotube (CNT) thin-films. These are thermoacoustic loudspeakers, meaning that they generate sound only by rapidly changing their temperature, as opposed to conventional loudspeakers that generate sound by imparting a velocity on the air around them. A carefully grown, vertically-aligned carbon nanotube forest can be dry-drawn into a thin film that can then be used as a loudspeaker. These new loudspeakers are flexible and stretchable and are nearly weightless when compared to conventional moving coil loudspeakers. Here is an example of a CNT loudspeaker.