This is a demonstration of a soft membrane loudspeaker with near-perfect transparency and frequency response, from 20 Hz to 20 kHz, across the entire audible range. The speaker is placed in front of a laptop screen. An electrical signal from the audio output of the laptop is fed through an amplifier to the loudspeaker. The loudspeaker transforms the electrical signal into sound. Music videos are played from YouTube, where the sound is generated by the transparent loudspeaker in front of the screen. Thickness changes in the soft membrane are induced by electrical signals. These thickness changes can -- in addition to generating sound -- provide localized haptic feedback in front of a screen, where the nearly transparent device will not impede the viewing experience. This video relates to a paper that appeared in the 30 Aug., 2013, issue of Science, published by AAAS. The paper, by Christoph Keplinger at Harvard University in Cambridge, Mass., and colleagues was titled, "Stretchable, Transparent, Ionic Conductors."
[Video courtesy of Christoph Keplinger and Jeong-Yun Sun, Whitesides and Suo Research Groups, Harvard University]