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Our friend nanotechnology has produced a flexible, stretchable, transparent material thinner than paper that can be used as a speaker. This new material can be inserted into clothing, wallpaper, right into the ears or onto windows. The material has been developed by Chinese scientists and is made up of carbon nanotube films and could be used to produce the world?s thinnest speakers.

The new carbon material, which is 1/1000th the width of a human hair can produce sound with the ?same quality of conventional speakers? but does not require magnetic drivers or any moving parts at all. This means that it can fit almost anywhere. I?d love to walk down the street in my speaker-shirt playing this or better still this.

Here is a video of the material embedded onto a moving, flexible flag. It?s plugged into the researcher?s ipod.
http://www.youtube.com/watch?v=8aoflVUvwlQ

My mind boggles at the potential applications of this material. Speakers on walls, speakers in hats, in bike or motorcycle helmets or on your shirt?. how about SUPER small earbuds, sound right from your tv screen or the ultimate bling - a popped shirt collar that produces music.

Here is the abstract from the report that is to be presented on Dec 10th:

We found that very thin carbon nanotube films, once fed by sound frequency electric currents, could emit loud sounds. This phenomenon could be attributed to a thermoacoustic effect. The ultra small heat capacity per unit area of carbon nanotube thin films leads to a wide frequency response range and a high sound pressure level. On the basis of this finding, we made practical carbon nanotube thin film loudspeakers, which possess the merits of nanometer thickness and are transparent, flexible, stretchable, and magnet-free. Such a single-element thin film loudspeaker can be tailored into any shape and size, freestanding or on any insulating surfaces, which could open up new applications of and approaches to manufacturing loudspeakers and other acoustic devices .

source

Another article on this

Carbon nanotube speaker makes sound, but no vibrations


Nov. 3, 2008

While carbon nanotubes are widely praised for their strength and electrical properties, no one has thoroughly investigated their acoustic properties, until now. A team of Chinese researchers has found that zapping sheets of carbon nanotubes with an electric current causes the nanotubes to emit sound.


The team, which consists of scientists Shoushan Fan and colleagues at Tsinghua Univ. in Beijing, China, and Beijing Normal Univ., hope that the discovery could lead to the development of cheap, flat loudspeakers. To create the nanotube speaker, the researchers sent an audio frequency current through a thin sheet of carbon nanotubes, generating a sound. Unlike standard loudspeakers that generate sound by vibrations in the surrounding air molecules, the nanotube speaker doesn´t emit vibrations. The team used a laser vibrometer to detect vibrations in the sheet, but found nothing.

Instead, the nanotube speaker likely works as a thermoacoustic device: when an alternating current passes through the sheet, the sheet experiences rapid temperature oscillations alternating between room temperature and 80°C (176°F). These temperature oscillations cause pressure oscillations in the surrounding air, producing the sound, while the nanotube sheet remains static. One advantage of this method is that, even if part of the nanotube sheet breaks, it should continue to emit sound, unlike conventional speakers.

This thermoacoustic phenomenon was actually discovered in the late nineteenth century, when scientists passed a current through a thin foil to produce sound, leading to the invention of the "thermophone." Although the principle is the same, however, the nanotube sheet acts much more efficiently than foil because it doesn´t require nearly as much applied heat to increase its temperature. Specifically, the nanotube sheet´s heat capacity is 260 times smaller than platinum foil, making nanotubes 260 times more efficient and able to produce a louder sound.

The Chinese researchers envision several interesting applications for the nanotube speakers. Because the nanotube sheets can be stretched to be visually transparent and still produce sound, they might be fitted over the front of an LCD screen to replace conventional speakers. Another possibility is incorporating the nanotube speakers into textiles to create musical clothes.

Can you imagine having this stuff on the ground of concert venues?