Yamaha has developed a prototype speaker that's made of cloth and just 1 millimeter thick.

The prototype speaker, which is on display at the Ceatec exhibition in Chiba, Japan, this week, is made of nonwoven cloth and a metallized film, said Kunimasa Muroi, general manager of Yamaha's Center for Materials and Components Technologies.

The speaker, which is printed with information about the Ceatec exhibition, looks like a very large poster hanging from a long frame. When visitors stand on one side or another of the speaker, they cannot here any sound. But when they walk in front of the speaker, they can hear the sound of a woman speaking.

There is also no overlap in sound when two speakers hang side by side, playing different audio files. When a user stands in front of one speaker, they cannot hear what's being said on the other one. But by walking one or two steps to stand in front of the second speaker, they can listen to that audio file without being disturbed by the sound playing on the first speaker.

The highly directional nature of the sound produced by the speaker is due to its shape, which produces sound waves that are flat instead of curved, Muroi said, saying the speaker is well-suited for advertising or informational posters.

The materials used to make the speaker make it very light. A speaker measuring one meter square weighs 250 grams, Muroi said.

Because the speaker is made of cloth, it can be printed with any image or design using any standard printing process, such as silk screening or an inkjet printer, he said.

Yamaha has yet to decide whether or not to turn the prototype speaker into a commercial product.