Tokai Rubber Industries has developed what it claims to be the world's first all-rubber speaker, a gadget that may revolutionize the music listening experience.

In creating the novelty speaker the Japanese company used a special kind of rubber it calls "smart rubber," which is able to conduct electricity. In a speaker, the ability to conduct electricity means the ability to produce sound.

Tokai Rubber placed a layer of non-conductive rubber between two rubber electrodes, and generated static electricity by applying sufficient voltage. That static energy, in turn, caused the speaker to contract, expand, and vibrate. The repeated expansion and contraction of the rubber sheet produces sound waves.

Tokai's newly developed technology basically allows rubber electrodes to have a static charge over the surface. According to the company, the insulating rubber sheet should not change its resistance when it's expanded.

"Of course, technology is needed to make rubber conduct electricity," said Tokai. "What our technology does is give the rubber a uniform surface charge. Another thing needed is insulating rubber between the pieces of conductive rubber. Each type of rubber has to be flexible, and the insulating rubber mustn't change its resistance when it expands. That's a key technology in this speaker."

"Wearing headphones is a bit of a hassle," added the company, "so we'd like to use the flexibility of this speaker to build into chairs and the like. That way, people could enjoy audio in open settings."

The real benefit here, however, is the smart rubber's application as artificial muscles. Further exploiting its potential could lead to amazing innovations, including robots capable to respond and move as quickly and naturally as humans.

Tokai introduced its unique rubber speaker at the Combined Exhibition of Advanced Technologies (CEATEC) show in Japan, Asia's biggest gadget fair. The company does not have a clear roadmap for its new product, but said it is conducting surveys and talking to potential customers.

"Currently, we don't have a specific product roadmap. We'd like to think about needs and applications together with potential customers, including those at CEATEC. Then, we'd like to turn this speaker into a commercial product."

Tokai Rubber Industries had earlier launched rubber touch sensors, which enabled the company to introduce a new development line exploiting materials for artificial muscles. The speakers were all piezoelectric and film types until now, and they were unable to produce lower frequencies. The new rubber speakers, however, can produce those lower frequencies as well.