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First Graphene Speaker Challenges Traditional Designs

By Wesley Fenlon

Fresh from the lab, a graphene diaphragm compares favorably to century-old speaker design.

Wikipedia's page for graphene, science's latest carbon wonder material, stretches on and on and on. The table of contents is insane, and a big chunk of it is dedicated to graphene's potential applications. It has the potential to improve integrated circuits, transistors, solar cells, ultracapacitors, and more. That "more" apparently includes speakers: Researchers at the University of California, Berkeley just created a graphene-based earphone with sound quality equal to a pair of Sennheiser MX400s.

Image Credit: Center of Integrated Nanomechanical Systems, Berkeley

Granted, those Sennheisers aren't top-shelf audiophile gear. They only cost about $15 when they were new. But Berkeley's researchers have created the first graphene diaphragm, and it's already competitive with technology that's been in uses for a century. Speaker cones or diaphragms are traditionally made from paper. As Extreme Tech summarizes, that speaker is vibrating, producing sound. The better the speaker, the more consistent that vibration will be across the human range of hearing. When a speaker isn't consistent, you end up great bassy sound but poor high range sound, or weak bass, or some other imbalance.

While most speaker materials have to be dampened to prevent vibration at certain frequencies, the graphene material is so thin it's dampened by air itself.

The graphene diaphragm measures a mere 30 nanometers thick and is sandwiched between silicon electrodes. When those electrodes produce an oscillating electrical field, the diaphragm vibrates and produces sound. The diaphragm's thinness is what sets it apart--while most speaker materials have to be dampened to prevent them from vibrating too much at certain frequencies, the graphene material is so thin, it's dampened by the air itself.

A comparison to the Sennheiser MX400s shows how impressively consistent the graphene diaphragm is across the range of human hearing. Is graphene going to replace existing speaker technology immediately? Of course not. But this is their first stab at it, and a few more years of research and tuning could potentially make the material perform more consistently. Speaker and headphone companies better take notice--paper might not be the go-to material for too much longer.