Researchers at the University of California, Berkeley have created the first ever graphene audio speaker: an earphone. In its raw state, without any kind of optimization, the researchers show that graphene’s superior physical and electrical properties allow for an earphone with frequency response comparable to or better than a pair of commercial Sennheiser earphones.
In Berkeley’s graphene earphone, the diaphragm is made from a 30nm-thick, 7mm-wide sheet of graphene. This diaphragm is then sandwiched between two silicon electrodes, which are coated with silicon dioxide to prevent any shorting if the diaphragm is driven too hard.
Whereas most diaphragms/cones must be damped (padded, restricted) to prevent undesirable frequency responses, the graphene diaphragm requires no damping. This is because graphene is so strong that the diaphragm can be incredibly thin — and thus very light. Instead of being artificially damped, the graphene diaphragm is damped by air itself. As a corollary, the lack of damping means that the graphene diaphragm is also very energy efficient...
I would like earphones like that.
I expect the next stop would be the application of graphene to full sized speaker drivers, probably starting with tweeters. Extremely stiff and light cone materials have been a constant pursuit for high-end speaker manufacturers such as Magico and YG Acoustics (among MANY others). Indeed, YG is famous for creating their driver cones out of billet aluminum!
It will be interesting to see how this develops.