Researchers at the University of California in Berkeley announced the creation of world's first graphene-based audio speaker. It's an earphone with diaphragm made from a 30nm-thick, 7mm-wide sheet of graphene.
Interestingly, even without any optimizations, the graphene earphone is already superior to commercially available earphones such as the Sennheiser MX-400.
The completely untuned, unoptimized graphene speaker performs amazingly in terms of
frequency response and also in terms of energy efficiency.
Given graphene’s status as a wonder material we shouldn’t really be surprised, but it turns out that this graphene speaker — the first of its kind — has intrinsically excellent performance. As you can see in the graph above, the graphene earphone’s frequency response is superb. The reason for this is down to the graphene diaphragm’s simplicity: 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 — which could be important for reducing the power usage of smartphone and tablet speakers.