More surprises from graphene. A recent study demonstrates that headsets and loudspeakers made of this innovative material can produce much higher sound quality compared to any hi-fi devices currently available on the market.
Qin Zhou and Alex Zettl, researchers at the University of California at Berkeley, created the first prototype (click here for the results of their work).
The device is made of a thin graphene membrane inserted between two electrodes that generate an electric field. When the field fluctuates, the membrane vibrates, producing sound. This sound is almost perfect for human listening, in that the system is very close to the ideal standard, which provides for constant sound pressure from 20 Hz to 20 kHz, as mentioned in the MIT Technology Review.
The result is due to the graphene membrane, which allows to overcome most of the limits of traditional devices. Most appliances on sale are generally provided with a membrane that needs to have its fluctuation “mitigated” to expand the sound frequency range. The efficiency of an audio amplifier is, in fact, proportional to the so-called damping factor. This is a complicated and expensive operation, which inevitably results into inefficiencies within the system.
One way to address the issue without reducing sound quality is to create an ultra-thin, ultra-light membrane, whose motion is dampened without taking any special engineering measures, but only through air. It is not an easy approach, because the materials tested so far, become brittle when thinning, and therefore unsuited.
On the other hand, graphene has changed all perspectives: ultra-thin and ultra-strong, it allowed the researchers to create a perfect 30nm thick membrane with a 5mm diameter that – dampened by air – can transform all its energy into sound and produce an excellent response to frequencies within the whole hearing spectrum.
Perspectives are more than promising: the technology could soon be launched successfully on the market, particularly in the field of mobile devices, where energy consumption is crucial.
The Editorial Staff
Published on Tuesday, March 19, 2013