Michael Harper for redOrbit.com – Your Universe Online
One of the coolest scientific advancements of the century is the discovery of graphene. This material is the only two-dimensional element and, when gathered together, it can take on incredibly thin shapes. It’s been called a “super material” because despite it’s incredibly thin and light-weight makeup, it’s also stronger than diamonds or steel and is a great conductor of electricity.
Scientists only learned how to capture graphene and study it in 2004. Prior to that, it was thought to be unstable in its free form. Over the past nine years, the study of graphene has taken off as scientists and researchers begin to use it in a variety of applications. For instance, scientists from the University of California in Berkeley have now created a pair of headphones with graphene diaphragms. While the existence of such a pair of cans is exciting enough for some, the Berkeley scientists should have been prepared for the resulting debates amongst audiophiles.
The common speaker creates sound by running vibrations through a diaphragm, often made of paper. The vibrations of the diaphragm create sound waves. Depending on the speed of these vibrations and the length of the waves (or frequency) the sound can go from high to low.
“For human audibility, an ideal speaker or earphone should generate a constant sound pressure level from 20 Hz to 20 kHz, ie it should have a flat frequency response,” say Qin Zhou and Alex Zettl, both of UC Berkeley, speaking to TechnologyReview.com.
The graphene diaphragms are said to deliver this kind of flat performance naturally and all in a thin and light package.
The headphones are made from just a few layers of super thin graphene sandwiched between two electrodes. These electrodes are responsible for vibrating the graphene layers and thus replicating the sounds.
Graphene’s incredible strength and ability to withstand considerable stress is what Zhou and Zettl were after.
Paper can also generate sound, but it’s an incredibly weak substance. To prevent the paper diaphragms from blowing out at a certain frequency, headphone makers typically dampen the air flow and restrict the level of frequencies handled by the headphones. This dampening is often achieved by making the diaphragm small and thin while keeping the frequencies within a certain range so that the air performs much of the dampening.
This is where graphene is expected to shine in art of sound reproduction.
“It is electrically conducting, has extremely small mass density, and can be configured to have very small effective spring constant,” say Zhou and Zettl. The fact that graphene is also incredibly strong means that it doesn’t need to be dampened and can therefore handle a larger range of frequencies while remaining mostly flat.
Zhou and Zettl compared the new graphene headphones to a pair of Sennheiser MX-400 headphones, a set of headphones which doesn’t live up to the exacting standards of audiophiles but are commonly used by regular listeners.
“Even without optimization, the speaker is able to produce excellent frequency response across the whole audible region (20 Hz~20 KHz), comparable or superior to performance of conventional-design commercial counterparts,” explained Zhou and Zettl.
Graphene is also incredibly efficient, meaning more energy is translated into sound that traditional headphones.
There’s no word on how much these headphones will cost and when they might arrive to market, but once these become a real thing, be sure to catch the audiophile debates on the quality of their sound production.
Source: Michael Harper for redOrbit.com – Your Universe Online
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