Berkeley creates the first graphene earphones, and (unsurprisingly) they’re awesome
Mar 14, 2013 at 12:29 AM Thread Starter Post #1 of 9

Kroc

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http://www.extremetech.com/electronics/150646-berkeley-creates-the-first-graphene-earphones-and-unsurprisingly-theyre-awesome
 
 
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graphene-earphone-diaphragm-640x353.jpg

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.
A loudspeaker (or earphone or headphone) works by vibrating a (usually) paper diaphragm (aka a cone), creating pressure waves in the air around you. Depending on the frequency of these waves, different sounds are created. Human ears, depending on their age, can usually hear frequencies between 20Hz (very low pitch) and 20KHz (very high). Generally, the quality of a speaker is defined by how flat its frequency response is — in other words, whether it produces sounds equally well, no matter where they fall on the 20Hz to 20KHz scale. A poor speaker, or, say, a bassy set of headphones, might be very strong in the lower ranges, but weaker at the top. (See: In search of the perfect headphones.)

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. By applying power to the electrodes, an electrostatic force is created, which causes the graphene diaphragm to vibrate, creating sound. By oscillating the electricity, different sounds are created.
Graphene earphone frequency response (top), vs. Sennheiser MX-400 earphones (bottom)

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.
Remember, we are talking about a completely untuned, unoptimized earphone, and yet its frequency response is superior to a magnetic coil speaker that has been the target of decades of research and development. If that wasn’t exciting enough, the researchers say that their method of growing graphene with chemical vapor deposition can easily be scaled to produce larger diaphragms and thus larger speakers. In all likelihood, following some more research, graphene will go on to become the material of choice for studio speakers — and hopefully, cost permitting, consumer speakers and earphones as well.
Now read: Hype-kill: Graphene is awesome, but a very long way from replacing silicon
Research paper: arXiv:1303.2391 - “Electrostatic Graphene Loudspeaker”

 
Mar 14, 2013 at 8:46 AM Post #2 of 9

TimPrice

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I hope it becomes revolutionary instead of just an alternative...
 
http://www.reddit.com/r/science/comments/1a8adl/berkeley_creates_the_first_graphene_earphones_and/
 
Sep 1, 2013 at 8:06 AM Post #5 of 9

ampair

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Quote:
It's basically an electrostatic. What is the center diapragm charged to in the prototype and what sort of voltages swing on the electrodes (stators)?


if you haven't found out for yourself by now:
according to the paper (http://arxiv.org/abs/1303.2391), they use 100v for biasing and up to 10v peak amplitude (using a function generator).
and they were even able to power it from a standard laptop headphone jack. try that with nowadays' commercial electrostats :wink:
 
Sep 4, 2013 at 8:17 PM Post #7 of 9

goodvibes

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if you haven't found out for yourself by now:
according to the paper (http://arxiv.org/abs/1303.2391), they use 100v for biasing and up to 10v peak amplitude (using a function generator).
and they were even able to power it from a standard laptop headphone jack. try that with nowadays' commercial electrostats :wink:

got this from that. We here describe an electrostatically driven, high-efficiency, mechanically vibrating graphenediaphragm based audio speaker so they agree with me. The efficiency is a great benefit but it still needs a bias source. Will be interesting to see how it develops. 
 
Sep 23, 2013 at 9:51 AM Post #8 of 9

AHorseNamedJeff

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okay, this is super cool. subbing.
 

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