Most loudspeakers work using a diaphragm that creates pressure waves in air by mechanically vibrating. “For human audibility, an ideal speaker or earphone should generate a constant sound pressure level from 20 Hz to 20 kHz, i.e. it should have a flat frequency response,” say Qin Zhou and Alex Zettl who are both at the University of California, Berkeley.
Today, these guys unveil an earphone-sized speaker that more or less matches this requirement. What’s unusual about this speaker is that the diaphragm is made from a few layers of graphene, the carbon chicken-wire material that is revolutionizing everything from transistor design to particle physics experiments.
Five poems about the mind
Work reinvented: Tech will drive the office evolution
As organizations navigate a new world of hybrid work, tech innovation will be crucial for employee connection and collaboration.
I taught myself to lucid dream. You can too.
We still don’t know much about the experience of being aware that you’re dreaming—but a few researchers think it could help us find out more about how the brain works.
Is everything in the world a little bit conscious?
The idea that consciousness is widespread is attractive to many for intellectual and, perhaps, also emotional
reasons. But can it be tested? Surprisingly, perhaps it can.
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