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New Headphones Generate Sound With Carbon Nanotubes
MTorrice writes "A new type of headphone heats up carbon nanotubes to crank out tunes. The tiny speaker doesn't rely on moving parts and instead produces sound through the thermoacoustic effect. When an alternating current passes through the nanotubes, the material heats and cools the air around it; as the air warms, it expands, and as it cools, it contracts. This expansion and contraction creates sound waves. The new nanotube speaker could be manufactured at low cost in the same facilities used to make computer chips, the researchers say."
And it exists in the real world: "The Tsinghua researchers integrated these thermoacoustic chips into a pair of earbud headphones and connected them to a computer to play music from videos and sound files. They’ve used the headphones to play music for about a year without significant signs of wear, Yang says. According to him, this is the first thermoacoustic device to be integrated with commercial electronics and used to play music."
..what do they sound like?
Ultin I can buy replacement headphones using this technology on DealExtreme for $2 shipped, it's a novelty at best.
These ones go up to eleven.
FTA
Unfortunately, the devices struggled to dissipate the heat created while generating sounds,
Careful not to crank the music on your new nanopodz(tm) too loud, or you'll literally fry your eardrums...
OTOH, talk about a hot beat :o)
"I love animals! Some are cute, others are tasty, what's not to like?" - Betsy Schroeder, Jeopardy contestant
The researchers noted that "unfortunately" the nanotube speakers use much higher amounts of power to drive them.
Forget little dinky nano-tubes in your ears, a real man would put plasma arcs in their headphones. Like this:
http://www.youtube.com/watch?v=YyVTvtgm11o
When information is power, privacy is freedom.
I wasn't aware that our current headphones had any problems that would be addressed with nanotubes. We have small phones that fit in the ear, big phones that look stupid on peopel, and everything in between. In all my years of using earbuds, it's always the cord that fails. Not the buds themselves. Now if they can fix THAT problem, that'd be worth something.
Dynamic drivers, as are normally used in headphones and speakers, still have problems in that regard. We can build amps, DACs, and so on that are essentially better than our hearing. Their frequency response, noise level, and THD are so low that they are completely inaudible, you can swap them out in a blind test and nobody can tell.
Then you hit the playback device and that all goes to hell.
You are hard pressed to find something that is both economical and has a flat FR and low distortion. Ideally you want it flat to less than 1dB and THD under 1% at all volume levels, and even less could be useful (we don't have real good data on when things stop being audible, just that at those levels it is audible in almost all cases).
So, better technology could allow for better specs in this area. That is what we'd be after. To try and get drivers that are affordable, and are accurate to beyond the limits of hearing. We'd like to have an audio system that truly had no sound of its own, that reproduced whatever it was given perfectly, as far as our ears can tell.
You need Monster(tm) cables to go beyond 11 without sacrificing quality.
The Tsinghua researchers...
My first thought upon reading the summary was, "Which Tsinghua University"? In this case it's the one in Mainland China, but there's a fascinating backstory behind my initial confusion regarding the history of Tsinghua University.
Following the defeat of the Boxer Rebellion (1899 - 1901), the China was made to pay an enormous sum in reparations to the great powers -- Russia, Germany, France, Britain, Japan, and the US. While the American share of the reparations was relatively minor (about 7% of the total) it still represented an excessive amount. American Secretary of State John Hay -- serving in the administration of Teddy Roosevelt -- arranged for about a third of the funds to be used for to set up scholarships, as well as a new school in Beijing which served to prepare students for overseas study in the US. It was this institution that eventually became Tsinghua University, one of the most prestigious learning institutions in China.
There's more to the history however. Following the Chinese Civil War, the defeated Nationalists retreated to Taiwan. A large portion of the Tsinghua staff fled with them and founded a new Tsinghua University in Taiwan (or perhaps they merely re-located the original to Taiwan, depending on your point of view). This other Tsinghua went on to become one of the top Universities in Taiwan as well.