New Headphones Generate Sound With Carbon Nanotubes 102
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."
Re:Yes, but... (Score:5, Interesting)
It depends. Sound quality doesn't scale, generally, which is why standard speaker systems have vast arrays of speakers that operate over very narrow ranges. The sound quality using cones and magnets has gone as far as it can, short of moving to superconducting electromagnets.
There were some speakers demo'd on Tomorrow's World, way back when, which consisted of an electrode in a spherical wire mesh. The spark, pulsed at the right frequency, could generate sound. It was extremely high quality, far far higher than the Tesla Coil speakers you see on YouTube. But nothing ever came of the idea. Still not entirely sure why, but I suspect large amounts of ozone and the power you'd need to cross the gap they were using would make such a device uneconomic.
The nanotube idea is interesting, but I have a real concern that technology these days isn't about quality but quantity. Notice how the summary emphasizes the production of the system, but also observe how DVD lifespans are pathetic, hard drives have much shorter MTBF than earlier generations, MP3s largely replaced lossless codecs, digital cameras have a fraction of the effective pixel count of film, etc. Nobody wants high-end. They want crap that's tolerable and affordable. (Which also explains why Windows is a "success" and Linux has never made it to the desktop -- yet is the only serious OS in the few luxury/demanding markets left.)
It could be that nanotubes will prove to be capable of high-end sound, REAL hi-fi sound, but let's face facts. Even if it was, even given that the technology exists for 11.1 sound with an upper operating limit of 384 KHz at 24 bits, when was the last time you saw a CD with music recorded at that level? People want more tracks per piece of physical medium and would probably settle for 16 KHz at 16 bits resolution if it gave them a few more bonus tracks. There are audiophiles out there. I know. I'm one of them. Although, sometimes I think I'm the only one left. That depresses me, but you have to wonder. Purported audiophiles who can't tell what gives good sound and what doesn't clearly aren't audiophiles at all, they're blingophiles.
Re:Yes, but... (Score:4, Interesting)
You might be thinking of plasma tweeters. Back in the late 70s/early 80s. 10K1980$ a pair. Just tweets.
They had a gas flame that was made to generate sound with an electric field. Note: Typical electrostatics already have membranes that weigh less then the air they're moving.
Your dog _might_ be able to distinguish between plasma and normal electrostatics. Not that electrostatics are exactly cheap or small.
Re:Yes, but... (Score:5, Interesting)
I'm willing to bet they have very similar performance to Electrostatic speakers. Very low distortion, acting like a dipole radiator so you have to spend a lot of time positioning them to get them to sound right, very good dampening due to low driver weight. I'd suspect these things have near perfect dampening since all they're moving is a magnetic field and air.
There are a lot of downsides though, and I think they'd all apply here as well. Most notably, terrible bass response. And the number 1 problem in sound reproduction is and has always been bass. This is basically yet another new and inovative way to reproduce high frequencies. We have hundreds... yay...
http://en.wikipedia.org/wiki/Electrostatic_loudspeaker#Disadvantages [wikipedia.org]