No hard science in this article but interesting nonetheless.
http://www.noiseaddicts.com/2008/11/worlds-thinnest-speakers-carbon-nanotube/
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World's Thinnest Speakers? Nano Technology and Carbon Nanotubes
Re: World's Thinnest Speakers? Nano Technology and Carbon Nanotubes
Here's the hard science:
http://pubs.acs.org/doi/full/10.1021/nl802750z
Here's the interesting bit:
"Despite the excellent acoustic performance of the CNT loudspeaker, it has a drawback. As shown in Figure 2d, the output frequency doubles that of the input. The human voice and music sound strange when a commercial bipolar audio amplifier is used to drive the CNT thin film loudspeaker. A simple solution is to add a direct current bias I0 to the alternating current for driving such CNT loudspeakers. To achieve this, we use a very simple single transistor amplifier to drive our CNT loudspeaker, which can reproduce the input sound wave signals faithfully. The schematic circuit is shown in Figure S2 of the Supporting Information. Note that the impedance of the CNT loudspeaker is pure resistance (see Supporting Information, Figure S1), and the design of the amplification circuit is much simpler than that for inductive voice-coil loudspeakers. Also the resistance can be tuned to any value to meet the requirement of driving circuits, simply by adjusting the position of the electrodes (e.g., the resistance of the loudspeaker shown in Figure 1c is 500 Ω, in Figure 1d it is 8 Ω).
With the self-made simple amplifier, the CNT thin film loudspeaker possesses all the functions of a voice-coil loudspeaker, as well as the merits of being magnet-free and without moving components. Besides these, there are some remarkable added values of the CNT thin film loudspeaker inherited from CNT materials."
http://pubs.acs.org/doi/full/10.1021/nl802750z
Here's the interesting bit:
"Despite the excellent acoustic performance of the CNT loudspeaker, it has a drawback. As shown in Figure 2d, the output frequency doubles that of the input. The human voice and music sound strange when a commercial bipolar audio amplifier is used to drive the CNT thin film loudspeaker. A simple solution is to add a direct current bias I0 to the alternating current for driving such CNT loudspeakers. To achieve this, we use a very simple single transistor amplifier to drive our CNT loudspeaker, which can reproduce the input sound wave signals faithfully. The schematic circuit is shown in Figure S2 of the Supporting Information. Note that the impedance of the CNT loudspeaker is pure resistance (see Supporting Information, Figure S1), and the design of the amplification circuit is much simpler than that for inductive voice-coil loudspeakers. Also the resistance can be tuned to any value to meet the requirement of driving circuits, simply by adjusting the position of the electrodes (e.g., the resistance of the loudspeaker shown in Figure 1c is 500 Ω, in Figure 1d it is 8 Ω).
With the self-made simple amplifier, the CNT thin film loudspeaker possesses all the functions of a voice-coil loudspeaker, as well as the merits of being magnet-free and without moving components. Besides these, there are some remarkable added values of the CNT thin film loudspeaker inherited from CNT materials."
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- Tomás Mulcahy
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Re: World's Thinnest Speakers? Nano Technology and Carbon Nanotubes
I seem to remember something like this on Tomorrow's World a number of years back. They had an example of the system mounted on the front of a computer monitor: totally transparent and, from what I remember, a very tinny sound. That video in their article isn't working on my internet connection (wonderful school filters) so I can't tell if it's any better. I doubt it'll be in competition with a proper set of studio monitors for a very long time though.
