Practically all the existing dynamics work on the same principle: the electric signal generates oscillations of the coil in the field of a permanent magnet, it drives the diffuser, and this, in turn, creates air vibrations and sound waves of the required frequency. But in the future, everything can change, because scientists from the British University of Exeter have created a fundamentally new type of dynamics from graphene, which does not need any mechanical vibration.
The principle of the new dynamics is based on a change in the temperature of graphene, the changes of which lead to the appearance of sound. Previously, graphene has already been used to create speakers, but in the past it was made from diffusers, which led to an increase in the efficiency of the device. From the new dynamics, all the moving parts disappeared, which allowed to reduce its size and increase its effectiveness. The speaker is made in the form factor of a microprocessor the size of a thumbnail. Inside the processor case, in addition to the speaker itself, the amplifier and even the graphic equalizer are hidden.
The thermoacoustic principle of operation allows you to convert the temperature into sound or vice versa – to convert sound vibrations into heat. This effect was first described at the end of the XIX century by the scientist Lord Rayleigh. In the middle of the twentieth century, interest in the interrelation between sound and heat greatly increased, since it was necessary to study the instability in combustion chambers with huge temperature differences. To date, there are thermoacoustic engines and even thermoacoustic refrigerators. But thermoacoustic speakers, and even from graphene, so far no one has created.
Graphene is an excellent conductor, therefore, by passing electrical impulses through it, you can quickly heat up and cool it. The grafen membrane expands and contracts, which affects the ambient air and generates sound waves. How good is the sound obtained in this way? The team of researchers claims that the graphene thermoacoustic speaker allows to get a “rich sound palette”, depending on how and where it is supplied with electricity. Heating and cooling cycles allow you to create multiple audio frequencies at the same time, while mixing them together, amplifying and tuning their sound. Scientists even managed to obtain ultrasound.
The results of research by British scientists were published in the journalScientific Reports.
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