Scientists from the VTT Technical Research Center of Finland and the Helsinki University of Technology have developed a loudspeaker system, which unlike ever before, uses tiny aluminum wires suspended like a bridge between two supports to create a wide range of thermoacoustic applications. We’ve seen the technique of thermoacoustics tamed by the Chinese researchers in their effort to create a loudspeaker from carbon nanotubes, but this Finnish process may just be a simplification of the technique.
Herein, the aluminum wire bridge that measure 200 micrometers long, 3 micrometers wide and just 30 nanometers thick is suspended just a few micrometers above a substrate. When a controlled voltage is passed through this aluminum wire bridge, slight vibrations are generated which create tiny sound waves. By adding direct current however, researchers managed to generate speech and music from the morphed loudspeaker.
In words of Clay Dillow of PopSci,
constructed several versions of the speaker, ranging from 6,000-wire arrays to some as large as 233,000 wires. The resulting speakers can generate high-pressure sound waves up to 100 decibels at a 8-cm ranges, and can reach frequencies up to 40,000 Hz, far beyond the human hearing range of 20-20,000 Hz.