Watch the short film Rumor Macchina.
The "rumor macchina" is a machine which converts acoustic signals into energy. Done in the style of a documentary, the "inventor" of this machine is interviewed and accompanied during a conversion. He describes both his motivation and his vision for coming up with this ground-breaking achievement.
In his opinion, the "rumor macchina" would also in a way be a solution to the problem of noise in big cities, as this would no longer be seen as pollution but as a necessary alternative energy source.