• Scientists create film for windows that blocks noise and plays music


    They have been working on a window-mounted sheet of transparent film that plays music and blocks unwanted noise.

    Unlike regular speakers, which are set in motion by electromagnets, the A*Star contraption is piezoelectric - it moves in response to changes in electrical voltage.

    Made of a polymer strengthened with transparent lamination, its powers go beyond making music: it also cuts out unwanted noise, using the same principle as noise-cancelling headphones.

    Sound consists of waves that oscillate rapidly between low and high pressure.

    A signal processor measures these waves 50,000 times a second, analyses them automatically, and commands the speakers to produce similar waves but with one crucial difference.

    The high-pressure parts of the speaker's waves coincide with the low-pressure parts of the noise and vice versa, a process that does what it is called - destructive interference.

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