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The dulcet tones of helicopter rotors

Karlheinz Stockhausen's "Helicopter String Quartet" blends the sounds of instruments with the din of helicopter rotors.

Is the sound of helicopter rotors music to your ears? Then perhaps you would have enjoyed Sunday's performance of the "Helicopter String Quartet" by contemporary German composer Karlheinz Stockhausen.

Helicopter String Quartet CD
Cover of 'Helicopter String Quartet' CD

For the piece, a quartet of musicians play their instruments from inside four hovering helicopters also carrying pilots and sound technicians. The strings blend with the steady sounds of the rotors for the 30-minute piece, which is part of Stockhausen's opera Wednesday from Light.

Sunday's performance, the site Deutsche Welle reports, was put on by the city of Braunschweig, Germany, which currently holds the title "Germany's City of Science 2007."

The concert took place in a hangar. Once the helicopters hit 2,300 feet and appeared only as specks in the sky, the hangar doors closed and the audience watched the musicians on four large screens, according to Deutsche Welle.

While the piece has been performed sells a CD--we hadn't heard of it until now (it's not yet exactly as well known as Beethoven's "Moonlight Sonata" or Vivaldi's "The Four Seasons," after all). The composer has said he first conceived of "Helicopter String Quartet" in a dream.