Scraper Flute is my name for a tube with ridges formed by grooves cut into the surface. The air column is set to vibrating by scraping over the surface of the tube with a metal rod. The resulting agitation of the tube wall excites the air within. The length of the tube determines the pitch. The tubes can be made of plastic or (following the lead of the late Darrell DeVore) of bamboo — different materials make different tone qualities. The version shown here is a flexibly mounted set of tubes forming a chromatic scale. I’ve also made scraper flutes with flute-like tone holes so that a scale can be produced while scraping a single tube.
In the audio clip, the scraper flutes are joined by several bird calls and miscellaneous percussion.