Whirly tube
The whirly tube, corrugaphone, or bloogle resonator, also sold as Free-Ka in the 1960s-1970s, is an experimental musical instrument which consists of a corrugated (ribbed) plastic tube or hose (hollow flexible cylinder), open at both ends and possibly wider at one end (bell), the thinner of which is rotated in a circle to play.
In spite of being an aerophone, it is usually included in the percussion section of "sound effects" instruments, such as chains, clappers, and thunder sheets.
"[4] Hopkin describes that with a corrugahorn, "with tubes of suitable length and diameters, the range extends well up the [harmonic] series, where the available tones are close together and you can, with practice, play quite melodically.
"[7] The timbre of the notes produced by the whirly tube are, "almost all fundamental," according to Fourier analysis (similar to sine waves).
Crawford in 1973, as follows, proposes that the air flowing through the corrugations should produce a sound similarly to a scraping instrument, such as a "reco-reco", in which a stick is scratched against a surface with regularly spaced grooves.
A unique aspect of this whistle is that the internal flow carries both the unstable vortex downstream and the returning feedback signal upstream.
[citation needed] An ensemble of whirlies produces astounding musical patterns of vibrant clear pitch, sometimes hauntingly beautiful, sometimes dramatic, sometimes soft, sometimes strong and robust, but at all times inspiring and thought provoking.A corrugated plastic tube whirling instrument became an instant, if short-lived, cultural phenomenon in late 1960s New York City under the name "Free-Ka", sold by street vendors, as captured by The New Yorker in 1970.
[13] It has been used by a number of artists including Peter Schickele, Frank Ticheli, Paul Simon, Macy Gray, Loch Lomond,[citation needed] and Yearbook Committee.
It has been employed in some of Peter Schickele's comic P. D. Q. Bach compositions such as the Erotica Variations: IV (1979),[15][16][17] Missa Hilarious (1975),[18] and Shepherd on the Rocks with a Twist (1967).
[21] The inventor is not known, though Bart Hopkin credits the late Frank Crawford of the UC Berkeley Department of Physics with, "developing the idea and researching the underlying acoustics,"[5] and in 1973 Crawford credits another professor with pointing out to him a toy which, "about a year or two ago...appeared in toy stores across the land," and gives the brand or trade names "Whirl-A-Sound", "Freeka", and "The Hummer"; the last being made by W. J. Seidler Co. of L.A., CA.
