Interesting article on "The Caribbean Steel Pan: Tuning and Mode Studies" by Uwe J. Hansen, Thomas D. Rossing, Ellie Mannette, and Kaethe George in the MRS (Materials Research Society) Bulletin, V. XX, No. 3, March 1995. There is a table showing the inharmonicity of a particular note on a particular pan, giving the following ratios of the partials to the fundamental. 1st partial (fundamental) 1 2nd 1.98 3 2.97 4 3.96 5 4.93 In other words, the partials fall below the pitches of a true harmonic series, the opposite of what we're used to in pianos. A sound pressure spectrum is also given, showing a fairly smooth decrease in energy as the partial series is ascended, rather like piano spectra. There is also appreciable "coupling" with other notes on the same pan, if they are tuned harmonically (as opposed to equal-tempered intervals, for instance). The authors note that there is lots of variation in the behavior of various pans since they are made of various grades and gauges of steel, with the heads usually of different material than the skirts, and neither made with matalurgically sophisticated nor highly controlled alloys. The heads (which start life as the bottoms of 55-gallon oil drums) are heat-treated over open flame at about 600 degrees F. After cooling, the tuning is done by hammering, peining and punching the shapes of the various segments. Typically three to eighteen notes are produced on one pan. The article gives a bibliography of only three other references, one unpublished, the other two in JASA, 82 (1987) p. S86. Hope this helps! - - Tom McNeil - - Vermont Piano Restorations
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