l> Eight-foot Pitch

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 An organ pipe, or a harpsichord string, designated as eight-foot pitch is sounded at standard, ordinary pitch.[1] For example, the A above middle C in eight-foot pitch would be sounded at 440 Hz (or at some similar value, depending on how concert pitch was set at the time and place the organ or harpsichord was made).Contents1 Similar terms 2 Choice of length 3 See also 4 ReferencesSimilar terms Eight-foot pitch may be contrasted with four-foot pitch (one octave above the standard), two-foot pitch (two octaves above the standard), and sixteen-foot pitch (one octave below the standard).[2] The latter three pitches were often sounded (by extra pipes or strings) along with an eight-foot pitch pipe or string, as a way of enriching the tonal quality. The numbers just mentioned largely exhaust the possibilities for harpsichords; in organs a far greater variety is possible; see Organ stop. These lengths can all be obtained by successive doubling because, all else being equal, a pipe or string that is double the length of another will vibrate at a pitch one octave lower. Choice of length The particular length "eight feet" is based on the approximate length of an organ pipe sounding the pitch two octaves below middle C, the bottom note on an organ keyboard.[1] This may be calculated as follows. If a pipe is open at both ends, as is true of most organ pipes, its fundamental frequency f can be calculated (approximately) as follows: f = v 2 l displaystyle f= frac v 2l ,wheref = fundamental frequency v = the speed of sound l = the length of the pipeIf v is assumed to be 343 m/s (the speed of sound at sea level, with temperature of 20°C, and the pipe length l is assumed to be eight feet (2.44 m), then the formula yields the value of 70.4 hertz (Hz; cycles per second). This is not far from the pitch of the C two octaves below 440 Hz, which (when concert pitch is set at A = 440 Hz) is 65.4 Hz. The discrepancy may be related to various factors, including effects of pipe diameter, the historical differing definitions of the length of the foot, and variations in tuning prior to the setting of A = 440 Hz as the standard pitch in the 20th century. See alsoPipe organ Organ stop Harpsichord Acoustic resonanceReferences^ a b Hubbard, Frank (1965). Three Centuries of Harpsichord Harpsichord Making. Cambridge, MA: Harvard University Press. p. 354. ISBN 0-674-88845-6.  ^ Hubbard (1965: 355, 361)v t ePipe organs (list)ConstructionBuilders Console Eight-foot pitch Manual PedalsCrescendo pedal Expression pedal Pedal keyboardTremulant Tuning Swell boxPipesEn chamade FlueScalingReed Tibia Tibia ClausaStopsBombarde Bourdon Combination actionElectro-pneumatic Stop Tracker Tubular-pneumaticCornet Gedackt List Mixture Ophicleide Plein-jeu Registration Trompette militaire Voix céleste Vox humana ZimbelsternBarrel Crawl Fairground French German Historical Society Portative Positive Repertoire S

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