The Revised Scale 2012.   (RS 2012)

A = 440/442. Updated January 2014

This is based on an octave scale length from C1- C2 of 324.1mm.  This is adequate for playing at 440-442cps.

Instructions:- To check a flute or to mark up a stick:- measure your tone hole diameters to see if they are close to, or the same as those in the first column.  Read the figures in the column which describes your flute, A, B or C. The large C# (B/C# trill) has also been shown. On a C foot, the end of the flute is C natural and on a B foot, the end of the flute is B or 0.00. The key cup rise should be 4.5mm in the foot and 4.0 in the right hand; 3.5mm in the left. This is larger than customary but important for both pitch and tone.

Since the calculation of this scale, we have corrected some notes slightly after performing trials. These notes are now incorporated into the figures set out below. 

The Figures

                                                           A                                 B                                            C

                        Tone hole               C Foot                          C Foot                                  B foot

Tone holes      Diameters          (Closed hole)                 Open cups)                             (Open cups)

Low B              15.6                          ---                                  ---                                       0.00

---------------------------------------------------------------------------------------------------------------------------------

Low C              15.6                      0.00                                   0.00                                  45.5

C#                                                  43.35                                43.35                                 81.85      

D                                                   77.7                                   77.7                                  116.2

Eb                                                 110.1                                 110.1                                148.6

............................................................................................................................................................................

E                        14.2                    141.8                                  140.1                                178.6

F                                                   169.3                                  168.05                              206.55

F#                                                 197.7                                  196.45                              234.95

G                                                  224.3                                   224.3                                262.8  

............................................................................................................................................................................

G#                      13.5                   248.2  (if 12.8 then 248.65)        248.2  (if 12.8, then248.65)      286.7  (If 12.8: 287.15)

A                                                  270.6                                   269. 45                             307.95

Bb                                                293.15                                 292.15                              330.75

B                                                  314.0                                   314.0                                352.5

C                                                  333.15   (if 12.8, then 333.55)     333.15  (if 12.8, then 33.6)     371.65 (if 12.8, then 372.05)      

C# large trill                                  352.4   (if 12.8  then 352.85)       352.4   (if 12.8, then 352.85)     390.9  (12.8: 391.35)

........................................................................................................................................................................

C#  normal          6.7                 364.3                                       364.3                               402.8

              (This hole position has been revised (sharpened  by 0.5mm) after a lot of testing and experiments, to address the slightly flat octave. The tone hole should also be undercut all round, but the diameter of the top of the hole should remain at 6.7mm). This tone hole should be deeper than the others by 0.5mm and the key cup opened to 3.5mm above the tone hole)  This is important.

........................................................................................................................................................................

D (trill)           7.5                       382.8                                         382.8                                421.3

D#                 7.5                       398.7                                         398.7                                437.2

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The 'End Correction' (the distance from the end of the flute to the centre of the low C# hole) = 7mm. This figure has already been added to the final figures. The open hole corrections (Eldred Spell, March 2011)  E: 1.7mm; F: 1.25mm; F#: 1.25mm; A: 1.12mm; A#: 1.1mm.

To check your flute against the figures above: Use large size Vernier calipers and sharpen, by filing, the fixed inside edge so as to make a sharp edge for an accurate reading against the inside face of each tone hole. Measure the diameter of each tone hole north to south and east to west (this is to check if both are identical). If the tone hole diameters differ from those given above, a correction should be made, though most flutes will correspond. (A tiny difference is not important). Now measure each tone hole from the end of the foot to the inside (south) edge of each hole. Add the radius (half the diameter) to this figure. This gives the distance from the end of the foot to the centre of each hole. Compare with the figures above.

                                                                 William Bennett, Eldred Spell and Trevor Wye.   January  2014


                                                           A                                 B                                            C

                        Tone hole               C Foot                          C Foot                                  B foot

Tone holes      Diameters          (Closed hole)                 Open cups)                             (Open cups)

Low B              15.6                          ---                                  ---                                       0.00

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Low C              15.6                      0.00                                   0.00                                  45.5

C#                                                  43.35                                43.35                                 81.85      

D                                                   77.7                                  77.7                                  116.2

Eb                                                 110.1                                 110.1                                148.6

............................................................................................................................................................................

E                        14.2                    141.8                                 140.1                                178.6

F                                                   169.3                                  168.05                              206.55

F#                                                 197.7                                  196.45                              234.95

G                                                  224.3                                   224.3                                262.8  

............................................................................................................................................................................

G#                      13.5                   248.2  (if 12.8 then 248.65)          248.2  (if 12.8, then248.65)        286.7  (If 12.8: 287.15)

A                                                  270.6                                   269. 45                              307.95

Bb                                                293.15                                 292.15                                330.75

B                                                  314.0                                   314.0                                  352.5

C                                                  333.15   (if 12.8, then 333.55)        333.15  (if 12.8, then 33.6)   371.65 (if 12.8, then 372.05)      

C# large trill                        352.4   (if 12.8  then 352.85)                  352.4   (if 12.8, then 352.85)          390.9  (12.8: 391.35)

........................................................................................................................................................................

C#  normal          6.7                 364.3                                             364.3                                      402.8

              (This hole position has  been revised (sharpened  by 0.5mm) after a lot of testing and experiments, to address the slightly flat octave. The tone hole should also be undercut all round, but the diameter of the top of the hole should remain at 6.7mm)

This tone hole should be deeper than the others by 0.5mm and the key opened to 3.5mm above the tone hole)  This is important.

........................................................................................................................................................................

D (trill)           7.5                       382.8                                         382.8                                421.3

D#                  7.5                        398.7                                         398.7                                437.2

------------------------------------------------------------------------------------------------------------------

The 'End Correction' (the distance from the end of the flute to the centre of the low C# hole) = 7mm. This figure has already been added to the final figures.

The open hole corrections (Eldred Spell, March 2011)  E: 1.7mm; F: 1.25mm; F#: 1.25mm; A: 1.12mm; A#: 1.1mm.

To check your flute against the figures above: Use large size Vernier calipers and sharpen, by filing, the fixed inside edge so as to make a sharp edge for an accurate reading against the inside face of each tone hole. Measure the diameter of each tone hole north to south and east to west (this is to check if both are identical). If the tone hole diameters differ from those given above, a correction should be made, though most flutes will correspond. (A tiny difference is not important). Now measure each tone hole from the end of the foot to the inside (south) edge of each hole. Add the radius (half the diameter) to this figure. This gives the distance from the end of the foot to the centre of each hole. Compare with the figures above.

                  William Bennett, Eldred Spell and Trevor Wye.   January  2014

                                                                  




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