Abstract:
For each register of the instrument, the device comprises at least one  auiary tube branched in the vicinity of the head of the instrument and a manual control mechanism making it possible to open or close the auxiliary tube at its first end in contact with the instrument or at its second end turned towards the outside. 
     This device more particularly applies to flute mouthpiece instruments or reed instruments, such as clarinets, saxophones, oboes and bassoons.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to devices for obtaining quarter-tones and other micro-intervals on wind instruments with lateral holes and more particularly on flute mouthpiece instruments, or reed instruments such as clarinets, saxophones, oboes and bassoons. 
     At present, for playing quarter-tones, the instrumentalist has to learn the same number of new fingerings as for normal playing and in addition all quarter-tone intervals cannot be obtained on all instruments. Moreover the solution consisting of doubling the number of keys is made impossible due to prohibitive costs and handling difficulties. 
     On certain traditional instruments, such as certain Hungarian bagpipes and reed pipes, it is known to translate the scale by a half-tone on an octave by using a hole made in the instrument wall which, when open, raises all the notes by a half-tone. This method, on which information is given hereinafter, is described in the article by A. BAINES, entitled BAGPIPES, Oxford University Press, 1973. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to obviate the aforementioned difficulties by supplying devices making it possible to translate the complete scale of an instrument, particularly a quarter-tone, in a simple manner and whilst eliminating any complicated fingering. 
     According to the present invention, a device comprises at least one auxiliary tube branched in the vicinity of the head of the instrument and a manual control mechanism comprising means to selectively close the auxiliary tube at its first end in contact with the instrument and to selectively open its second end turned towards the outside. 
     In the case of a flute, use is made of two auxiliary tubes branched in the vicinity of the head of the flute. 
     In the case of a transverse or cross flute, each of the two auxiliary tubes is mounted between the mouthpiece and the trill clef, for the first register its section S and its height h being such that S/h is between 0.2 and 0.7 mm with h between 30 and 120 mm, which gives for its diameter a value d between 2.7 and 9.9 mm. For the second register, its section S and height h are such that S/h is between 1 and 2.5 mm with h between 10 and 40 mm, which gives for its diameter d a value between 3.5 and 11.3 mm. 
     The device for a clarinet comprises at least one auxiliary mounted on the cylinder, mouthpiece or upper part of the body and a mechanism making it possible to close the tube or tubes, at least at one or other of their ends. 
     In the particular example of a B-flat clarinet, the device comprises an auxiliary tube corresponding to the first register mounted on the cylinder or on the upper part of the upper body and whose volume is between 2 and 5 cm 3  and an auxiliary tube corresponding to the second register, this being mounted on the cylinder, mouthpiece or upper body and whose volume is between 1 and 4 cm 3 . A manual control mechanism makes it possible to close the tube at at least one of its two ends and optionally an intermediate position between these two ends. 
     In the case of the saxophone and particularly the alto saxophone, the device comprises an auxiliary tube for the first register mounted on the bend, its section and height being such that S/h is between 0.08 and 0.3 mm with h between 10 and 250 mm, which for its diameter d gives a value between 1.4 and 6.2 mm. The device also comprises a first tube corresponding to the second register and which is mounted on the first half of the bend adjacent to the opening, its section and height being such that S/h is between 0.15 and 0.5 mm and its height is between 10 and 50 mm, so that for its diameter a value d between 1.4 and 5.6 mm is obtained, as well as a second tube for the second register which is mounted on the second half of the bend or on the top of the body, its section and height being such that S/h is between 0.7 and 2.6 mm with h between 5 and 20 mm, so that for its diameter a value between 2.1 and 8.1 mm is obtained. 
     Certain definitions and results of experiments will now be given making it possible to justify the choice of dimensions for the devices. 
     1. Definitions of the Intervals and Registers 
     For a given instrument, the calculation of the dimensions of the device is dependent on the considered register and the adopted micro-interval. The latter is defined by a relative increase of frequency A or a relative decrease of frequency D. The following table gives the values A and D for the main intervals: 
     
         ______________________________________Interval        A       D______________________________________1/8             0.0145  0.01431/4             0.0253  0.02851/3             0.0393  0.03781/2             0.0595  0.05612/3             0.0801   0.074131               0.1225  0.1091______________________________________ 
    
     for an interval of one nth of a tone then ##EQU1## To the nth register of such an instrument corresponds a frequency interval between f min  (low-pitched) and f max  (high-pitched). For the main instruments, the notes to which these intervals correspond are as follows: 
     
         ______________________________________Instrument First register second register______________________________________Transverse flute      Low C to medium C♯                     Medium D to high C♯Oboe       Low B to medium C♯                     Medium D to high C♯Saxophone  Low B to medium C♯                     Medium D to high F♯Bassoon    Low B to medium F                     Medium F.sub.11 to high FClarinet   Low E to medium B                     Medium B to high C______________________________________ 
    
     For the saxophone and clarinet, which are transposing instruments, the notes indicated are the notes written on the score and not the notes which are heard. For the instruments of the same non-transposing group such as the flute, oboe, bassoon, it is merely necessary to translate the notes given here. 
     2. Octaving Instruments: Open Tube Systems 
     (a) Principle 
     In order to obtain a relative increase of the frequency A of the nth register of the instrument [f min , f max  ], the open tube must be spaced from the exciter or instigator by approximately ##EQU2## in which c is the speed of sound (c=345 cm/s at 22° C.). 
     This tube of height h and section S must be such that its acoustic &#34;inertia&#34; (cf below) is: ##EQU3## in which S is the internal section of the instrument at the location of the open tube. The density of air is estimated as being equal to 1 for simplification reasons. 
     The two above relations must be observed to within 50%. What is stated hereinafter defines the notions of inertia and distance from the exciting system. 
     (b) Definition of the inertia 
     The quatity S/h with respect to the flute is a simplification of the quantity: ##EQU4## which is the inverse of the acoustic inertia L, representing the inertia of the air in the tube (cf BERANEK, ACOUSTICS, 1954, P. 131, MCGRAW HILL, NEW YORK). 
     Results are given hereinafter of experiments carried out more particularly on the transverse flute, a B-flat clarinet and an alto saxophone. 
     Flute: 1st register 
     The auxiliary tube is mounted on the head of the flute, its dimensions being such that S/h is between 0.2 and 0.7 mm with h between 30 and 110 mm and e.g. for: 
     
         ______________________________________h = 30 mm       d is between 2.7 and 5.2 mm,h = 110 mm      d is between 5.3 and 9.9 mm.______________________________________ 
    
     flute: 2nd register 
     The auxiliary tube is mounted on the head of the flute, its dimensions being such that S/h is between 1 and 2.5 mm with h between 10 and 40 mm, e.g. for: 
     
         ______________________________________h = 10 mm      d is between 3.5 and 5.7 mm,h = 40 mm      d is between 7.1 and 11.3 mm.______________________________________ 
    
     Clarinet: 1st register 
     The auxiliary tube is mounted on the cylinder or the top of the upper body and its volume is between 2 and 5 cm 
     Clarinet: 2nd register 
     The auxiliary tube is mounted on the cylinder, the mouthpiece or upper body and its volume is between 1 and 4 cm 3 . 
     Alto saxophone: 1st register 
     The auxiliary tube is mounted on the mouthpiece, its dimensions being such that S/h is between 0.08 and 0.3 mm with h between 10 and 250 mm, e.g. for: 
     
         ______________________________________h = 20 mm       d is between 1.4 and 2.8 mm,h = 100 mm      d is between 3.2 and 6.2 mm.______________________________________ 
    
     Alto saxophone: 2nd register 
     This first auxiliary tube is mounted on the first half of the bend. The ratio S/h is between 0.15 and 0.5 mm with h 5 and 100 mm, e.g. for: 
     
         ______________________________________h = 10 mm      d is between 1.4 and 2.5 mm,h = 50 mm      d is between 3.1 and 5.6 mm.______________________________________ 
    
     The second auxiliary tube is mounted on the second half of the bend or on the top of the body. The ratio S/h is between 0.7 and 2.6 mm with h between 5 and 30 mm, e.g. for: 
     
         ______________________________________h = 5 mm       d is between 2.1 and 4.1 mm,h = 20 mm      d is between 4.2 and 8. mm.______________________________________ 
    
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described in greater detail hereinafter relative to non-limitative embodiments and the attached drawings, wherein show: 
     FIGS. 1 and 2, respectively side and rear views of a known Hungarian bagpipe element. 
     FIGS. 3, 4, 5, respectively a flute, clarinet and a saxophone. 
     FIG. 6, diagrammatically a flute and opening and closing mechanisms for the auxiliary tubes. 
     FIG. 7, diagrammatically a clarinet equipped with two auxiliary tubes. 
     FIG. 8, diagrammatically a saxophone and an auxiliary tube. 
     FIGS. 9a and 9b, pitch variation curves respectively for the first and second registers of the transverse flute. 
     FIGS. 10a and 10b, the pitch variation curves respectively for the first and second registers of the B-flat clarinet. 
     FIGS. 11a and 11b, the pitch variation curves respectively for the first and second registers of the alto saxophone. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The Hungarian bagpipe element normally called a chanter shown in FIGS. 1 and 2 is a pipe which gives the melody and which can therefore be likened to a oboe. In its upper part is provided a very small hole 1 made through a relatively thick wall. When this hole is open, it increases the pitch of most notes by approximately a semitone and is often used for giving the effect of a transitory vibrato on these notes. 
     The principle of using this hole is not very well known and it is only used on relatively high-pitched instruments in a rather approximate manner. It cannot be applied either to low-pitched registers or to instruments having thin walls, such as BOEHM system flutes and saxophones. It can also not be applied to the clarinet. 
     In the case of the flute shown in FIG. 3, it is possible to see the head 3 and its mouthpiece or opening 5, the body 7 and its trill clef 9 and C clef 10. The two auxiliary tubes corresponding to the first and second registers of this instrument are fitted between mouthpiece 5 and the trill clef 9. 
     In the case of the clarinet shown in FIG. 4, it is possible to see the mouthpiece 11, cylinder 13, upper body 15, lower body 17 and the bell or opened-out region 19. The auxiliary tube corresponding to the first register is fitted between cylinder 13 and upper body 15, whilst the auxiliary tube corresponding to the second register is fitted on cylinder 13, mouthpiece 11 or upper body 15. 
     In the case of the saxophone shown in FIG. 5, it is possible to see the mouthpiece 21, bend 23 and body 25. The auxiliary tube corresponding to the first register is mounted on bend 23, whereas the first tube of the second register is mounted on the first half of bend 23 adjacent to the mouthpiece and the second tube of the second register is mounted on the second half of the bend 23 or on the top of body 25. 
     FIG. 6 shows three embodiments of the device according to the invention. 
     According to a first embodiment, the auxiliary tube 20 is mounted perpendicular to the axis of the flute. A valve 22 comprises means to selectively block the tube 20 adjacent the instrument and to selectively open its other end. The valve 22 moves within the tube between a position where it is fully inserted to block the opening 24 common to the flute and the tube and a second position where it is located entirely outside the tube and so opens the tube. 
     According to a second embodiment, the auxiliary tube 30 is mounted parallel to the flute axis. Valve 32 moves between a position where it is entirely inserted blocking the opening 34 common to the flute and the tube and a position where it is completely outside the tube, so that the latter is completely open. 
     According to a third embodiment, the auxiliary tube 40 is mounted parallel to the flute axis, but is equipped with a valve 42 moving parallel to the flute axis between a position where it is completely inserted so as to block both the opening 44 common to the flute and the tube and the opening 46 for the removal of the tube and a position where it is in contact with the lower wall 48 of the tube, opening 46 being opened. 
     It is pointed out that in these three exemplified embodiments, the valve moves between a position of closing the opening common to the flute and tube, in which case a standard flute is involved, and a position where the tube is completely open both towards the flute and towards the outside, in which case the flute has notes raised by a quarter-tone. This property has been experimentally proved and can clearly be gathered from examining the curves in FIGS. 9a and 9b respectively corresponding to the first and second registers. It is pointed out that all the curves shown in continuous lines relate to standard instruments, whereas those in dotted line form relate to instruments equipped with devices according to the invention. 
     The clarinet shown in FIG. 7 is equipped with two auxiliary tubes, namely a first tube 50 corresponding to the first register mounted on the upper part of upper body 15 and a second tube 52 corresponding to the second register mounted on mouthpiece 11. Each valve P1, P2 can move between a position closing opening 54, 55 where it blocks the auxiliary tube 50, 52 and a position where it strikes against the bottom 58, 60 of the tube and where a certain tube volume V is linked with the air column of the clarinet. 
     It is pointed out that when openings 54, 55 are blocked by valves P1, P2 respectively, a normal clarinet is involved. However, when the valves P1, P2 strike against the walls 58, 60 of the tubes, the clarinet air column is increased by two volumes V and the two registers are lowered by a quarter-tone, as can be gathered from FIGS. 10a and 10b, where the curves respectively relate to the first and second registers. 
     In the case of a saxophone and as stated herein before, the device according to the invention comprises three tubes, one of them being diagrammatically shown in FIG. 8. It can be seen that tube 70 is mounted perpendicular to the saxophone axis. This tube is internally traversed by a valve 72, which functions in the same way as the flute valves between a position where opening 74 is blocked and a position where the valve is completely outside the tube. When the three saxophone tubes are unblocked, the two registers are raised by a quarter-tone, as can be gathered from the curves 11a and 11b. 
     It is obvious that the above embodiments have only been given in an illustrative manner and that numerous modifications and variations can be made thereto without passing beyond the scope of the invention. In particular, it is obvious that the tubes could be given widely varying shapes according to the requirements of technology and that the choice of the valve control mechanisms is a function of the instrument involved.