GB2129597A - Improvements in and relating to clarinets - Google Patents

Abstract

Coning of particular dimensions is applied to the upper, and optionally lower, joint of wide-bore clarinets to improve intonation. Thus the bore diameter, which is to be in the range 15.1 to 15.3 mm., increases from below the speaker tube by at least 0.2 mm. at the upper tenon, where it is in the range 15.3 to 16.00 mm. Discontinuously increasing conicity at the lower end may also be employed. <IMAGE>

Description

SPECIFICATION Improvements in and relating to clarinets This invention relates to clarinets, in particular to Boehm system clarinets of wide bore which are well recognised as the "English" type of clarinet.

The bore of the clarinet is only truly cylindrical for from about two fifths to about two thirds of its length, the proportion varying with individual design, with gradual increase in diameter ("coning") invariably introduced at the bottom (or bell) end of the tube and not uncommonly, in instruments of foreign design, at the top end also. Even so, the clarinet behaves acoustically as a closed cylindrical tube, and thus overblows in twelfths. It is a well recognised fact that the twelfths between the fundamental (chalumeau) register and the first overblown (clarion) register tend to be narrow (i.e. a properly pitched chaiumeau register will overblow to a flat clarion register; or, conversely, a properly pitched clarion register will be accompanied by a sharp chalumeau).This narrowness applies to the twelfths based on the chalumeau notes written D down to G, particulariy the A, Bb and B natural.

The craft of instrument design is to improve intonation throughout the compass of the instrument whilst preserving, and hopefully improving, the quality of the sound to the satisfaction of the contemplated players and audiences. Bore diameter, both in its absolute value and in its variation, is a crucial factor in design.

I have now discovered modifications in the design of wide bore clarinets, which for the purposes of this specification are defined as clarinets the cylindrical portion of the bore of which has a diameter in the range 15.1 to 1 5.3 mm., which are uniquely effective in improving the intonation and timbre of such instruments.

According to the present invention a Boehm-system, wide-bore (as herein defined) clarinet is coned at the upper part of its top joint, the coning commencing no higher than the speaker tube and extending to the top of the upper tenon there providing a bore of 1 5.3 to 16.00 mm. which bore is at least 0.2 mm. greater than that of the cylindrical portion of the joint. The coning may commence lower in the joint than the speaker tube, but not lower than the thumb hole.

Practical considerations obviously favour straight-sided coning. However the effect of this coning, which is a general improvement in intonation, and particularly the curing of the narrowness of the twelfths based on chalumeau D to G aforesaid, is maximised by a coning in which the rate of increase of bore diameter progressively decreases from commencement of coning to upper tenon of top joint.

In a preferred embodiment of the invention the above-described coning of the top joint of the instrument is accompanied by a modification of the manner in which the bottom joint is coned. According to this embodiment the coning of the lower-part of the bottom joint of the instrument commences no lower than the lower extremity of the F#/C# tone hole, provides at the bottom of the lower tenon a bore of 21 to 23 mm., and comprises from 3 to 10 discontinuous conical sections the individual divergency of which progressively increases with proximity to the bell; this in contrast to the hitherto conventional continuously curved profile of the coning of this part of the instrument. Again, practical considerations will favour individual conical sections which are straight-sided.This lower-joint coning should commence no higher than the lower extremity of the G#/D# tone hole, and preferably includes 6 or 7 discontinuous conical sections.

Dispensing with reliance in manufacture on a single curved reamer (notoriously susceptible to uneven blunting, putting dimensional reproducibility at risk) for bottom cone formation is clearly beneficial. However the use of a succession of conical reamers to provide a stepped bottom cone according to this embodiment lies not only in the greater ease with which dimensional consistency is preserved from instrument to instrument but also in the flexibility afforded to the manufacturer in selecting bottom cone profile, which can be varied by alteration of the number of sections of which the bottom cone is made up and by alteration of the divergency of individual sections.Since bottom cone profile influences timbre, custom manufacture to suit individual players, notabiy those of sufficient expertise to experience concern with the narrow-twelfths phenomenon above referred to, becomes relatively easily achievable.

Although in describing the invention it has been convenient to refer to the top and bottom joints which the vast majority of clarinets possess, the invention obviously also applies to those instruments in which those joints are unitary. Moreover, since the invention embraces a family of instruments of varying size, axial dimensions have been stated in terms of tone-hole locations rather than in distances: thus the F#/C# tone hole is that which emits the written note F in the chalumean register and the written note C&num; in the first overblown register, and the G#/D# tone hole is that which emits the written note G# in the chalu mean register and the written note D# in the first overblown register.

An example of the invention will now be described, by way of illustration, with reference to the accompanying drawings, in which: Figure 1 is a section through the top joint of a commercially available Boehm system Bb clarinet which has been modified by coning in accordance with the invention; and Figure 2 is a section through the bottom joint of that same instrument, to which joint has been applied stepped coning in accordance with the preferred embodiment of the invention.

Both Figures are greatly distorted in scale in order clearly to portray the variations of bore diameter in which the invention is rooted.

Referring to Fig. 1, the top joint 1 terminates in a lower tenon 2 and an upper tenon 3. The diameter of the cylindrical portion of the bore, which extends from lower tenon to between thumb hole and speaker tube, is 15.2mm. Reaming of the bore, commencing at a point, 4, 80mm. from the top end of the top tenon, evenly increases the bore diameter from 15.2mm at 4 to 15.55mm at the top end of the top tenon.

Referring to Fig. 2, bottom joint 5 terminates at its upper end in a socket 6 and at its lower end in a tenon 7. Socket 6 is designed to receive upper joint tenon 2 and preserve well into the lower joint the basic 15.2mm diameter of the cylindrical portion of the instrument.

Stepped coning commences at the lower extremity of the tonehole for third finger right hand, 100mm. from the bottom extremity of tenon 7. The stepped coning commences at point 8 and proceeds in seven stages, the boundary between these stages being identified by reference numerals 9, 10, 11, 12, 1 3 and 14. The initial diameter of the bore in each stage is set out in the following table, as is the distance of each initial boundary from the end of the lower tenon.

Initial Distance from Section Bore end of tenon 8-9 15.20 100mm 9-10 15.56 77.5mm 10-11 16.00 63mm 11-12 16.78 47.25mm 12-13 17.88 32.75mm 13-14 19.26 18.75mm 14-end of tenon 20.40 10.75mm The bore diameter at the end of the tenon (15) was 22.1 mm.

Ali seven of these sections are strictly conical.

The instrument employed in the example was neither new nor expensive, and required prior reaming to increase the diameter of the cylindrical portion of its bore to 15.2mm.

Following application to it of the conings described in the Example the previously referred-to narrow twelfths had been, by even the most demanding standards, satisfactorily eliminated. Unlike the unpromising starting material, moreover, it manifested throughout its compass a tone quality of the kind sought by leading British players.

Claims (7)

1. A Boehm-system, wide-bore (as herein defined) clarinet having coning at the upper part of its top joint, the coning commencing no higher than the speaker tube and extending to the top of the upper tenon there providing a bore of 1 5.3 to 16.00 mm. which bore is at least 0.2 mm. greater than that of the cylindrical portion of the joint.

2. A clarinet according to claim 1 wherein said coning commences no lower than the thumb hole.

3. A clarinet according to claim 1 or claim 2 wherein the coning is straight-sided.

4. A clarinet according to claim 1 or claim 2 wherein the rate of increase of bore diameter progressively decreases from commencement of coning to upper tenon of top joint.

5. A clarinet according to any of claims 1 to 4 having further coning at the lower part of its bottom joint which further coning commences no lower than the lower extremity of the F/C4t tone hole, provides at the bottom of the lower tenon a bore of 21 to 23 mm.

and comprises from 3 to 10 discontinuous conical sections the individual divergency of which progressively increases toward the tenon.

6. A clarinet according to claim 5 in which said individual conical sections are straight-sided.

7. A clarinet according to claim 5 or claim 6 in which said further coning commences no higher than the lower extremity of the G#/D# tone hole.