Tubular bells with weights attached to nodes of fourth overtone for adjusting overtones to target frequency ratio

Abstract: Chimes or tubular bells generate sounds through vibrations of metallic tubes (2), and weight members (2c-2e) are attached to nodal points on each metallic tube where the nodes of the fourth overtone (f4) take place; the weight members (2c-2e) decease the frequencies of the third and fifth overtones (f3/f5) without an influence on the fourth overtone so as to regulate the first overtone, the fourth overtone and the third overtone to a target frequency ratio of 2 : 3 : 4.

Description: FIELD OF THE INVENTION This invention relates to chimes or tubular bells forming a part of an orchestra and, more particularly, to tubular bells for generating sounds with notes exactly tuned along a scale. DESCRIPTION OF THE RELATED ART Tubular bells include a plurality of metallic tubes. The plurality of metallic tubes are hung on a rack, and are arranged in such a manner as to sequentially generate notes of a scale. A player strikes the metallic tubes with mallets, and the vibrating metallic tubes generate beautiful sounds like a church bell. The metallic tubes are usually formed of brass. The vibrations on the metallic tube are like transverse vibrations generated on a bar with both free ends, and the vibrations on the respective metallic tubes have characteristic frequencies, respectively. The fundamental frequency f0 of each metallic tube is given by the follow equation. f0 = 1.133 pi L 2 (EK 2 / rho) Where L is the length of the metallic tube, E is the Young's modulus of the metallic tube in dyne/cm 2 , K is the coefficiency regarding the section shape and rho is the density of the material of the metallic tube. The coefficiency regarding the section shape K is expressed by equation 2. K 2 = (do 2 + di 2 )/ 16 where do is the outer diameter and di is the inner diameter. The third overtone f3 gives the note of the scale to the standard tubular bell, and the tubular bell is expected to form a frequency ratio between the third overtone f3, the fourth overtone f4 and the fifth overtone f5 as close to 2 : 3 : 4 as possible. Thus, the third to fifth overtones are important for the tubular bell; however, the fundamental tone, the first overtone and the second overtone are noise components. When a manufacturer designs the tubular bells, the tubular bells are adapted to have the third overtones f3 tuned to respective frequencies, and the tuning error is of the order of 1 to 2 cents. The unit "cent" means a logarithmic difference in frequency between two tones, and a semi-tone is equal to 100 cents. For the tuning work, the manufacturer forms metallic tubes slightly longer than these target lengths, and tunes the metallic tubes by cutting the original tubes. If the third overtone is still lower than the target frequency, the metallic tube is cut, again. On the other hand, if the third overtone becomes higher than the target frequency, the weight is added to the metallic tube at the end of the length. In this way, the manufacturer tunes the tubular bells. However, when the third overtones are respectively tuned to the target frequencies, the tuned tubular bells have respective fourth overtones and respective fifth overtones, and the fourth and fifth overtones are not tunable. For this reason, each of the fourth and fifth overtones is usually offset from the target frequencies by a third or a fourth of the semi-tones, and the prior art tubular bells tend to produce an impression of incorrect scale on the ear. Figure 1 illustrates the frequencies of the notes generated by the prior art tubular bells. The fundamental frequency is represented by "f0", and "f1" to "f6" stand for the first overtone to the sixth overtone. "Ce" represents the logarithmic frequency difference from the third overtone f3, and the unit is "cent". The rightmost column "f3/fr3" is assigned to an accuracy of the tuning work, and the accuracy is expressed on the basis of the frequency of the note A49 at 440 Hz. The frequencies were measured at 23 degrees in centigrade. Several overtones such as the first overtone and fifth overtone of C53 # were respectively expressed by sets of two different frequencies, and the two near different frequencies were causative of a beat. The note C52 had the third overtone f3 at 525.6 Hz. For the third overtone f3 was the standard on this chart, and the frequency difference was zero cent. However, the fourth overtone f4 was 775.8 Hz, and was spaced from the third overtone f3 by 674.1 cents. The target fourth overtone f4 was 702 cents, and the actual fourth overtone was deviated from the target value by -27.9 cents. The fifth overtone f5 was 1067.2 Hz, and was spaced from the third overtone f3 by 1226.2 cents. The target fifth overtone f5 was 1200 cents, and the actual fifth overtone f5 was offset from the target value by 26.2 cents. The other notes c53 # , D54, D55 # , E56, F57 and F58 # had the similar tendency. As described hereinbefore, an ideal tubular bell has the third to fifth overtones regulated to 2 : 3 : 4. The prior art tubular bell for the note C52 had the third to fifth overtones with the frequency ratio of 525.6 : 775.8 : 1067.2 = 2 : 2.952 : 4.061, and the other prior art tubular bells were also deviated from the frequency ratio of 2 : 3 : 4. Moreover, the frequency difference showed a different tendency between the fourth overtone and the fifth overtone. As shown in figure 2, the frequency difference of the fourth overtones f4 was plotted on line PL1, and had negative values. On the other hand, the frequency difference of the fifth overtones f5 was plotted on line PL2. and had positive values. Thus, the fourth overtones f4 were deviated in the opposite direction to the fifth overtones f5, and this tendency makes the solution complicated. A solution against the problem is proposed in U.S. Patent No. 2,273,333, and the chimes disclosed in the U.S. Patent consists of metallic tubes partially constricted. However, the partially constricted metallic tubes require a complicated process to form it, and are too heavy. For this reason, the tubular bells disclosed in the U.S. Patent are not practical. SUMMARY OF THE INVENTION It is therefore an important object of the present invention to provide tubular bells which generate sounds each having the third to fifth overtones exactly adjusted to the ideal frequency ratio of 2 : 3 : 4. To accomplish the object, the present invention proposes to attach a weight at a node of a fourth overtone generated in a tubular bell. The weight does not have an influence on the frequency of the fourth overtone; however, the weight is effective against the improper frequency of a third overtone and the improper frequency of a fifth overtone. If a tuner properly selects the weights at selected nodes, the third to fifth overtones are regulated to the frequency ratio of 2 : 3 : 4. In accordance with the present invention, there is provided a percussion instrument comprising: a frame structure; a plurality of vibrative tube members; and a plurality of weight members attached to the plurality of vibrative tube members at or around nodal points of the tube members. BRIEF DESCRIPTION OF THE DRAWINGS The features and advantages of the tubular bells according to the present invention will be more clearly understood from the following description taken in conjunction with the accompanying drawings in which: Fig. 1 is a view showing the relation of the fundamental tone and overtones between the notes generated by the prior art tubular bells; Fig. 2 is a graph showing the frequency difference from the target frequency; Fig. 3 is a perspective view showing the structure of tubular bells according to the present invention; Fig. 4 is a side view showing a metallic tube incorporated in the tubular bells; Fig. 5 is a partially cut away side view showing the metallic tube; Fig. 6 is a cross sectional view taken along line A-A of figure 5 and showing a ring member fixed to the tube member together with spacer pads; Fig. 7 is a partially cut away side view showing the metallic tube incorporated in tubular bells according to the present invention; Fig. 8 is a cross sectional view taken along line B-B and showing a ring member fixed to the inner surface of a metallic tube member; Fig. 9 is a partially cut away side view showing a part of a metallic tube incorporated in tubular bells implementing the third embodiment; Fig. 10 is a cross sectional view taken along line C-C of figure 9 and showing a disk-shaped weight member; Fig. 11 is a partially cut away side view showing a part of a metallic tube incorporated in tubular bells implementing the fourth embodiment; Fig. 12 is a cross sectional view taken along line D-D of figure 11 and showing ball-shaped weight members; Fig. 13 is a partially cut away side view showing a part of a metallic tube incorporated in tubular bells implementing the fifth embodiment; Fig. 14 is a cross sectional view taken along line E-E of figure 13 and showing another disk-shaped weight member; Fig. 15 is a partially cut away side view showing a part of a metallic tube incorporated in tubular bells implementing the sixth embodiment; Fig. 16 is a cross sectional view taken along line F-F of figure 15 and showing block-shaped weight members; and Fig. 17 is a cross sectional view showing other block-shaped weight members incorporated in the seventh embodiment. DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment Referring to figure 3 of the drawings, chimes or tubular bells embodying the present invention largely comprises a movable rack 1, a plurality of metallic tubes 2 and an absorber 3. The plurality of metallic tubes 2 are suspended from the rack 1 by means of strings (not shown), and the absorber 3 takes up the vibrations of the metallic tubes 2. The movable rack 1 includes a frame 1a and four casters 1b. The frame 1a is supported by the four casters 1b, and the four casters 1b allow a player to smoothly move the tubular bells to an arbitrary place. The plurality of metallic tubes 2 are suspended from upper lateral bars 1c of the frame 1a by means of strings, and are different in length from one another. The metallic tubes 2 are formed of brass. The metallic tubes 2 are arranged in two rows, and notes of a scale are assigned to the metallic tubes 2, respectively. The metallic tubes in the front row are corresponding to the white keys of a piano, and the metallic tubes in the rear row produce sounds corresponding to the piano tones generated by depressing black keys. As shown in figure 4, each of the metallic tubes 2 includes a straight tube member 2a open at both ends thereof and a head plug 2b partially inserted into the upper end of the tube member 2a. A player strikes the head plug 2b with a wood hammer (not shown), and causes the metallic tube 2 to vibrate. The head plug 2b effectively eliminates an impact noise from the sound generated by the metallic tube 2. The tube members 2a are 2.3 millimeters in thickness, 38.1 millimeters in outer diameter and 33.5 millimeters in inner diameter. On the other hand, the head plug 2b is 42.5 millimeters in outer diameter D1, and is inserted into the tube member 2a by L1 = 25.5 millimeters (see figure 5). As a result, the head plug 2b projects from the tube member 2a by A = 8 millimeters. An aperture 2x is formed in a central area of the head plug 2b, and the aperture 2x has an inner diameter of the order of 13 millimeter. The aperture 2x connects the inner space of the tube member 2a to the air. The metallic tubes 2 are tuned in such a manner that the third overtones f3 determine the notes of the sounds as follows. A tuner firstly tunes the third overtone f3 by cutting the length of each tube member 2a plugged with the head plug 2b. In the tuning work for the third overtone f3, if the third overtone f3 is still lower than the target frequency, the tuner slightly cuts the tube member 2a, again. On the other hand, the third overtone f3 is higher than the target frequency, the tuner adds a weight to the tube member 2. However, the third overtone f3 is not adjusted to the target frequency in this stage, and the length is slightly shorter than the length for exactly adjusting the third overtone f3 to the target frequency as will be described hereinlater. Original metallic tubes are longer than the metallic tubes 2 before the tuning work. The original metallic tube for the lowest note C52 is 1614 millimeters long, and the original metallic tube for the highest note G71 is 909 millimeters long. Turning back to figure 4, each of the metallic tubes 2 further includes ring members 2c, 2d and 2e attached to the tube member 2a. The ring members 2c, 2d and 2e give additional weight to the tube member 2a, and are formed of metal such as, for example, brass, iron, lead, copper or aluminum. Three to six ring members are attached to the tube member 2a, and are spaced apart from one another in a longitudinal direction of the tube member 2a. As described hereinbefore, the tube member 2a was cut to be shorter than the length where the third overtone f3 was adjusted to the target frequency. When the manufacturer determines the amount of overcuting, the ring members 2c to 2e are taken into account. For this reason, when the ring members 2c to 2e are attached to the tube member 2a, the third overtone f3 is adjusted to the target frequency. The ring members 2c to 2e are positioned at or in the vicinity of nodal points where nodes of the fourth overtone f4 take place, and the ring members 2c to 2e adjust the frequency ratio between the third to fifth overtones to 2 : 3 : 4. The reason why the ring members 2c to 2e are attached to the nodal points is that the fourth overtone f4 is lower than the target frequency (see figure 2), and the ring members 2c to 2e at the nodal points decrease the frequencies of the third and fifth overtones f3 and f5 without reduction of the frequency of the fourth overtone f4. The ring members 2c to 2e are larger in diameter than the tube member 2a, and spacer pads 2f are inserted between the ring members 2c to 2e and the tube member 2a. The spacer pads 2f are formed of synthetic resin, and block the tube member 2a from the undesirable influence of the ring members 2c to 2e. Thus, the ring members 2c to 2e do not impede the vibrations of the tube member 2a by virtue of the spacer pads 2f, and the metallic tube 2 freely vibrates upon impact with the wood hammer. Each of the ring members 2c to 2e is fixed to the tube member 2a together with the spacer pads 2f by means of rivets 2g. The rivets 2g are angularly spaced from one another at 90 degrees (see figure 6). The present inventor evaluated the tubular bells shown in figures 3 to 7. The first example 2 was prepared for the note C52. The metallic tube 2 was 1583 millimeters long, and the head plug 2b was 140 grams. The three ring members 2c to 2e were fixed to the metallic tube 2, and the positions and the weights of the ring members 2c to 2e were shown in Table 1. Ring Member Position (mm) Weight (gram) 2c X1 = 417.0 57.5 2d X2 = 663.0 40.0 2e X3 = 938.0 40.0 "X1", "X2" and "X3" represented the distances from the lower end as shown in figure 4. The present inventor struck the metallic tube with a wood hammer, and measured the third to fifth overtones f3, f4 and f5. The third overtone f3, the fourth overtone f4 and the fifth overtone f5 had respective frequencies at 525.835 Hz, 788.739 Hz and 1051.412 Hz. The frequency ratio between the third to fifth overtones f3/f4/f5 was 2 : 2.9999 : 3.9990. The frequency ratio of the third to fifth overtones was much closer to the target frequency ratio of 2 : 3 : 4 than the frequency ratio of the prior art metallic tube. Ring members were also attached to the nodal points of the fourth overtones generated in the other metallic tubes 2, respectively, and were regulated to appropriate weights. When the present inventor struck the metallic tubes 2, the sounds exactly took place at the notes of the scale, and the present inventor confirmed that the weight members at the nodal points effectively tuned the sounds to the note of the scale. The second example was 1582 millimeters long, and the head plug 2b was 140 grams. Three ring members 2c to 2e were attached to the tube member 2a as shown in Table 2. Ring Member Position (mm) Weight (gram) 2c X1 = 662.0 43.0 2d X2 = 938.0 46.0 2e X3 = 1172.0 53.5 The present inventor struck the metallic tube with the wood hammer, and measured the third to fifth overtones f3, f4 and f5. The third overtone f3, the fourth overtone f4 and the fifth overtone f5 had respective frequencies at 525.678 Hz, 788.426 Hz and 1051.584 Hz. The frequency ratio between the third to fifth overtones f3/f4/f5 was 2 : 2.9997 : 4.0009. The frequency ratio of the third to fifth overtones was much closer to the target frequency ratio of 2 : 3 : 4 than the frequency ratio of the prior art metallic tube. The third example was 1583 millimeters long, and the head plug 2b was 140 grams. Three ring members 2c to 2e were attached to the tube member 2a as shown in Table 3. Ring Member Position (mm) Weight (gram) 2c X1 = 422.0 44.5 2d X2 = 925.0 64.0 2e X3 = 1241.0 71.0 The present inventor struck the metallic tube with the wood hammer, and measured the third to fifth overtones f3, f4 and f5. The third overtone f3, the fourth overtone f4 and the fifth overtone f5 had respective frequencies at 525.765 Hz, 788.566 Hz and 1051.443 Hz. The frequency ratio between the third to fifth overtones f3/f4/f5 was 2 : 2.9997 : 3.9997. The frequency ratio of the third to fifth overtones was much closer to the target frequency ratio of 2 : 3 : 4 than the frequency ratio of the prior art metallic tube. The fourth example was 1584 millimeters long, and the head plug 2b was 140 grams. Three ring members 2c to 2e were attached to the tube member 2a as shown in Table 4. Ring Member Position (mm) Weight (gram) 2c X1 = 412.0 37.0 2d X2 = 655.0 65.5 2e X3 = 1211.0 45.5 The present inventor struck the metallic tube with the wood hammer, and measured the third to fifth overtones f3, f4 and f5. The third overtone f3, the fourth overtone f4 and the fifth overtone f5 had respective frequencies at 525.715 Hz, 788.741 Hz and 1051.493 Hz. The frequency ratio between the third to fifth overtones f3/f4/f5 was 2 : 3.0006 : 4.0002. The frequency ratio of the third to fifth overtones was much closer to the target frequency ratio of 2 : 3 : 4 than the frequency ratio of the prior art metallic tube. The fifth example was 1583 millimeters long, and the head plug 2b was 140 grams. Four ring members 2c to 2f were attached to the tube member 2a as shown in Table 5. Ring Member Position (mm) Weight (gram) 2c X1 = 97.0 18.0 2d X2 = 417.0 55.5 2e X3 = 665.0 40.0 2f X4 = 930.0 40.0 The ring member next to the third ring member 2e was labeled with "2f", and "X4" indicated the distance from the lower tube end position to the ring member 2f. The present inventor struck the metallic tube with the wood hammer, and measured the third to fifth overtones f3, f4 and f5. The third overtone f3, the fourth overtone f4 and the fifth overtone f5 had respective frequencies at 526.072 Hz, 788.676 Hz and 1051.362 Hz. The frequency ratio between the third to fifth overtones f3/f4/f5 was 2 : 2.9984 : 3.9970 The frequency ratio of the third to fifth overtones was much closer to the target frequency ratio of 2 : 3 : 4 than the frequency ratio of the prior art metallic tube. The sixth example was 1583 millimeters long, and the head plug 2b was 140 grams. Four ring members 2c to 2f were attached to the tube member 2a as shown in Table 6. Ring Member Position (mm) Weight (gram) 2c X1 = 417.0 35.0 2d X2 = 665.0 40.0 2e X3 = 903.0 40.0 2f X4 = 1231.0 40.0 The present inventor struck the metallic tube with the wood hammer, and measured the third to fifth overtones f3, f4 and f5. The third overtone f3, the fourth overtone f4 and the fifth overtone f5 had respective frequencies at 525.710 Hz, 788.483 Hz and 1051.776 Hz. The frequency ratio between the third to fifth overtones f3/f4/f5 was 2 : 2.9997: 4.0014. The frequency ratio of the third to fifth overtones was much closer to the target frequency ratio of 2 : 3 : 4 4 than the frequency ratio of the prior art metallic tube. The seventh example was 1582 millimeters long, and the head plug 2b was 140 grams. Four ring members 2c to 2f were attached to the tube member 2a as shown in Table 7. Ring Member Position (mm) Weight (gram) 2c X1 = 662.0 42.0 2d X2 = 940.0 45.0 2e X3 = 1175.0 55.0 2f X4 = 1508.0 18.0 The present inventor struck the metallic tube with the wood hammer, and measured the third to fifth overtones f3, f4 and f5. The third overtone f3, the fourth overtone f4 and the fifth overtone f5 had respective frequencies at 525.666 Hz, 788.688 Hz and 1051.564 Hz. The frequency ratio between the third to fifth overtones f3/f4/f5 was 2 : 3.0007 : 4.0009. The frequency ratio of the third to fifth overtones was closer to the target frequency ratio of 2 : 3 : 4 than the frequency ratio of the prior art metallic tube. The eighth example was 1586 millimeters long, and the head plug 2b was 140 grams. Five ring members 2c to 2g were attached to the tube member 2a as shown in Table 8. Ring Member Position (mm) Weight (gram) 2c X1 = 114.0 20.5 2d X2 = 358.0 35.0 2e X3 = 680.0 40.0 2f X4 = 922.00 42.0 2g X5 = 1235.0 44.0 A ring member next to the fourth ring member 2f was labeled with "2g", and "X" was indicative of the distance from the lower tube end to the fifth ring member 2g. The present inventor struck the metallic tube with the wood hammer, and measured the third to fifth overtones f3, f4 and f5. The third overtone f3, the fourth overtone f4 and the fifth overtone f5 had respective frequencies at 525.760 Hz, 788.690 Hz and 1051.604 Hz. The frequency ratio between the third to fifth overtones f3/f4/f5 was 2 : 3.0002 : 4.0003. The frequency ratio of the third to fifth overtones was much closer to the target frequency ratio of 2 : 3 : 4 4 than the frequency ratio of the prior art metallic tube. The ninth example was 1586 millimeters long, and the head plug 2b was 140 grams. Five ring members 2c to 2g were attached to the tube member 2a as shown in Table 9. Ring Member Position (mm) Weight (gram) 2c X1 =375.0 34.0 2d X2 = 680.0 43.0 2e X3 =923.0 43.0 2f 0 X4 = 1229.0 46.0 2g X5 = 1491.0 16.0 The present inventor struck the metallic tube with the wood hammer, and measured the third to fifth overtones f3, f4 and f5. The third overtone f3, the fourth overtone f4 and the fifth overtone f5 had respective frequencies at 525.833 Hz, 788.645 Hz and 1051.604 Hz. The frequency ratio between the third to fifth overtones f3/f4/f5 was 2 : 2.9996 : 3.9998. The frequency ratio of the third to fifth overtones was much closer to the target frequency ratio of 2 : 3 : 4 than the frequency ratio of the prior art metallic tube. The tenth example was 1586 millimeters long, and the head plug 2b was 140 grams. Six ring members 2c to 2h were attached to the tube member 2a as shown in Table 10. Ring Member Position (mm) Weight (gram) 2c X1 = 118.0 20.0 2d X2 = 373.0 33.5 2e X3 = 683.0 42.5 2f X4 = 927.0 42.5 2g X5 = 1229.0 44.5 2h X5 = 1496.0 20.0 A ring member next to the fifth ring member 2g was labeled with "2h", and "X6" was indicative of the distance from the lower tube end to the sixth ring member 2h. The present inventor struck the metallic tube with the wood hammer, and measured the third to fifth overtones f3, f4 and f5. The third overtone f3, the fourth overtone f4 and the fifth overtone f5 had respective frequencies at 525.624 Hz, 788.445 Hz and 1051.332 Hz. The frequency ratio between the third to fifth overtones f3/f4/f5 was 2 : 3.0000 : 4.0003. The frequency ratio of the third to fifth overtones was much closer to the target frequency ratio of 2 : 3 : 4 4 than the frequency ratio of the prior art metallic tube. As will be understood from the foregoing description, the tubular bells according to the present invention exactly generate the sounds with the notes of the scale by virtue of the weight added to or around the nodal points of the fourth overtone f4. Second Embodiment Turning to figures 7 and 8 of the drawings, another metallic tube 12 incorporated in tubular bells largely comprises a metallic tube member 12a, a head plug 12b inserted into an upper end of the metallic tube member 12a and a plurality of ring members 12c fixed to the metallic tube member 12a at intervals. Although figure 7 shows only one ring member 12c, those ring members 12c were positioned at or around nodal point where nodes of the fourth overtone f4 take place. The ring members 12c are smaller in diameter than the metallic tube member 12a, and are loosely insertable into the inner space of the metallic tube member 12a. Spacer pads 12d are partially embedded into the outer surface portion of each of the ring members 12c at intervals, and each of the ring members 12c is fixed to the metallic tube member 12a together with the spacer pads 12d by means of rivets 12e. The ring members 12c with the spacer pads 12d are attached to a suitable jig (not shown), and the jig is inserted into the inner space of the metallic tube member 12a together with the ring members 12c. A worker fastens the ring members 12c with the rivets 12e at intervals along the longitudinal direction of the metallic tube member 12a. The present inventor confirmed the frequency ratio of the third to fifth overtones f3, f4 and f5 closer to the target frequency ratio of 2 : 3 : 4 as similar to the first embodiment. The sounds exactly take place at the notes of the scale, and the tubular bells of the second embodiment are superior in the external appearance to the first embodiment. Third Embodiment Turning to figures 9 and 10, a disk-shaped weight member 22a is fixed to a metallic tube member 22b by means of rivets 22c. Though allmnot shown in figures 9 and 10, the disk-shaped weight member 22a and other disk-shaped weight members are positioned at or around nodal points where the nodes of the fourth overtone take place. Spacer pads 22d are inserted between each of the disk-shaped weight members 22a and the metallic tube member 22b. Although the disk-shaped weight members 22a divide the inner space of the metallic tube member 22b into sub-spaces, four apertures 22e are formed in each of the disk-shaped weight members 22a, and connect the sub-spaces to one another. The present inventor confirmed the frequency ratio of the third to fifth overtones f3, f4 and f5 closer to the target frequency ratio of 2 : 3 : 4 as similar to the first embodiment. The sounds exactly take place at the notes of the scale, and the tubular bells of the third embodiment are also superior in the external appearance to the first embodiment. Fourth Embodiment Turning to figures 11 and 12, ball-shaped weight members 32a are fixed to a metallic tube member 32b by means of rivets 32c. Though not shown in figures 11 and 12, the set of ball-shaped weight members 22a and other sets of ball-shaped weight members are positioned at or around nodal points where the nodes of the fourth overtone take place. Spacer pads 32d are inserted between each of the ball-shaped weight members 32a and the metallic tube member 32b. The present inventor confirmed the frequency ratio of the third to fifth overtones f3, f4 and f5 closer to the target frequency ratio of 2 : 3 : 4 as similar to the first embodiment. The sounds exactly take place at the notes of the scale, and the tubular bells of the fourth embodiment are also superior in the external appearance to the first embodiment. Fifth Embodiment Turning to figures 13 and 14, a disk-shaped weight member 42a is fixed to a metallic tube member 42b by means of rivets 42c. Though not shown in figures 13 and 14, the disk-shaped weight member 42b and other disk-shaped weight members are positioned at or around nodal points where the nodes of the fourth overtone take place. Spacer pads 42d are inserted between each of the disk-shaped weight member 42a and the metallic tube member 42b. The present inventor confirmed the frequency ratio of the third to fifth overtones f3, f4 and f5 closer to the target frequency ratio of 2 : 3 : 4 as similar to the first embodiment. The sounds exactly take place at the notes of the scale. Sixth Embodiment Turning to figures 15 and 16, a set of block-shaped weight members 52a are fixed to a metallic tube member 52b by means of rivets 52c. Though not shown in figures 15 and 16, the set of block-shaped weight members 52a and other sets of block-shaped weight members are positioned at or around nodal points where the nodes of the fourth overtone take place. Spacer pads 52d are inserted between the block-shaped weight members 52a and the metallic tube member 52b. The present inventor confirmed the frequency ratio of the third to fifth overtones f3, f4 and f5 closer to the target frequency ratio of 2 : 3 : 4 as similar to the first embodiment. The sounds exactly take place at the notes of the scale. Seventh Embodiment Turning to figure 17 of the drawings, eight block-shaped weight members 62a are angularly spaced around a metallic tube member 62b at intervals, and form in combination a set of weight members. The block weight members 62a are fixed to the outer surface of the metallic tube member 62b by means of rivets 62c, and spacer pads 62d are inserted between the block-shaped weight members 62a and the outer surface of the metallic tube member 62b. The set of block-shaped weight members 62a and other sets of block-shaped weight members are positioned at or around nodal points where nodes of the fourth overtone f4 take place. The present inventor confirmed the frequency ratio of the third to fifth overtones f3, f4 and f5 closer to the target frequency ratio of 2 : 3 : 4 as similar to the first embodiment. The sounds exactly take place at the notes of the scale. Even if the ring members are slightly deviated from the nodal points, the ring members effectively regulate the third overtone f3, the fourth overtone f4 and the fifth overtone f5 to the frequency ratio of 2 : 3 : 4. The allowable deviation ranges from zero percent to 25 percents of the wavelength of the fourth overtone f4. The present inventor measured the frequency deviation for the first to tenth examples, and the results were summarized in Table 11. Example Node Average Distance between Nodes (mm) 1st. 2nd. 3rd. 4th. 5th. 6th. 1 - 17.9 2.5 1.5 - - 282.6 2 - - 0.7 5.9 23.6 - 282.4 3 - 21.1 - 6.2 0.1 - 282.6 4 - 16.7 0.0 - 10.9 - 282.7 5 0.1 17.8 3.6 5.6 - - 282.6 6 - 18.5 2.4 24.1 4.0 - 282.6 7 - - 0.6 7.4 22.5 0.1 282.4 8 5.6 2.4 6.3 9.7 3.6 - 282.8 9 - 4.7 6.4 9.3 3.5 8.1 283.6 10 7.0 3.2 6.4 7.9 4.3 6.4 283.2 Mini. 0.1 2.4 0.0 1.5 0.1 0.1 0.0 Max. 7.0 21.1 6.4 24.1 23.6 8.1 24.1 In table 11, the average distance was calculated as ((position of 6th. node) - (position of 1st. node))/ 5, and the distance between the ring member and the closest node of the fourth overtone f4 was divided by the average distance for the deviation in percent. As will be understood from table 11, the actual deviation ranges from zero percent to 24.1 percent, and the present inventor decided that the allowable deviation was between zero to 25 percent. Although particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the scope of the present invention as defined by the claims. For example, other tubular bells may be formed of different materials and have different dimensions. The present invention is applicable to another percussion instrument with vibrative tubes in so far as the notes of sounds are affected by a set of overtones. The set of overtones may be different from the third to fifth overtones.

Claims: A percussion instrument comprising: a frame structure (1); a plurality of vibrative tube members (2a/ 12a/ 22b/ 32b/ 42b/ 52b/ 62b); characterized in that a plurality of weight members (2c-2e/ 12c/ 22a/ 32a/ 42a/ 52a/ 62a) are attached to said plurality of vibrative tube members at or around nodal points of said plurality of vibrative tube members. The percussion instrument as set forth in claim 1, wherein said frame structure (1) supports said plurality of vibrative tube members (2a/ 12a/ 22b/ 32b/ 42b/ 52b/ 62b), which generate sounds with notes of a scale through vibrations thereof, a set of overtones (f3/f4/f5) of each of said sounds having an influence on the note of said scale; and said plurality of weight members (2c-2e/ 12c/ 22a/ 32a/ 42a/ 52a/ 62a) are selectively attached to said plurality of vibrative tube members (2a/ 12a/ 22b/ 32b/ 42b/ 52b/ 62b) at or around said nodal points where nodes of a certain overtone selected from said set of overtones take place in one of said plurality of vibrative tube members, thereby causing said overtones of said set to have respective frequencies regulated to a predetermined frequency ratio. The percussion instrument as set forth in claim 2, in which said plurality of vibrative tube members (2a) are suspended from a bar member (1c) forming a part of said frame structure (1) so that said percussion instrument serves as tubular bells. The percussion instrument as set forth in claim 3, in which said set of overtones consists of a third overtone (f3), a fourth overtone (f4) and a fifth overtone (f5), said certain overtone is the fourth overtone (f4), and said predetermined frequency ratio is 2 : 3 : 4. The percussion instrument as set forth in claim 2, in which said weight members (2c-2e) are fixed to one of said plurality of vibrative tube members (2a) at intervals in a longitudinal direction of said one of said plurality of vibrative tube members. The percussion instrument as set forth in claim 5, in which said weight members (2c-2e/ 42a/ 52a/ 62a) are fixed to an outer surface of said one of said plurality of vibrative tube members (2a/ 42b/ 52b/ 62b). The percussion instrument as set forth in claim 6, in which each of said weight members (52a/ 62a) are divided into weight sub-members spaced apart from one another along the circumference of said outer surface of said one of said plurality of vibrative tube members (52b/ 62b). The percussion instrument as set forth in claim 6 or 7, further comprising spacer members (2f/ 42d/ 52d/ 62d) provided between said outer surface and said weight members for preventing said one of said plurality of vibrative tube members from an influence of said weight members. The percussion instrument as set forth in claim 5, in which said weight members (12c/ 22a/ 32a) are fixed to an inner surface of said one of said plurality of vibrative tube members (12a/ 22b/ 32b). The percussion instrument as set forth in claim 9, in which each of said weight members (32a) are divided into weight sub-members spaced apart from one another along the circumference of said inner surface of said one of said plurality of vibrative tube members,and preferably further comprising spacer members (12d/ 22d/ 32d) provided between said inner surface and said weight members for preventing said one of said plurality of vibrative tube members from an influence of said weight members.

Inventors: FUJII JUNJI, FUJII, JUNJI, Fujii, Junji, Yamaha Corp.
Applicants: YAMAHA CORP, YAMAHA CORPORATION
Application year: 1996
Main classification: G10D13
IPC codes: G10D13, G10K1