JP7178533B2 - A lip plate with a rough surface for improving the sounding efficiency of the flute. - Google Patents

Description

The present invention relates to a lip plate having a roughened surface for improving the sounding efficiency of a flute.

Traditionally, if the lip plate of a flute is made of metal, the end is simply cut off. Those with a lip plate embossed on the head joint had a shape in which the sloping portion between the lip plate and the head joint was finished by polishing. A flute with such a lip plate is difficult to produce a low tone quickly and stably. ~15”, even experts had a hard time.

"Non-Patent Document 3" describes in a bird's-eye view the research up to 1992 in Europe, America and Japan on the physics of air reed instruments including flutes. What is being done there is research on what kind of function should be used and how to process the airflow blown into the mouthpiece and the corresponding sound waves to match the experimental values. It was confirmed that similar research activities are continuing to this day. It is thought that such research was the mainstream, and researchers were not interested in where and how air currents containing sound wave information flowed.

JP 2009-271481 Patent No. 6744509 JP 2020-046508 JP 2017-68110 real climbing 3229586

Yoshinori Ando, Acoustics of Musical Instruments, Ongaku no Tomosha, 1971 Yusuke Ando "Exploring the Tones of Musical Instruments" Chuko Shinsho Shigeru Yoshikawa, "Physics and Tones of Air Reed Instruments", Journal of the Acoustical Society of Japan, Vol.49, No.3, p. 193-202 Kimiya Takahashi and Kensuke Ikeda, "Non-linear Phenomenon of Wind Instrument Sounds and Their Interpretations", Physics Research (1995), 64(1): 26-88 Hirofumi Onitsuka, "Prediction Simulation of Fluid and Acoustic Characteristics of Air Reed Instruments" HPCI System Utilization Research Project User Report "Sonorite" by Marcel Moyse Masahiro Arita "Works for Flute" Quarterly Muramatsu No.114 p. 26-29 Story: Shuichi Tanaka "Flute production, its transition" THE FLUTE No. 99 p. 14-16 "THE FLUTE AND FLUTE PLAYING" by Theobald Boehm Yoshinori Ando, "Relationship between Flute Driving Conditions, Generated Sound Pressure Level, and Fundamental Frequency", Acoustical Society of Japan, Vol. 26, No. 6, p. 253-260 Yoshinori Ando, "Relationship between driving conditions of flute and overtone structure", Journal of Acoustical Society of Japan, Vol. 26, No. 7, p. 297-305 Ryozo Ishiwata "Fluid Mechanics" Natsumesha

The problem to be solved is that it is difficult for the flute to quickly and stably generate low frequencies.

Another problem to be solved is to clarify the movement of the airflow that the performer blows into the mouthpiece and the movement of the airflow that contains the sound wave information created by that energy. is to determine the shape of the flute lip plate such that

A lip plate 2 having a rough surface is provided at the end of the lip plate 1 of the flute.

When playing a flute with the lip plate 2 having the rough surface of the present invention, the sound volume increases and low notes can be produced quickly and stably.

The amplitude of the sound waves generated by the flute of the present invention having lip plate 2 with a rough surface in addition to lip plate 1 is averaged over three octaves compared to the sound wave amplitude of a conventional flute with only lip plate 1. Values of over 6 decibels were obtained. When converted to energy, it becomes a little over four times as much. From this result, it is considered that most of the airflow containing sound wave information is flowing over the lip plate together with the airflow caused by the player's breath. In other words, it is thought that the airflow containing sound waves flowing over the lip plate of the conventional flute causes a large loss of sound wave energy due to separation of the flow due to the sudden widening of the flow path at the edge of the lip plate. On the other hand, the rough surface of the lip plate of the present invention is thought to stop the energy of sound waves with a small loss due to the function of the rough surface.

FIG. 1 is a side view near the mouthpiece of a flute having a lip plate with a rough surface according to the present invention. FIG. 2 is a sectional view perpendicular to the tube axis of the head joint at the center of the mouthpiece of a metal flute having a metal lip plate having a rough surface according to the present invention. FIG. 3 is a cross-sectional view perpendicular to the tube axis of the headjoint at the center of the mouthpiece of a flute having a metal headjoint with a wooden lipplate and a wooden lipplate having a rough surface added thereto. Figure 4 shows a flute with a lip plate embossed in a wooden headjoint with a roughened part of the bevel between the lipplate and the headjoint. is a cross-sectional view perpendicular to .

It reveals that much of the airflow, which contains the sonic information, flows over the lip plate along with the airflow generated by the performer, and thus captures much of the sonic energy due to the shape of the traditional flute's lip plate. By recovering the energy of the sound wave by using a lip plate having a rough surface, the missing shortcomings can be easily produced to achieve the low-pitched sound of the flute.

FIG. 1 is a side view near the mouthpiece of a flute having a lip plate 2 having a rough surface according to the present invention. A mouthpiece 3 is provided on the lip plate 1 which is arranged to contact the tube 4 . FIG. 2 is a cross-sectional view perpendicular to the tube axis of the head tube at the center of the flute mouthpiece 3 of the metal head tube 4 in which a metal lip plate 2 having a rough surface is added to the metal lip plate 1. is. The lip plate 1 on the right side of FIG. 2 is where the player's chin and lips are placed, and the lip plate 1 on the left side is where the airflow flows. FIG. 3 is a sectional view perpendicular to the tube axis of the metal head tube 4 in which a wooden lip plate 2 having a rough surface is added to the wooden lip plate 1 at the center of the flute mouthpiece 3. is. Description of the lip plate 1 in FIG. 3 is the same as in FIG. FIG. 4 shows a flute mouthpiece 3 having a wooden head joint 4 with a lip plate 1 embossed and a part 2 roughened on the sloping surface. Fig. 3 is a vertical cross-sectional view; The description of the lip plate 1 in FIG. 4 is the same as in FIG.

I presumed that both the air current that the player blows into the mouthpiece of the flute and the air current that propagates the sound waves generated by that energy flow over the lip plate, but it is necessary to confirm whether this assumption is correct. was there.

Standing waves generated by flutes are known to be open tubes. One of the antinodes of the standing wave is near the mouthpiece, which is the place where the air current where the amplitude of the sound wave is maximum repeats exhalation and inhalation oscillations.

When a standing wave containing sound waves is emitted from the mouthpiece, it is thought that the air current, which is the medium through which the sound waves propagate, overflows from the mouthpiece and flows over the lip plate together with the air current blown by the player.

In the case of the conventional flute, since the lip plate has only the lip plate 1 of FIG. 1, the flow path expands rapidly at the edge of the lip plate, so that the airflow separates and causes a large loss. This is expected to reduce the amplitude and energy of the sound waves.

To prove the conjecture correct, it is necessary to show that the sonic energy increases at the edge of the lip plate 1 to prevent the channel from widening rapidly. Therefore, it is effective to apply fluid dynamics to form a slope from the end of the lip plate 1 and to roughen the surface of the slope with many protrusions or depressions. If the loss of sound wave energy can be reduced by the lip plate 2 having such a rough surface, the prediction is correct, and the sound wave energy generated by the flute is recovered.

Preliminary experiments were conducted to create a rough surface, and five types of white alumina abrasives of different particle sizes, No. 60, No. 120, No. 180, No. 240, and No. 320, were used to form a two-liquid epoxy adhesive. A method of mixing at a ratio of 1:1 and thinly applying to the surface of the lip plate 2 was adopted.

It would be ideal to evaluate all three octave sounds generated by a flute on five types of rough surfaces, but this is inefficient as a preliminary experiment. We decided that it would be appropriate to compare the degree of improvement based on the amplitude of the fundamental tone and the number and amplitude of overtones by evaluating the sound of D4 (approximately 294 Hz), which is a low tone, and evaluated five types of rough surfaces. rice field.

The evaluation method of the rough surface was carried out as follows, with an emphasis on objectivity. A metal lip plate 2 detachable from a metal lip plate 1 was prepared. The head joint is also made of metal. Five rough surfaces were prepared by applying a mixture of an adhesive and an abrasive to the surface of a component shaped like a silver lip plate 2, corresponding to five kinds of abrasives. I placed a recorder 30 centimeters away from the mouthpiece, and recorded myself by playing the metal flute at the strongest note. To avoid distortion, the recording conditions were set to 24 bits and 44.1 kHz. Recorded data is written to a personal computer, played back using the DSD playback function set on the same personal computer, sent to USB, converted to analog by a DA converter, and amplified to a size suitable for observation. However, when performing a series of measurements, the amplification is fixed. This signal was USB-converted and received by another personal computer, and the generation of the fundamental tone and overtones was observed from the screen after the fast Fourier transform. The reason for using the DSD for the playback function is that the waveform of the sound that has been digitized once should be restored to the original waveform as faithfully as possible. In order to compare with the above data, we obtained the data of playing D4 flute with only lip plate 1 without rough surface at the strongest note by the same method as above, and measured the amplitude and number of the fundamental tone and the amplitude and number of overtones. were compared respectively.

Using the fast Fourier transformed image, we evaluated the amplitude of the fundamental tone, the amplitude and the number of occurrences of each of the multiple overtones, and found that there was a difference due to the difference in the grain size of the abrasive used for roughening the surface. Samples using grain size 120 have the largest amplitude of the fundamental tone, and the amplitude of overtones is large and numerous. Samples with particle sizes #60 and 180 followed, and samples with particle sizes #240 and 320 showed little effect.

As a reference, "Reference Figure 1" is a diagram of the fast Fourier transform of D4 sound waves when using a rough surface created using a grain size of 120, and "Reference Figure 2" is created using a grain size of 320. The fast Fourier transform of the D4 sound wave when the rough surface is used, and the fast Fourier transform of the D4 sound wave when the rough surface is not used, that is, in the state of the conventional flute, is shown in "Reference Figure 3". The horizontal axis represents frequency (Hertz) and the vertical axis represents the relative level of amplitude in decibels.

Reference diagram 1

Reference diagram 2

Reference diagram 3

A detailed comparison of the sound of the conventional flute and the flute of the present invention was carried out. The sound of a conventional flute having only a metal lip plate 1 was recorded and analyzed, and then an abrasive with a grain size of 120 was applied to the entire surface of a metal plate with a length of 35 mm and a width of 5 mm cut off at both ends of a crescent moon. was mixed with an adhesive and attached to the lip plate 1, the lip plate having the rough surface of the present invention was constructed and recorded and analyzed. In this way, the experiment was conducted without individual differences in metal flutes.

When recording the sound, the recording specification was set to 24-bit, 44.1 kilohertz and the distance between the recorder and the flute was 30 centimeters in front of the mouthpiece. Transfer recorded sound data to a computer, convert the signal to DSD on the computer, convert it to an analog signal with a DA converter via USB, send it to an acoustic amplifier, and then observe the result of the fast Fourier transform. The output of the acoustic amplifier was received by another personal computer via a USB converter and subjected to fast Fourier transform to decompose the sound into frequency information data.

In order to produce sound from a flute, it is preferable to use a mechanical system because the air velocity can be set in detail. Experiments were carried out by carefully blowing as hard as possible to reduce variations in each sound.

The notes produced using the flute are three octaves of the C major scale, that is, the note names written in German are C4, D4, E4, F4, G4, A4, H4, C5, D5, E5, F5, 21 notes of G5, A5, H5, C6, D6, E6, F6, G6, A6, H6.

A conventional flute having only the lip plate 1 was used to record 21 pitch names in a recorder, and then the flute provided with the lip plate having the rough surface of the present invention was used to record the same 21 pitch names. recorded the sound of The data of the recorded sounds were processed according to the procedure described above, and amplitude data of fundamental tones and overtones subjected to fast Fourier transform were obtained for each pitch name.

It is reported in "Non-Patent Document 2, p. 143" that the overtone generation of the flute varies greatly among individuals. In order to avoid this effect, only the amplitude value of the frequency corresponding to the note name was used as data for comparison, and other overtone information was not used. "Table 1" shows the results for a conventional flute and a metal flute using the flute of the present invention.

From the results of "Table 1", the amplitude generated by the flute using the lip plate 2 having a rough surface of the present invention is 6 dB on average over three octaves than the amplitude generated by the conventional flute. was shown to be greater. 6 decibels is twice as much, and since the energy is the square of the amplitude, the result is a little over four times greater. This result supports the idea that when sound vibrations exit the mouthpiece, an air current containing sound wave information overflows the mouthpiece and flows over the lip plate along with the air currents blown by the player. In addition, since the flute using the lip plate 2 having a rough surface of the present invention prevents separation of the airflow, the energy of the sound waves originally generated by the flute is recovered, resulting in all sounds including low sounds. It is thought that this indicates the effect of making it easier to produce sound. The configuration used in this experiment basically conformed to FIG. 1, and the detailed configuration conformed to FIG.

Two types of samples were evaluated for the surface roughness of the roughened surface with a measuring instrument. One is a rough surface made by mixing a 120-grain abrasive with an epoxy-based adhesive in a volume ratio of 1:1 and thinly applying it to create numerous projections. It is a rough surface in which about 200 small pits are made using a diamond engraver with a sphere of about 2 mm. Expressed as the arithmetic mean roughness (Ra) of the Japanese Industrial Standard, the rough surface of the protrusions using abrasive No. 120 was approximately 5 micrometers, and the rough surface of the recesses made with an engraver was 12 micrometers. It has been confirmed that these two rough surfaces exhibit substantially the same sound improvement effect as the rough surface of the lip plate 2 . A rough surface formed by projections causes resistance to airflow, that is, loss of energy, so a roughened surface formed by depressions is preferable. That's the reason. After that, 250 dents were additionally machined. There is no difference from 200 except that C4 is increased by 5 dB. The arithmetic mean roughness (Ra) is 15 micrometers due to the increase in the depressions.

When playing a similarly cold flute at a room temperature of 10 degrees Celsius or less, on the lip plate 1, from the mouthpiece 3 towards the edge of the lip plate 1, as shown in "reference picture 1", It can be observed that water droplets are lined up with a width similar to the width of the mouthpiece. From this, it is presumed that the air current flowing over the lip plate 1 during flute performance is approximately the same as the width of the mouthpiece. A mouthpiece width of 12 millimeters is recommended by Theobald Böhm on page 4 of [9]. The width of the mouthpieces of the five head joints that I currently own follow this rule. The lip plate 2 having a rough surface does not have any functional problem even if the entire surface is processed with a rough surface. The width of the surface should be 6 mm on each side from the center line of the lip plate 2, and the total width should be 12 mm. I think it's good. The rough surface of the sample in which the dents were made with an engraver, which was used to evaluate the surface roughness of the rough surface, had a width of 20 mm. It is desirable that the gap between the lip plate 2 and the head joint 4 be as small as possible in the range of 20 mm in width near the center of the lower end of the lip plate 2, which has a partially rough surface, but a little less than 1 mm is considered sufficient. . This is because the results in "Table 1" were obtained with that degree of dimensional accuracy. For the same reason, the gap between the partially roughened lip plate 2 and the abutting lip plate 1 should be 0.5 mm or less in the central width of 20 mm.

Reference photo 1

For the last 15 years, I have been making my own wooden lip plate for a metal head joint as a hobby. was made by myself, and a part of the lip plate 2 was finished to have a rough surface with a recess using an engraver, and it was confirmed that the flute had almost the same performance as shown in "Table 1". The width of the rough surface was about 20 mm. The total number of depressions is about 200. After that, 250 dents were additionally machined. C4 and D4 are each 4 dB better, but overall it's the same as when 200. An angle A, which will be described later, is about 20 degrees. In manufacturing the wooden lip plate, the basic configuration was shown in FIG. 1, and the configuration of each part was shown in FIG.

Reference photo 2

Apply a thin layer of 120 grit abrasive and 2-liquid epoxy resin adhesive to the elliptical area of the slope of the embossed lip plate of the commercially available wooden head joint, and apply a thin layer of 20 mm wide. made a rough surface. It is shown in "Reference Photo 3". Almost the same performance as "Table 1" was confirmed. The angle A described below is about 25 degrees. The basic configuration follows FIG. 1, and the configuration of each part follows FIG. A lip plate 2 having a rough surface is a portion surrounded by an ellipse in "Reference Photo 3". The width of the rough surface was 20 mm.

Reference photo 3

The angle that the lip plate 1 and the lip plate 2 make when they are butted together is important because if it is too large, the airflow will separate. The lip plate 1 attached to the conventional flute has a slightly different shape depending on the manufacturer, but the cross section has a shape close to a circle. When the cross-sectional shape of the lip plate 2 is straight, the angle A formed by the lip plate 2 and the tangent line of the tip of the center portion of the lip plate 1 on the airflow side, which has a circular cross-section, is shown in "Reference FIG. 4". The angle A when creating "Table 1" was 25 degrees. A lip plate 2 with an angle A of 30 degrees was used to play the low range from C4 to H4, record and play back, obtain frequency characteristics by fast Fourier transform, and compare with the amplitude of the same range of the conventional flute. The result was an average amplitude of 6 decibels for flutes according to the invention. A similar comparison with the conventional flute using a lip plate 2 with an angle A of 35 degrees shows that the flute of the present invention has an average amplitude of 5 decibels greater. A similar comparison with conventional flutes using a lip plate 2 with an angle A of 45 degrees shows that the flutes of the present invention have an average amplitude of just over 3 decibels greater. From the above results, when the cross-sectional shape of the lip plate 2 is straight, it is desirable that the angle A is within 30 degrees. If the angle A is smaller than 20 degrees, the lip plate 2 will not intersect with the head tube 4 and the gap between the lip plate 2 and the head tube 4 will increase, and the airflow may separate, so 20 degrees is the limit.

Reference diagram 4

In "Non-Patent Document 2, p. 136" of previous research on flutes, it is reported that formants occur in the envelope of the overtone spectrum in the bass range. This tone has a nasal ``bae'' and is considered rather objectionable. Overwrite the corresponding image data from the images used in "Table 1", which is data obtained by fast Fourier transforming seven sounds from C4 to H4 using a flute having a lip plate having a rough surface according to the present invention. to confirm the presence or absence of formants. The results are shown in " Reference Figure 5 ". In " Reference Fig. 5 ", it can be seen that the existence of formants is not confirmed from the envelope of the overtone spectrum. That is, there is a possibility that the timbre of the low range is improved. It should be noted that the presence of formants was confirmed from the envelope of the overtone spectrum in the result of overwriting the image data from C4 to H4 in the low range of the conventional flute used as the conventional flute in the same "Table 1". The vertical axis of " Reference Figure 5 " represents the relative level of amplitude in decibels, and the horizontal axis in frequency (Hertz).

[Reference diagram 5]

Since this is an improvement that solves the structural problems of the conventional flute and recovers much of the lost energy, it does not modify or impair the original characteristics of the flute. I understand the above situations correctly, such as the increase in volume, the easier sound to produce, the improvement in adding expression to the music, and the difficulty in producing low-frequency sounds and the improvement in timbre, which were conventional disadvantages. It is expected that new demand will be stimulated when the

The function of the present invention can be used by adding a lip plate 2 having a rough surface to a conventionally used flute having only the lip plate 1 as a component. When making a new flute, it is considered desirable from the functional and aesthetic point of view to connect the lip plate 1 and the lip plate 2 to form an integrated lip plate. If the head joint is made of wood and the lip plate has a embossed shape, the part of the polished slope where the air flow flows can be processed as a rough surface and used. There are examples where a lip plate is pasted on a wooden head joint, but it can be treated in the same way as relief carving.

The description so far has been about flutes, but lip plates 2 having a rough surface can be applied to so-called flutes, such as flutes d'amore, alto flutes, and bass flutes, which have the same shape as the lip plate 1. , and we can expect improvements similar to those of the flute, such as increased volume, ease of producing sounds, and improved timbre. It can be expected to be applied to organization of all genres and music of all genres, and to contribute to related manufacturing industries and related music industries.

1 lip plate 2 lip plate with rough surface 3 mouthpiece 4 head joint

Claims (4)

A metal or wooden flute comprising a lip plate (1) and a lip plate (2), the lip plate (2) being a truncated crescent shaped plate at the circumferential ends of the lip plate is provided continuously, and the lip plate (2) is provided with a rough surface having a minimum of 5 micrometers and a maximum of 15 micrometers in terms of the arithmetic mean roughness (Ra) of the Japanese Industrial Standards, and the lip plate ( A flute in which the angle formed by the lip plate (2) with the tangent of the tip in the circumferential direction of 1) is from 20 degrees at minimum to 45 degrees at maximum. 2. A flute according to claim 1 , characterized in that said rough surface is located in the middle of the lip plate (2) and has a lateral width of at least 20 millimeters and at most 35 millimeters. Metal flutes, namely flutes d'amore, alto flutes and bass flutes, comprising a lip plate (1) and a lip plate (2), in the shape of a truncated crescent on the circumferential edge of the lip plate. The lip plate (2), which is a plate of A flute with a roughened surface and an angle formed by the lip plate (2) with the tangent of the circumferential tip of the lip plate (1) is from 20 degrees to 45 degrees at the maximum . 4. A flute according to claim 3, characterized in that said rough surface is located in the middle of the lip plate (2) and has a lateral width of minimum 20 mm to maximum 35 mm.

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