阅读说明：本技术 一种宽音域埙及其使用方法 (Wide-range Xun (ancient Chinese musical instrument) and using method thereof ) 是由 王胜祥 于 2019-09-20 设计创作，主要内容包括：本发明公开了一种宽音域埙及其使用方法,包括子弹头型腔体及吹口,腔体内部设置有隔板,隔板将腔体分隔为上腔体和下腔体,隔板中心制有通气孔；上腔体的腔壁上制有上指孔组,下腔体的腔壁上制有下指孔组。上述埙的使用方法包括,吹奏吹奏出泛音高音升5、泛音高音6、泛音高音降7。本埙解决了现有埙音域窄、音质差,无法吹奏出两个八度音的问题,具有音域比两个八度还多出一个小三度,使音质、音色在高、中、低音三个音区统一,拓宽了音域、提升了乐器的表现力。(The invention discloses a wide-range Xun and a use method thereof, wherein the wide-range Xun comprises a bullet head type cavity and a mouthpiece, a partition plate is arranged in the cavity, the cavity is divided into an upper cavity and a lower cavity by the partition plate, and a vent hole is formed in the center of the partition plate; the cavity wall of the upper cavity is provided with an upper finger hole group, and the cavity wall of the lower cavity is provided with a lower finger hole group. The usage method of the Xun-holed wind Chinese instrument comprises the steps of playing the overtone high pitch 5, the overtone high pitch 6 and the overtone high pitch 7. This an ancient egg-shaped, holed wind instrument has solved that current an ancient egg-shaped, holed wind instrument gamut is narrow, tone quality is poor, can't play out the problem of two octaves, has that the gamut still exceeds a little third than two octaves, makes tone quality, tone quality unified in high, well, three register of bass, has widened the gamut, has promoted the expressive force of musical instrument.)

1. A wide-range Xun (ancient egg-shaped, holed wind instrument) comprises a bullet head-shaped cavity and a mouthpiece, and is characterized in that a partition plate is arranged in the cavity, the cavity is divided into an upper cavity and a lower cavity by the partition plate, and a vent hole is formed in the center of the partition plate; the cavity wall of the upper cavity is provided with an upper finger hole group, and the cavity wall of the lower cavity is provided with a lower finger hole group.

2. The wide range, holey wind instrument, as claimed in claim 1, wherein said partition is located forty-six to forty-nine percent of the height of the bullet-shaped chamber; the baffle extends radially inward along the cavity.

3. A broad range, holey wind instrument, according to claim 1 or 2, wherein said upper set of fingerholes comprises fingerhole eight and fingerhole four; the lower finger hole group comprises a finger hole seven, a finger hole six, a finger hole five, a finger hole three, a finger hole two and a finger hole one; the lower finger hole group also comprises a finger hole nine and a finger hole ten.

4. The wide range Xun, according to claim 3, wherein said finger holes seven, six, nine and ten are elliptical holes; the finger hole five, the finger hole three, the finger hole two and the finger hole one are all in a circular truncated cone-shaped structure with a small outer part and a large inner part.

5. The wide range Xun, according to claim 3, wherein the volume ratio of said upper cavity to said lower cavity is 4-5:6-5, the thickness of said partition is 5-7mm, and the diameter of said ventilation hole is 15-18 mm.

6. The wide range Xun, according to claim 3, wherein said finger hole three, finger hole two, finger hole one, finger hole four are arranged in the shape of a human left finger; the finger hole seven, the finger hole six, the finger hole five and the finger hole eight are arranged in the shape of a right finger of a person.

7. A method of using a wide range, holey wind instrument, according to claims 1-6, comprising the steps of:

Pressing a finger hole III, a finger hole II, a finger hole I, a finger hole IV and a finger hole ten corresponding to the left-hand finger shape, wherein the finger hole ten corresponds to the left-hand thumb; simultaneously pressing a finger hole nine, a finger hole eight, a finger hole seven, a finger hole six and a finger hole five corresponding to the right finger type, wherein the finger hole nine corresponds to the thumb of the right hand;

When more than two octaves need to be played, opening finger hole two, finger hole three, finger hole four, finger hole six and finger hole seven to blow, and playing harmonic high lift 5; opening finger hole two, finger hole three, finger hole four, finger hole five, finger hole six, finger hole seven, finger hole eight and finger hole nine, and performing half-hole ultra-blowing to play overtone high pitch 6; opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V, finger hole VI, finger hole VII, finger hole eight, finger hole nine and finger hole Ten-half-hole ultra-blowing to play the harmonic high pitch drop 7;

When the overlapped tones of the small third-degree tones are played, the real-tone high tone 3 can be played by opening the finger hole I, the finger hole II, the finger hole III, the finger hole IV, the finger hole V, the finger hole VI, the finger hole VII, the finger hole IX and the finger hole eleven; opening a finger hole I, a finger hole II, a finger hole III, a finger hole IV, a finger hole V, a finger hole VI, a finger hole VII, a finger hole VIII and a finger hole Ten to play so as to play the real-tone treble 4; the finger hole is completely blocked and blown to play a harmonic high pitch 3; the harmonic high pitch 4 can be played by opening the finger hole eight-stage ultrasonic blowing.

8. A method of using a wide range, holey wind instrument, according to claims 1-6, comprising the steps of:

Pressing a finger hole III, a finger hole II, a finger hole I, a finger hole IV and a finger hole ten corresponding to the left-hand finger shape, wherein the finger hole ten corresponds to the left-hand thumb; simultaneously pressing a finger hole nine, a finger hole eight, a finger hole seven, a finger hole six and a finger hole five corresponding to the right finger type, wherein the finger hole nine corresponds to the thumb of the right hand;

When more than two octaves need to be played, opening finger hole four, finger hole six, finger hole seven and finger hole eight ultra-blow to play overtone high pitch 5; opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V, finger hole VI, finger hole VII, finger hole VIII and finger hole JiuSUPERBLOW to play overtone high pitch 6; opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V, finger hole VI, finger hole VII, finger hole eight, finger hole nine and finger hole Ten-half-hole ultra-blowing to play the harmonic high pitch drop 7;

When overlapped tones of the minor second degree are played, the real-tone high tone 3 can be played by opening the finger hole I, the finger hole II, the finger hole III, the finger hole IV, the finger hole V, the finger hole VI, the finger hole VII, the finger hole VIII, the finger hole VII and the finger hole VIII; the finger hole is full-blocked and ultra-blown, and the harmonic height 3 can be played.

9. A method of using a wide range, holey wind instrument, according to claims 1-6, comprising the steps of:

Pressing a finger hole III, a finger hole II, a finger hole I, a finger hole IV and a finger hole ten corresponding to the left-hand finger shape, wherein the finger hole ten corresponds to the left-hand thumb; simultaneously pressing a finger hole nine, a finger hole eight, a finger hole seven, a finger hole six and a finger hole five corresponding to the right finger type, wherein the finger hole nine corresponds to the thumb of the right hand;

When more than two octaves need to be played, opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V and finger hole eight ultra-blow to play overtone high tone 5; opening a finger hole I, a finger hole II, a finger hole III, a finger hole IV, a finger hole V, a finger hole VI, a finger hole VII, a finger hole eight and a finger hole nine, and performing half-hole ultra-blowing to play a harmonic high pitch 6; and opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V, finger hole VI, finger hole VII, finger hole eight, finger hole nine and finger hole Ten and half holes for ultra-blowing to play the harmonic high pitch drop 7.

10. A method of using a wide range, holey wind instrument, according to claims 1-6, comprising the steps of:

Pressing a finger hole III, a finger hole II, a finger hole I, a finger hole IV and a finger hole ten corresponding to the left-hand finger shape, wherein the finger hole ten corresponds to the left-hand thumb; simultaneously pressing a finger hole nine, a finger hole eight, a finger hole seven, a finger hole six and a finger hole five corresponding to the right finger type, wherein the finger hole nine corresponds to the thumb of the right hand;

When more than two octaves need to be played, the finger hole is opened to perform octave super-blowing, and the overtone high tone 5 can be played; opening the four and eight ultra-blow finger holes to play the overtone high pitch 6; opening finger hole two, finger hole three, finger hole four, finger hole six, finger hole seven and finger hole eight ultra-blow, and playing overtone high pitch drop 7; and opening finger hole two, finger hole three, finger hole four, finger hole six, finger hole seven, finger hole eight, finger hole nine and finger hole ten and half holes to blow out, and playing the overtone high pitch 7.

Technical Field

The invention relates to the technical field of national wind instruments, in particular to a wide-range Xun and a using method thereof.

Background

An ancient egg-shaped, holed wind instrument is a wind instrument which produces sound by vibrating air mass, the sound is pure and clumsily and is a nature sound, the ancient egg-shaped, holed wind instrument is developed from a wind hole to three finger holes, five finger holes and six finger holes, and the ancient egg-shaped, holed wind instrument is subjected to long years of more than 3000 years. Through the recent diligent research of a few people, the number of finger holes is increased, the range is expanded, two octaves can be played, but the defects still exist, for example, when a body sound is made into a low sound 5, a real sound can be improved to a high sound 2, the real sound can be raised to 2, a harmonic can be just two octaves from a high sound 3 to a high sound 5, but the junction of a real sound area and a harmonic area does not overlap, cannot be well connected and smoothly transits, each sound and each half syllable from a lowest sound to a highest sound have corresponding fingering, and when the finger trill of the real sound 2 is played, the finger trill cannot be played.

disclosure of Invention

In order to overcome the defects in the prior art, the invention discloses a wide-range Xun and a using method thereof, and solves the problems that the junction of a real sound area and a harmonic sound area in the prior art is not crossed and overlapped, can not be well connected and stably transited, and cannot play finger tremor.

In order to achieve the purpose, the invention provides the following technical scheme: a wide-range Xun (ancient egg-shaped, holed wind instrument) comprises a bullet head-shaped cavity and a mouthpiece, wherein a partition plate is arranged in the cavity, the cavity is divided into an upper cavity and a lower cavity by the partition plate, and a vent hole is formed in the center of the partition plate; the cavity wall of the upper cavity is provided with an upper finger hole group, and the cavity wall of the lower cavity is provided with a lower finger hole group.

Further, the partition is located at forty-six to forty-nine percent of the height of the bullet-shaped cavity; the baffle extends radially inward along the cavity.

Further, the upper finger hole group comprises a finger hole eight and a finger hole four; the lower finger hole group comprises a finger hole seven, a finger hole six, a finger hole five, a finger hole three, a finger hole two and a finger hole one; the lower finger hole group also comprises a finger hole nine and a finger hole ten.

further, all of the finger holes seven, six, nine and ten are elliptical holes; the finger hole five, the finger hole three, the finger hole two and the finger hole one are all in a circular truncated cone-shaped structure with a small outer part and a large inner part.

Furthermore, the volume ratio of the upper cavity to the lower cavity is 4-5:6-5, the thickness of the partition plate is 5-7mm, and the diameter of the vent hole is 15-18 mm.

Further, the finger hole three, the finger hole two, the finger hole one and the finger hole four are arranged in a left-hand finger shape of a person; the finger hole seven, the finger hole six, the finger hole five and the finger hole eight are arranged in the shape of a right finger of a person.

In order to further illustrate and express the range and the playing effect after the use of the invention, the invention provides a use method as follows:

A using method of a wide-range Xun comprises the following steps:

Pressing a finger hole III, a finger hole II, a finger hole I, a finger hole IV and a finger hole ten corresponding to the left-hand finger shape, wherein the finger hole ten corresponds to the left-hand thumb; simultaneously pressing a finger hole nine, a finger hole eight, a finger hole seven, a finger hole six and a finger hole five corresponding to the right finger type, wherein the finger hole nine corresponds to the thumb of the right hand;

When more than two octaves need to be played, opening finger hole two, finger hole three, finger hole four, finger hole six and finger hole seven to blow, and playing harmonic high lift 5; opening finger hole two, finger hole three, finger hole four, finger hole five, finger hole six, finger hole seven, finger hole eight and finger hole nine, and performing half-hole ultra-blowing to play overtone high pitch 6; opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V, finger hole VI, finger hole VII, finger hole eight, finger hole nine and finger hole Ten-half-hole ultra-blowing to play the harmonic high pitch drop 7;

when the overlapped tones of the small third-degree tones are played, the real-tone high tone 3 can be played by opening the first finger hole, the second finger hole, the third finger hole, the fourth finger hole, the fifth finger hole, the sixth finger hole, the seventh finger hole, the ninth finger hole and the tenth finger hole; opening a finger hole I, a finger hole II, a finger hole III, a finger hole IV, a finger hole V, a finger hole VI, a finger hole VII, a finger hole VIII and a finger hole Ten to play so as to play the real-tone treble 4; the finger hole is completely blocked and blown to play a harmonic high pitch 3; the harmonic high pitch 4 can be played by opening the finger hole eight-stage ultrasonic blowing.

In order to further illustrate and express the range and the playing effect after the use of the invention, the invention provides a use method as follows:

A using method of a wide-range Xun comprises the following steps:

pressing a finger hole III, a finger hole II, a finger hole I, a finger hole IV and a finger hole ten corresponding to the left-hand finger shape, wherein the finger hole ten corresponds to the left-hand thumb; simultaneously pressing a finger hole nine, a finger hole eight, a finger hole seven, a finger hole six and a finger hole five corresponding to the right finger type, wherein the finger hole nine corresponds to the thumb of the right hand;

When more than two octaves need to be played, opening finger hole four, finger hole six, finger hole seven and finger hole eight ultra-blow to play overtone high pitch 5; opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V, finger hole VI, finger hole VII, finger hole VIII and finger hole JiuSUPERBLOW to play overtone high pitch 6; opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V, finger hole VI, finger hole VII, finger hole eight, finger hole nine and finger hole Ten-half-hole ultra-blowing to play the harmonic high pitch drop 7;

when overlapped tones of a small second degree are played, a first finger hole, a second finger hole, a third finger hole, a fourth finger hole, a fifth finger hole, a sixth finger hole, a seventh finger hole, an eighth finger hole, a ninth finger hole and a tenth finger hole are opened to play real-tone high tones 3; the finger hole is full-blocked and ultra-blown, and the harmonic height 3 can be played.

In order to further illustrate and express the range and the playing effect after the use of the invention, the invention provides a use method as follows:

A using method of a wide-range Xun comprises the following steps:

Pressing a finger hole III, a finger hole II, a finger hole I, a finger hole IV and a finger hole ten corresponding to the left-hand finger shape, wherein the finger hole ten corresponds to the left-hand thumb; simultaneously pressing a finger hole nine, a finger hole eight, a finger hole seven, a finger hole six and a finger hole five corresponding to the right finger type, wherein the finger hole nine corresponds to the thumb of the right hand;

when more than two octaves need to be played, opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V and finger hole eight ultra-blow to play overtone high tone 5; opening a finger hole I, a finger hole II, a finger hole III, a finger hole IV, a finger hole V, a finger hole VI, a finger hole VII, a finger hole eight and a finger hole nine, and performing half-hole ultra-blowing to play a harmonic high pitch 6; and opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V, finger hole VI, finger hole VII, finger hole eight, finger hole nine and finger hole Ten and half holes for ultra-blowing to play the harmonic high pitch drop 7.

In order to further illustrate and express the range and the playing effect after the use of the invention, the invention provides a use method as follows:

A using method of a wide-range Xun comprises the following steps:

pressing a finger hole III, a finger hole II, a finger hole I, a finger hole IV and a finger hole ten corresponding to the left-hand finger shape, wherein the finger hole ten corresponds to the left-hand thumb; simultaneously pressing a finger hole nine, a finger hole eight, a finger hole seven, a finger hole six and a finger hole five corresponding to the right finger type, wherein the finger hole nine corresponds to the thumb of the right hand;

When more than two octaves need to be played, the finger hole is opened to perform octave super-blowing, and the overtone high tone 5 can be played; opening the four and eight ultra-blow finger holes to play the overtone high pitch 6; opening finger hole two, finger hole three, finger hole four, finger hole six, finger hole seven and finger hole eight ultra-blow, and playing overtone high pitch drop 7; and opening finger hole two, finger hole three, finger hole four, finger hole six, finger hole seven, finger hole eight, finger hole nine and finger hole ten and half holes to blow out, and playing the overtone high pitch 7.

Compared with the prior art, the invention has the following advantages:

1. A wide-range Xun (ancient egg-shaped, holed wind instrument) comprises a bullet head-shaped cavity and a mouthpiece, wherein a partition plate is arranged in the cavity, the cavity is divided into an upper cavity and a lower cavity by the partition plate, and a vent hole is formed in the center of the partition plate; the cavity wall of the upper cavity is provided with an upper finger hole group, and the cavity wall of the lower cavity is provided with a lower finger hole group. Adopt the scheme of this application can make four kinds of an ancient egg-shaped, holed wind instrument, well joining in marriage an ancient egg-shaped, holed wind instrument, ancient egg-shaped, holed wind instrument of standard promptly. The highly matched Xun can play the overtone high pitch 5, the overtone high pitch 6, the overtone high pitch 7, the real high pitch 3, the real high pitch 4, the overtone high pitch 3 and the overtone high pitch 4, the range of the Xun is one more than two octaves and also one more overlapped small three-degree sound; the Zhongyun Xun can play the overtone high pitch 5, overtone high pitch 6, overtone high pitch 7, real high pitch 3 and overtone high pitch 3, and has one more small third-degree sound and one more overlapped small second-degree sound. The standard Xun can play overtone high pitch 5, overtone high pitch 6 and overtone high pitch 7, and the range of the Xun is one third more than two octaves; the Xun-holed wind instrument can play overtone high pitch 5, overtone high pitch 6, overtone high pitch 7 and overtone high pitch 7, and has a range of one quarter tone more than two octaves.

2. a using method of a wide-range Xun comprises the following steps: pressing a finger hole III, a finger hole II, a finger hole I, a finger hole IV and a finger hole ten corresponding to the left-hand finger shape, wherein the finger hole ten corresponds to the left-hand thumb; simultaneously pressing a finger hole nine, a finger hole eight, a finger hole seven, a finger hole six and a finger hole five corresponding to the right finger type, wherein the finger hole nine corresponds to the thumb of the right hand; when more than two octaves need to be played, opening finger hole two, finger hole three, finger hole four, finger hole six and finger hole seven to blow, and playing harmonic high lift 5; opening finger hole two, finger hole three, finger hole four, finger hole five, finger hole six, finger hole seven, finger hole eight and finger hole nine, and performing half-hole ultra-blowing to play overtone high pitch 6; opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V, finger hole VI, finger hole VII, finger hole eight, finger hole nine and finger hole Ten-half-hole ultra-blowing to play the harmonic high pitch drop 7; when the overlapped tones of the small third-degree tones are played, the real-tone high tone 3 can be played by opening the first finger hole, the second finger hole, the third finger hole, the fourth finger hole, the fifth finger hole, the sixth finger hole, the seventh finger hole, the ninth finger hole and the tenth finger hole; opening a finger hole I, a finger hole II, a finger hole III, a finger hole IV, a finger hole V, a finger hole VI, a finger hole VII, a finger hole VIII and a finger hole Ten to play so as to play the real-tone treble 4; the finger hole is completely blocked and blown to play a harmonic high pitch 3; the harmonic high pitch 4 can be played by opening the finger hole eight-stage ultrasonic blowing. The design makes the range of the Xun to have one more minor third degree than two octaves and one more overlapped minor third degree.

3. A using method of a wide-range Xun comprises the following steps: pressing a finger hole III, a finger hole II, a finger hole I, a finger hole IV and a finger hole ten corresponding to the left-hand finger shape, wherein the finger hole ten corresponds to the left-hand thumb; simultaneously pressing a finger hole nine, a finger hole eight, a finger hole seven, a finger hole six and a finger hole five corresponding to the right finger type, wherein the finger hole nine corresponds to the thumb of the right hand; when more than two octaves need to be played, opening finger hole four, finger hole six, finger hole seven and finger hole eight ultra-blow to play overtone high pitch 5; opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V, finger hole VI, finger hole VII, finger hole VIII and finger hole JiuSUPERBLOW to play overtone high pitch 6; opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V, finger hole VI, finger hole VII, finger hole eight, finger hole nine and finger hole Ten-half-hole ultra-blowing to play the harmonic high pitch drop 7; when overlapped tones of a small second degree are played, a first finger hole, a second finger hole, a third finger hole, a fourth finger hole, a fifth finger hole, a sixth finger hole, a seventh finger hole, an eighth finger hole, a ninth finger hole and a tenth finger hole are opened to play real-tone high tones 3; the finger hole is full-blocked and ultra-blown, and the harmonic height 3 can be played. The design makes the range of the Xun to have one more minor third degree than two octaves and one more overlapped minor second degree.

4. A using method of a wide-range Xun comprises the following steps: pressing a finger hole III, a finger hole II, a finger hole I, a finger hole IV and a finger hole ten corresponding to the left-hand finger shape, wherein the finger hole ten corresponds to the left-hand thumb; simultaneously pressing a finger hole nine, a finger hole eight, a finger hole seven, a finger hole six and a finger hole five corresponding to the right finger type, wherein the finger hole nine corresponds to the thumb of the right hand; when more than two octaves need to be played, opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V and finger hole eight ultra-blow to play overtone high tone 5; opening a finger hole I, a finger hole II, a finger hole III, a finger hole IV, a finger hole V, a finger hole VI, a finger hole VII, a finger hole eight and a finger hole nine, and performing half-hole ultra-blowing to play a harmonic high pitch 6; and opening finger hole I, finger hole II, finger hole III, finger hole IV, finger hole V, finger hole VI, finger hole VII, finger hole eight, finger hole nine and finger hole Ten and half holes for ultra-blowing to play the harmonic high pitch drop 7. The design makes the range of the Xun more than two octaves by a small third.

5. a using method of a wide-range Xun comprises the following steps: pressing a finger hole III, a finger hole II, a finger hole I, a finger hole IV and a finger hole ten corresponding to the left-hand finger shape, wherein the finger hole ten corresponds to the left-hand thumb; simultaneously pressing a finger hole nine, a finger hole eight, a finger hole seven, a finger hole six and a finger hole five corresponding to the right finger type, wherein the finger hole nine corresponds to the thumb of the right hand; when more than two octaves need to be played, the finger hole is opened to perform octave super-blowing, and the overtone high tone 5 can be played; opening the four and eight ultra-blow finger holes to play the overtone high pitch 6; opening finger hole two, finger hole three, finger hole four, finger hole six, finger hole seven and finger hole eight ultra-blow, and playing overtone high pitch drop 7; and opening finger hole two, finger hole three, finger hole four, finger hole six, finger hole seven, finger hole eight, finger hole nine and finger hole ten and half holes to blow out, and playing the overtone high pitch 7. The design makes the range of the Xun more than two octaves by a small four-degree tone.

drawings

Fig. 1 is a perspective view of a first embodiment of the present invention.

Fig. 2 is a front view of the first embodiment of the present invention.

Fig. 3 is a rear view of the first embodiment of the present invention.

Fig. 4 is a flow dynamics diagram according to a first embodiment of the present invention.

fig. 5 is a perspective view of a second embodiment of the present invention.

fig. 6 is a front view of a second embodiment of the present invention.

fig. 7 is a perspective view of a third embodiment of the present invention.

Fig. 8 is a front view of a third embodiment of the present invention.

Fig. 9 is a perspective view of a fourth embodiment of the present invention.

Fig. 10 is a front view of a fourth embodiment of the present invention.

Detailed Description

the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Description of the drawings: it is obvious that the invention is primarily intended to provide a conception, and that all details of technical features may not be fully elaborated, and that no disclosure is given that is within the knowledge and height of a person skilled in the art.