Erhu belongs to the national stringed musical instrument. Its pronunciation is characterized by the back and forth movement of the bow. The friction between the bow hair (horsetail) and the strings causes the strings to vibrate. Due to the structure and pronunciation characteristics of the erhu, the dynamic mode of the erhu in the performance is determined.

1. Vibration characteristics of erhu strings

According to the physical properties of the vibration of the object, the vibration generated when a string is instigated by an external force is called forced vibration; due to its own elastic relationship, the string can continue to vibrate after the external force is removed (due to the internal action of the string). vibration) is called natural vibration. Only when these two vibrations resonate (when the amplitude is the largest), the sound of the strings is pure and beautiful.

The vibration of huqin strings must meet two conditions: the pressure of the bow hair (horsetail) on the strings and the movement of the bow. These two conditions must be met at the same time for the strings to sound. Therefore, the strength problem in erhu performance is to achieve the needs of different artistic expressions by changing the tension of the strings and the friction between the bow hair (horsetail) and the strings.

1. Different manifestations of the tension change of the strings in the left and right hands

There are two factors to change the tension of the strings in erhu performance, which are determined according to the different “operation” forms of the left and right hands, that is, the acupressure of the fingers of the left hand and the effect of the bow hair (horsetail) on the strings when the bow is bowed with the right hand. pressure. When the fingers of the left hand press the strings, the pressure of the fingers on the strings causes the strings to change the tension more or less. tension, and thus changes in strength. In addition, when the left hand changes the handle, especially the "jump handle", the swing force generated by the movement of the left arm up and down (especially the displacement from the low handle to the high handle position) is transmitted from the arm to the finger knuckles and acts on the strings. This kind of "swing force" can also produce a certain amount of force.

The pressure of the bow hair (horsetail) on the strings is mentioned above, which mainly refers to the control of the strength of the right hand bowing. To make the bow hair (horsetail) change the pressure on the strings, it is necessary to properly adjust the right fingers on the bow rod and bow hair. The degree of "tightness" of the "tightness", in doing so, must also concentrate the strength of the entire right hand on the index finger, middle finger and ring finger.

2. Friction between bow hair (horsetail) and strings

Bowing with the right hand creates friction between the bow hair (horsetail) and the strings. Of course, this friction is due to the bonding effect of "rosin". The size of the friction force is related to the pressure between the bow hair and the strings on the one hand, and the speed of the bow on the other hand. Only the combination of the two can change the friction force between the bow hair and the strings, so that the playing strength can be improved. Change. When the bow is drawn, the difference between the bow and the bow, and the difference between the outer string and the inner string will also produce different strengths. Generally speaking, it is easy to achieve a greater force when drawing the bow, but it is not easy to do it when pushing the bow. From the perspective of the bow segment, due to factors such as the way the right hand holds the bow and the habit of opening and closing the elbow and arm, whether it is drawing or pushing the bow, the root and middle part of the bow tend to increase the strength and friction, while the tip of the bow tends to increase the strength and friction. Parts tend to be weak and not prone to strong friction. As far as the two strings are concerned, pulling and pushing the inner string is easy to generate strength. At this time, the middle finger and ring finger of the right hand tend to "tighten" the bow hair and increase the friction; when pulling and pushing the outer string, the right hand can only "hold" the bow. To walk, at most the index finger presses down the bow to increase a little bit of force, and its strength is not as easy to control as when the inner string is used. The speed of the bow is also a very important factor in changing the strength. For example, at the moment of the "sound head" of the slow bow, the rapid "start" of the bow will produce explosive force, the strength will increase, and the sound will be full and solid.

2. Technical handling of dynamics in erhu performance

1. The strength of the slow bow

Playing the slow bow is the foundation of the erhu, but it is also a difficult technique to master. This is mainly a matter of strength control. A slow bow cannot achieve a certain strength by increasing the speed because it is "slow" (except for the "cap"). Erhu bows pay attention to "one line to go" as the saying goes: "you can draw a line, but not a large piece". The "one line" here means that the bow is required to be straight, otherwise it is rocked up and down ("a large piece").

According to common sense, the bow of the erhu should be the first one, which is more in line with the law of activity of physiological functions. But the author thinks: If you pursue the change of strength in slow bow performance, you can adjust the bow direction appropriately. The bow is tilted slightly downward when the bow is drawn, and the bow is tilted slightly upward when the bow is pushed.

When the bow is carried in this way, the right hand can generate a downward "gravity" whether it is pulling or pushing the bow, and this "gravity" increases the bow pressure (the pressure of the bow hair on the strings) and the bow hair of the right hand. friction with the strings. Such as the introduction to playing "Jianghe Shui":

1 B (3 7 strings)

3…6…2…5. 3 6…

In order to express a feeling of grief and indignation, the first three tones with decorative tones must have "sound heads" in order to produce a strong explosive force. The next tone adopts "jumping handle" and "pressing and kneading", which moves the sound area higher, produces tension, and achieves a strong artistic effect of "sorrow". In this introduction, the change of erhu performance is not only a powerful but also a hidden "internal" explosive force, and the performer should have a feeling of venting out the grievances and grievances that have been accumulated for a long time. The slow bow brought out powerfully by "Yin Tou" is like a wave after wave, and the mood is constantly rising. When playing, you can use the bowing method to increase the "gravity" downward to obtain a satisfactory sound effect.

In addition, the "segmented stumbling" of the bow is also an effective method to change the bow pressure and frictional force. The segmented stumbling keeps the bow in a cyclical "instant pause" state when it is running, so as to generate friction between the bow hair and the strings. Each point of force produces cadence. For example, the treatment of long sounds in "Erquan Yingyue":

1 D (1 5 string) 4/4

3.5 2.351 6235 | 1 --

1.6 1.233 21.1 6123 | 5 --

Another example is the fragment in "Autumn Moon in the Han Palace":

1 F (6 3 strings)

5.6 1 7 | 6.1 6 5 | 3.5 1 6 | 5. 16

6.1 5 6 | 3. 5 | 2 356 | 1. 7 | 1.

2. Vibration strength

Kneading strings, also known as "yin" and "猱", are all quoted from the performance of Guqin. Under normal circumstances, there are two ways to vibrate the erhu: one is to learn from the violin's vibrating method "rolling and kneading"; The former not only changes the tension of the string, but also changes a certain length of the string (the fingers move up and down slightly); the latter only changes the tension of the string. Of course, changing the tension of the strings and the method of vibrating the strings should be determined according to the style of the tune being played, such as playing "Autumn Moon in the Han Palace" (excerpt)

1 F (6 3 strings) 2/4 3/4

2. | 6 1. 6 | 16 5.5 61 | 5. 3 | 5.6 17 | 6.1 65 | 3.5 16 | 5 - -

Similar to this kind of classical music, most of them use the finger-shaking method, while some modern works use a larger range of "tumbling" and "crushing" methods, such as playing "The Wish of the People of Honghu Lake" (excerpt)

1 A (4 1 strings) 4/4

1. 6 5653 2 35 6 1 | 1 2 1612 4 -- |

4 -- 2.421 6.2316 | 5 -- -- -- |…

Another example is the slow section of "Turn Over Song":

1 D (1 5th string) 2/4

2 3.532 | 1. 6 | 2 2 5332 | 32 1. | 2776 5 2 | 5. 7|

6765 2 4 | 5. 6 | 1 1 6 | 5 3 2 1 | 2 2 76 | 5 - |

To sum up, the variation of the strength of erhu performance is largely determined by the way and method of bowing with the right hand, that is, the bow pressure and the friction between the bow hair and the strings plus the speed of the bow. Different strengths require different treatments. For example, when playing the strength of "pp", the right hand should move the bow stably, and the bow should be lightly attached to the piano barrel and walk slowly; when playing the strength of "ff" and "sf", the right fingers should be on the bow and the bow. The supporting force of the hair should be increased, resulting in great bow pressure and friction and so on. In addition, it is necessary to deal with the problem of strength, and it should not be neglected to use each bow segment reasonably to achieve the required strength.