The erhu belongs to the stringed musical instrument among the national musical instruments. It is produced by the friction of the bow on the strings, and the vibration is transmitted to the barrel through the skin of the piano. Therefore, the type of strings and the quality of the strings have a very important influence on the timbre of the erhu.

(1) Types of Erhu strings

There are two kinds of erhu strings: silk strings and metal strings. Metal strings are now commonly used. The quality of the string is related to the elastic capacity, tensile strength, density, molecular structure of the string material and the percentage value of the string tension and tensile strength at a certain vibration frequency. From the perspective of sound quality and acoustics, it largely depends on the overtones of the strings vibrating under certain tension conditions, that is, the number of overtones in the overtone column and the amplitude of each overtone. Generally speaking, if the amplitude of low-order overtones is large, the timbre will be round, rich and powerful; if the amplitude of medium and high-order overtones is large, the sound will be bright and penetrating.

(2) Tone characteristics and advantages and disadvantages

The timbre of the silk strings: The timbre is simple and straightforward, restrained and reserved, and contains a simple beauty. It feels very deep and flavorful. The tone of the silk strings tends to be simple and hoarse. It is very suitable for expressing traditional music. It has incomparable musical charm, making the expression of music more comfortable, relaxed and profound. It has a feeling of comfort and relaxation, which can make the player's mind achieve the effect of natural relaxation. Press your fingers gently, and you don't need to use too much wrist strength, not even to play. The volume is also lower, with less burden on the eardrum and less impact on the surrounding environment. Although low volume is not good for stage performances, for erhu players, many of them are not for stage performances. For the perspective of leisure and self-entertainment, the volume of silk strings will be more comfortable. Therefore, playing the erhu with silk strings is relatively easy, which can relax the body and achieve the highest state of natural unity with the comfort of the mind.

Disadvantages of silk strings: The silk strings themselves have poor stability against strong tension and are easy to run. The positional tones cannot be produced, there are many noises, and there are many wolf sounds, which cannot meet the needs of interpreting the current erhu music. The life of silk strings is short. The sensitivity of the silk strings is not as fast as the metal strings, and the fast music is dignified. In addition, some techniques such as fast bow, jumping bow, throwing bow, sling and pulling and so on cannot achieve the effect of metal strings.

The tone of the metal strings: sharp, tense. The tone of metal strings tends to be delicate and pure. The advantages of metal strings: good vibration, strings that will not rust are generally stainless steel, and the vibration of stainless steel is good without steel wires. The service life is relatively long, and it is suitable for high-skilled, more enthusiastic, cheerful and bright songs. In terms of volume, it is also more suitable for stage performances.

Disadvantages of steel strings: higher hardness, more tense fingers, and more wrist strength when playing.

(3) Works suitable for performance

Silk strings are great for performing traditional tunes. For example, there are some transpositions in "Autumn Moon in the Han Palace", which can be easily and freely imagined, which is absolutely impossible for metal strings in traditional repertoires. There are also performances such as stop and slide, and the silk strings feel particularly deep and charming. Elegance and quietness are like "Flower Joy" by Sizhu in the south of the Yangtze River, emotional and passionate like Hua Yanjun's "Erquan Reflecting the Moon", "Listening to the Pine" and Sun Wenming's "Flowing Waves", and homesickness is expressed like Lu Xiutang's "Nostalgic Journey" Etc., are all facial expressions that are very suitable for playing with silk strings.

Metal strings are suitable for expressing more technical and passionate songs, such as "Horse Racing" by Mr. Huang Haihuai, "The Galloping Horse" by Mr. Chen Yaoxing, and "Sanmenxia Imagination" by Mr. Liu Wenjin. Another grand scene.

I personally think that although metal strings are widely spread now, silk strings have unique characteristics that metal strings cannot replace. Its tone is simple and straightforward, the inner sword is subtle, and it has the subtle, graceful and elegant heritage that Chinese literati likes. This characteristic is particularly expressive for repertoires featuring elegance and quietness, lingering sadness, passion, and homesickness.