Today I would like to talk with you about why D-A is used for erhu tuning? The following analysis is my opinion, and I hope to discuss it with you.

1. Relationship with singing

The earliest and most direct way for humans to express music is singing, because human vocal cords are innate, unlike musical instruments, which need to be invented and developed. Among all the musical instruments, the erhu is the most singing and the musical instrument closest to the vocal range. For example, flute and suona are high-octave instruments, and all plucked music has a wide range, exceeding the range of human voice. We can make a comparison between the range of modern songwriting and folk songs and the range of erhu. For example, "Into a New Era", "Embroidered Pouch (Shanxi Folk Song)", "Jianghe Water (Northeast Folk Song)", "The Moon of the 15th", "Good Day", etc., the lowest note is d, which is the same as the lowest note of Erhu . I checked and found that in modern songwriting, more than 95% of the songs have the lowest note of d, which is the lowest note of the erhu. The best treble area of the human voice is to the treble a, that is, the higher octave of the outer string of the erhu, which happens to be the best and most expressive area of the erhu. From this point of view, the tuning of the erhu and the vocal range should be closely related.

2. Relationship with mode

Chinese music belongs to the category of modal music. Any of the notes in our pentatonic scale can be used as a mode dwell, thus forming five modes of Gong (1), Shang (2), Jiao (3), Lu (5), and Yu (6). And the tonic of these five modes happens to be the lowest of the erhu. We also cite the five songs above as examples. "Into the New Era" is in the key of D, the palace mode (1 is the main tone), and the lowest tone is d. "Embroidered Purse" is in the key of C, which is a Shang mode (2 is the main tone), and Shang is d when C is the palace. "Jianghe Shui" is in the key of B flat, and the angular mode (3 is the main tone), and the angle of B flat is d. "The Moon of the Fifteenth" is in the Kuo mode (5 is the main tone), G is the palace, and the Kuo is d. "Good Days" is in the Yu mode, and the Yu in the F palace is d. It seems very complicated to say that, you can understand these songs with the erhu, and there will never be a situation where the vocal range is not enough. And the highest treble is on a. The lowest note is all d. This is the reason why the erhu is tuned to d-a.

3. Tonal reasons

Erhu sets d-a, which can ensure that there are two open strings, d and a, when playing the five keys of B flat, F, C, G, D and A. Suppose the erhu tuning is c-g, then the B-flat is 2-6 strings, F is 5-2 strings, C is 1-5 strings, G is 4-1 strings, and D is 7-flat. The 4th string, the key of A becomes a flat 3-7 string. The two sharp tones of G and D are the most frequently used keys in Chinese music, but the erhu has to be played in cut, and it is unimaginable that there are no open strings.

There is a musical instrument that can be used as circumstantial evidence, that is, the guzheng. The tuning of the guzheng is four octaves of D-d, which can also guarantee that when playing the five keys of B flat, F, C, G, D and A, there are two empty strings, d and a. The two open strings do not need to be tuned in the five keys above. If there are E-flat and E-flat keys, it will not work. Two open strings, d and a, must be moved. Therefore, there are no keys with three flats or more than four sharps in traditional zheng music.

Erhu does not need to be tuned, but it needs to be played with cut handles. Without the sound of the empty strings, the technical difficulty is increased, and the taste of playing tonal music is far worse.

4. Other reasons

For the above reasons, in fact, in ancient China, the key of D was used as the key of the palace, which is a different concept from the key of C in Western pianos, which is the key of no black key. As we all know, Kunqu Opera is in the key of D, so the D-tuned flute that accompanies Kunqu Opera is the Zhenggong flute, the first of the flute family. And the current translation of the noun called by the Zhenggong is to use D as 1, and it is the emperor's boss among all 1s, and this D happens to be the 1 and the innermost string and the empty string of the erhu D key.