The erhu generally uses overtones to tune the strings. The specific method is: press the little finger of the left hand at 1/2 of the string length (referring to the line segment between the daughter and the Qin horse), and then use the bow to play the outer string sound, and then move the little finger frivolously. At the same time, a pure and transparent outer string high octave similar to the sound of a bamboo flute will be obtained. It forms a strong color contrast with the thick and round outer string. When the bow is fully drawn on the outer string, The bow hair turns to rub the inner string again. At this time, the little finger is off the string, and the index finger is frivolous at 1/3 of the whole string. The sound of the piano is slightly less than the octave overtone at 1/2 of the outer string. If the fifths of the inner and outer strings are aligned, the overtone pitches of the two places should be exactly equal; if there is still a pitch deviation between them, it means that the accuracy of the fifth is not enough. If we do not seek absolute pitch, but only relative pitch, we can use the overtone pitch of any string as the "reference pitch", and then adjust the overtone pitch at the specified position of the other string to the same height.
When practicing overtones for the first time, the overtone effect of the 1/3 of the inner string is likely not as good as that of the 1/2 of the outer string. This may be because the strength of the inner string to push the bow is not as easy to control as it is to draw the bow. You can try it by changing the method. When you practice overtones for the first time, there will be an irritating and harsh "killing chickens and ducks" sound, which may be caused by three reasons: one is the uneven force of the bow hair rubbing the string, the second is the wrong position of the string (ie the overtone point), and the third It refers to the real pressing that is used when the finger touches the string. Efforts to improve from these three aspects, it is possible to emit transparent and clear overtones.
In addition to using overtones to calibrate the tune of the erhu, other fixed-pitch instruments can also be used to help tune the erhu. For example, piano, harmonica, flute, tone flute, tuning fork, etc. can be used for tuning, but the selection of these instruments for tuning must be based on the sound performance of the erhu instrument. Too high or too low will affect the performance. If it is too high, the tension of the strings will cause the pressure on the skin to exceed the specified limit, and the vibration will be extremely uncoordinated, which will lead to dry and monotonous pronunciation, and will greatly shorten the service life of the strings and skins; if it is set too low, the Because the strings are too loose, the resonance effect of the piano skin is poor, resulting in obscure and dull pronunciation. At the same time, the strings lose the necessary tension, so that the fingers lack the corresponding reaction force when they touch the strings, and the pitch is not easy to control.