Erhu is a stringed instrument. There are two strings. The modern erhu is set with a pure fifth degree, which belongs to the middle and high range of the huqin. Luthiers usually use wood to make erhus, and some luthiers use ivory, jade, plastic and other materials to make erhus because they have considerations other than acoustics. One end of the piano tube is covered with snake skin, which is the source of the unique sound of the erhu. Some advanced erhus use python skin. The timbre of erhu produced in different places is different. Traditionally, the erhu produced in Shanghai has a softer tone; the erhu produced in Beijing has a higher-pitched tone; the erhu produced in Suzhou has a mellow tone that combines the characteristics of Shanghai and Beijing.
