||The Gaohu and the Zhonghu are common doubles for Erhu players.
The Gaohu is higher pitched and the Zhonghu is the alto version.
This instrument first appears after 1104 in the Song Dynasty. The Gaohu
is particularly used in Southern China. Traditionally a Gaohu had two
silk strings, but today metal strings or a combination of metal/silk strings
are more common.
The physical structure of a Gaohu is similar to that of an erhu, although
the neck of this instrument is shorter. The tuning is a fourth to a fifth
higher than the erhu, giving it a higher pitch voice. Because of its mellow
tone quality, the Gaohu is chiefly used in Cantonese music. It can be
used as a solo instrument normally for lively and merry music pieces.