即“中音二胡”。其外形、构造、弓法、指法以及把位等,与二胡同。用丝弦时,里弦用老弦,外弦用中弦。现今常用金属弦。定弦比二胡低一个纯五度,定为g与d1或低一个纯四度,定为a与e1,采用五度定弦法。音域可达两个八度。音色具有广阔、饱满和沉厚的特点。由于中胡弦较长,指别距较大,演奏时难度较大,速度不宜过快。 That is, “alto erhu ”. Its shape, structure, bowing, fingering and the place, and the same with the second. When using a string, the string with the old string, string with strings. Today commonly used metal strings. Set a lower than a pure five-degree erhu, as g and d1 or lower a pure four degrees, as a and e1, using the five-degree fixed-chord method. The range is up to two octaves. Tone has a broad, full and deep features. As a result of a long string of peonies, which means a little apart from each other, the performance is more difficult and the speed should not be too fast.