The invention relates to a four-string viola, comprising: a viola structure, including a
headstock, a body, a string
system, a bow and four strings, the bow includes a bow rod, a bow point, a bow hair, Bow wood and accessory pendants; the string
system includes pegs, tailpieces and bridges, the pegs are four
hardwood pegs in a conical shape, set at the
headstock position, and passed through the tapered pegs on the side of the peg box holes are fixed; the four strings are respectively wrapped around the four
hardwood pegs of the peg, and the string board is arranged at the
tail position; the bridge is a piece of wood made of
maple, used to support the Four strings, the thickness, material, shape and position of the bridge will affect the tone of the viola structure; the electronic eye capture device is set on the
headstock of the viola structure, and is used to capture the viola body
Processing, to obtain and output the corresponding
piano sound capture image. Through the invention, the performance of the viola is improved.