The strings are different. The reason why the pickup position of Yipu organ bridge is different is that the vibration amplitude of strings in different positions is different when plucking strings. Because the vibration amplitude of the string near the center of the string is greater than that of the string near the bridge, this difference not only leads to great differences in the volume and timbre of the sound when plucking the string at different positions, but also the final volume and timbre when plucking the string at different positions.