Good question. Apparently the ghostly music is created by the movement and vibration of perfectly clean and uniform sand particles, which are normally found in remote locales.

• 问得好。显然，这奇妙的声音是由完全洁净而圆融的沙粒的运动和震动引起的，而这样的沙粒通常都处在偏僻边远的地区。