He says the fiddle players will pull the sound post back a little bit.

他说小提琴手会把音柱往后拉一点。

They'll pull the sound post back a little bit to get more of the " wangy" sound, and they'll use a harder, a more steel-type string.

他们会将音柱向后拉一点以获得更多的“wangy”声音，并且他们会使用更硬、更钢质的琴弦。

The " sound post" is the part of the violin that's inside the violin that helps produce the sound that a violin makes when you play the strings.

“音柱”是小提琴内部的小提琴部分，有助于产生小提琴在您弹奏琴弦时发出的声音。