Where the violin in Legend of Zelda wind waker?

Answer 1

There is no violin in that Zelda game. Unless you mean the one that Makar has, YOU can't obtain it but you find him in the forest haven behind the waterfall, (you use your grappling hook to get in there) play the earth Gods lyric, then take him to the earth Temple.

Answer 2

The korok with the violin is Makar. He is in Forest Haven inside the waterfall.