http://jsfiddle.net/sunwangshu/9bvp37p0/15/
Two melodies play together, with different bpm 76 and 77.

var sampleURL = "http://scarlettsan.me/resources/Dream_high.mp3";
var sampleURL2 = "http://scarlettsan.me/resources/Dream_high_76.mp3";
var player = new Tone.Player(sampleURL).toMaster();
var player2 = new Tone.Player(sampleURL2).toMaster();
//trigger the start of the sample once its loaded
Tone.Buffer.on("load", function(){
player.loop = true;
player2.loop = true;
player.start();
player2.start();
});
I tried some different combinations, different piece with one octative difference. And I think the same piece play with itself works the best.
Realization of notes:
Wind part chord: http://jsfiddle.net/sunwangshu/43wfqha0/2/
Piano part: http://jsfiddle.net/sunwangshu/rbnxe9s6/