S=Sound[{SoundNote["C", .5], SoundNote[{"A", "F"}, .5],
  SoundNote[{"A", "F"}, .5], SoundNote[{"A", "F"}, .5],
  SoundNote[{"A", "F"}, .5], SoundNote[{"A", "F"}, .5],
  SoundNote[{"A", "F"}], SoundNote[{"G", "Bflat"}, .5],
  SoundNote[{"A", "F"}, .4], SoundNote["Aflat", .1],
  SoundNote[{"A", -3}], SoundNote["G", .5],
  SoundNote[{-7, -3, "F"}, 1.5] , SoundNote["E", .3],
  SoundNote["F", .2], SoundNote[14, .5],
  SoundNote[{"Bflat", 14}, .5], SoundNote[{14}, .5],
  SoundNote[{"Bflat", 14}, .5], SoundNote[{14}, .4],
  SoundNote[13, .1], SoundNote[{"Bflat", 14}], SoundNote[15, .5],
  SoundNote[{"Bflat", 14}, .5], SoundNote[{"Bflat", 14}],
  SoundNote[{"C", 12}, .5], SoundNote[{-2, "Bflat", "D", "F"}, 1.5]}]
Export["allen_yang.midi",S, "Midi"]