4ths 5ths Octaves – Ear Training Chord 1 2 In this lesson, you will hear a 4th, 5th, or Octave played as a chord (diad) and then try to name it. Here is one example of each. Please press the Exercise button below. March 13, 2013 1 2 In this lesson, you will hear a 4th, 5th, or Octave played as a chord (diad) and then try to name it. Here is one example of each. Please press the Exercise button below.