Perfect 4ths Playing by Ear – Chord 1 2 In this lesson, you will hear a Perfect 4th played as harmonically as a chord, then play it by ear. Here is an example of a Perfect 4th played as a chord. Perfect 4th - Chord January 1, 2013 1 2 In this lesson, you will hear a Perfect 4th played as harmonically as a chord, then play it by ear. Here is an example of a Perfect 4th played as a chord. Perfect 4th – Chord Please press the Exercise button below.