Perfect 4ths Playing by Ear – Down 1 2 In this lesson, you will hear a Perfect 4th played downward, then play it by ear. Here are some examples of Perfect 4ths going down.January 1, 2013 1 2 In this lesson, you will hear a Perfect 4th played downward, then play it by ear. Here are some examples of Perfect 4ths going down. Perfect 4th – Down Old McDonald Please press the Exercise button below.