Three intervals now. The fourth, the fifth and the major third. In the numbers, a major third is four. An octave is zero, or twelve if you'd rather.

The drills go fast on purpose. I play an interval, you guess the two notes, then I arpeggiate it and play it again. There's no time to dig into the sound the way you did in Unit 1. You guess anyway. After a few days in a row the guesses start landing, and that's the training working.

Second inversion triads come back with a different job. Listen for the middle note. That's the root. Tell me whether the chord is one, four or five.

Then major or augmented. Then root or second. Then a major third above or below a note, sung by letter name, faster than feels comfortable.

C major to C flat again, one key per lesson. The number progressions get a second label. You already say cadential six four. Now you'll say pedal six four when the bass holds still and the chord above it moves to four and back. Everything else is one, four, five and the numbers.

Bird song and rain sit under the tracks. Attention restoration theory again. Focus through it.

Before the final, go back through any lesson that gave you trouble. Once each, no more. Then stop for the day.

The final exam is in three parts. Root or second inversion. Fourth, third or fifth at speed. Then chord progressions. One mistake per part to pass, and a part you fail waits for the next day. Pass all three and you're ready for Unit 5.

It won't give you the minor third. Major thirds only, so every triad you hear is major or augmented. Minor comes later, once the major third has settled.

It won't give you time. The interval drills move quicker than you'll like. That's the point, and it stays that way.

It won't go easy in Lesson 1. I push hard on the first day and ease off in later lessons. Don't read a bad first score as a verdict.

If you skipped Unit 3, don't start here. The second inversion sound and the cadential six four are assumed.