Unit 1 · 3 lessons
Intervals
Measuring the distance between two notes by size and quality. Every chord and scale rests on this.
Goal of this unit
Name any interval from its spelling, and invert it.
Prerequisites
Lessons
- 1
Interval Size and Quality
about 15 minEvery interval name has two parts. The number comes from counting letters, the quality from counting half steps. Once that two-stage system is clear, it becomes obvious why an augmented 4th and a diminished 5th are different intervals despite both spanning six half steps.
Tools used in this lesson: Interval Calculator
- 2
Inverted and Compound Intervals
about 13 minFlip an interval upside down and the two numbers always sum to nine, while major swaps with minor and augmented with diminished. There is a reason for that rule, and it also explains why perfect intervals are called perfect. Compound intervals beyond the octave round out the lesson.
Tools used in this lesson: Interval Calculator
- 3
Consonance and Dissonance
about 14 minConsonance is not a matter of taste. It tracks the simplicity of frequency ratios. This lesson covers the three-way classification, the historical reason the perfect 4th sits awkwardly between categories, and how the demand for resolution created by dissonance is what drives harmony forward.
Tools used in this lesson: Interval Calculator / Ear Training