*Music Theory*

*WebCourse*

## Lesson 10 |

With this, our tenth lesson, we return to a very important topic: musical intervals. An interval is the distance between pitches measured in half steps and whole steps. Since tones can appear simultaneously (harmonically) or successively (melodically), there are harmonic and melodic intervals, but they are measured in the same manner. There are two identifying features of every interval: size and quality. Let's begin with interval size. The number of note names needed to count from one pitch to another is called the ordinal number. Therefore, the ordinal number for the interval C/E is three, since we count from C, through D, to E. Two notes with the same pitch name on the same line or space is called a unison or prime. Two notes with the same pitch name separated by all the other pitch names is called an octave. Here is a list of harmonic intervals from the prime to the double octave (the fifteenth) with ordinal numbers written below them.

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*© Copyright 2005 *

*Mark McFarland *