Intervals V
In this lesson we'll introduce the remaining basic intervals, (the Semitone, the Minor 6th and the Major 7th). As usual, we'll begin by adding their definitions to our existing list of intervals:
| Number of semitones | Abbreviation | Scale-degree / chord-tone | |
|---|---|---|---|
| Prime (unison) | 0 | P1 | 1 |
| Semitone | 1 | +1 / m2 | ♯1 / ♭2 |
| Major Second | 2 | M2 | 2 |
| Minor third | 3 | m3 | ♭3 |
| Major third | 4 | M3 | 3 |
| Perfect fourth | 5 | P4 | 4 |
| Tritone | 6 | TT / +4 / °5 | ♯4 / ♭5 |
| Perfect fifth | 7 | P5 | 5 |
| Minor Sixth | 8 | m6 | ♭6 |
| Major Sixth | 9 | M6 | 6 |
| Minor Seventh | 10 | m7 | ♭7 |
| Major Seventh | 11 | M7 | 7 |
| Octave | 12 | P8 or 8ve | 8 |
The Semitone
We already know, in essence, what a semitone is. But we haven't discussed it until now because, like the Tritone, it can exist in two forms:
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The Diatonic Semitone
or ‘Minor 2nd (‘m2’) is found in our traditional scales (Major, Minor etc.) and its corresponding scale-degree/chord-tone is ‘♭2’. The notes of a diatonic semitone always have different letter-names (e.g. F♯-G; D-E♭; B-C). -
The Chromatic Semitone
sometimes known as the Augmented Prime (‘+1’), isn't found in the traditional scales and has a corresponding scale-degree/chord-tone of ♯1 It always occurs between two notes notes with the same letter-name (e.g. A-A♯; D♭-D).
Although there's a two-string version of this shape with can be very useful, we'll stick with its single-string counterpart for now.
The Minor Sixth
This can be thought of as a Perfect 5th plus a Minor 2nd or as the complementary interval of the Major 3rd. Either way it spans 8 semitones. We'll consider two forms, a two-string shape:
... and one that covers three strings:
The Major Seventh
The last of our basic intervals, this is the complementary interval of the Minor 2nd and is equivalent to 11 semitones. We will only consider one form of this interval for now: