A Player's Guide to Chords and Harmony by Jim Aikin Read Free Book Online

these intervals are major, minor, augmented, and diminished. Being able to grasp the interval relationships within the scale is an important part of learning to use chords.
    To reiterate, the terms "3rd," "5th," "7th," and so forth can refer to three distinct things: They're the names of intervals, and they're also the names of notes within a particular scale or chord. In the latter case, the name indicates the interval that lies between the note and the root of the chord or the tonic of the scale - the nearest root or tonic below the note, to be a little more specific. For example, in an A scale, the 5th is E, because the interval from A up to E is a 5th.
    In some music theory texts, these two usages are formatted using different typography. You may see the names of pure intervals spelled out (as third, fourth, fifth, etc.), while the names of notes within a scale or chord are formatted as ordinal numerals (3rd, 4th, 5th, etc.). In this book, I've chosen to use numerals for both usages, on the theory that nobody but typographers and copyeditors pays much attention to the difference in formatting.

    Figure 2-6. Most of the examples earlier in this chapter use C as the lower note of the interval. Intervals can start on any note, however. Shown here are all of the intervals smaller than an octave that use the notes of the C major scale: 2nds (a), 3rds (b), 4ths (c), 5ths (d), 6ths (e), and 7ths (f). The type of each interval is shown. These interval relationships are the same in any major scale: For instance, if you start on the 2nd step of the scale and construct an interval of a 3rd, it will always be a minor 3rd.
     

MORE WAYS TO ALTER INTERVALS
    If you're the type of person who likes to break the rules once in a while, you may look at Figure 2-5 and find yourself wondering, "What would happen if I made an interval by putting an E6 next to an F#? What sort of interval would that be? Or what if I combine a G# with a B6?"
    These are real intervals. Useful ones, too. They even have names. When a major/minor-type interval (one based on a modal scale step) is stretched by an extra half-step, so that it's even bigger than a major, it's referred to as an augmented interval - the same term we've already met when talking about perfect (tonal) intervals that are enlarged by a half-step. Likewise, when a modal interval is narrowed by an extra half-step, it's called diminished.

    Thus there are not two types of 2nds, 3rds, 6ths, and 7ths, but four - diminished, minor, major, and augmented. And 4ths and 5ths can be either widened or narrowed, so there are actually three types of 4ths and 5ths - diminished, perfect, and augmented. The full panoply of possibilities is shown in Figure 2-7

    Figure 2-7. A more complete catalog of intervals, with a couple of examples of most types. Doubly augmented and doubly diminished intervals have been omitted from the examples, since they're rarely seen.

    In case you were wondering, there's no such thing as a diminished unison. Once in a great while, though, you'll run into a doubly augmented or doubly diminished interval. For instance, the interval from C# up to B6 is a diminished 7th, so the interval C#-B66 would be a doubly diminished 7th. Double flats (66) and double sharps (##) are sometimes needed when notating music in keys that have lots of flats or sharps in their key signature. The rules for when and how to use them are discussed in the section "Chromatic Spelling" in Chapter Seven.
    Calling the interval C#-E6 a diminished 3rd may seem needlessly academic and fussy. The interval consists of two half-steps - why not just call it a major 2nd? Well, you can call it that if you like. In the real world, it may not make a lot of practical difference. You'll still be able to communicate your ideas to other musicians. But later in this book, we'll see many chords that contain augmented and diminished intervals. An F7#5 chord, for instance, contains both C# and E6. Calling the interval a major 2nd