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

say that each interval is the inversion of the other
     

SOUND COLORS
    Each interval has a distinctive sound. And because music can express emotions, it's possible to describe the sounds of intervals in words. While there's not a complete consensus among listeners, many people would subscribe to some or all of the following descriptions:

    In classical music theory, intervals are also classified as consonant or dissonant. A dissonant interval is one that is harsh-sounding or unsettled. A consonant interval is felt to be solid and stable. The classification of intervals as consonant or dissonant has changed over the centuries, however. In the Medieval and Renaissance periods, it was felt that the only consonant intervals were the unison, perfect 5th, and octave. Major and minor 3rds and 6ths were felt to be dissonant. Music from this period is full of 3rds and 6ths, but the final cadence (the end of the piece) typically ends with a chord consisting only of octaves and perfect 5ths, because composers felt that this ending was necessary in order to resolve the dissonances into consonances.
    In the Baroque and Classical periods (roughly 1600-1820), listeners became comfortable accepting the major 3rd as a consonance, but the minor 3rd was still felt to be somewhat dissonant. As a result, pieces written in minor keys often ended in a major key, so that the 3rd of the final chord would be major, not minor. By the Romantic period (1820-1920), ending a piece with a minor chord had become more acceptable.
    Due to harmonic developments in the 20th century, including both jazz and atonal classical music, the old distinction between consonant and dissonant intervals has largely evaporated. The only intervals that are still felt as dissonant by most listeners are the minor 2nd, the minor 9th, and, to a lesser extent, the major 2nd. The tritone, which was so disturbing to Renaissance musicians that they called it diabolus in musica (the Devil in music) is a consonant interval in jazz: Many jazz songs use a dominant 7th chord, which includes the tritone as the 3rd and 7th of the chord, as the tonic. And the major 7th is the characteristic interval in a major 7th chord, which is used as the tonic in just about all sweet-sounding jazz ballads. (For a full explanation of the intervals in these chords, see Chapter Five.)
    In general, musical dissonances resolve into consonances. That is, one or more of the voices in a dissonant chord moves upward or downward, usually by a whole-step or half-step, to create a new chord that is consonant. The dissonant chord adds tension to the music, and the resolution of the dissonance into a consonance provides a release of the tension. It's not the case that all chord-based music includes dissonances, or that all dissonances resolve into consonances, but the resolution of dissonance into consonance is certainly central to the language of harmony.
    Since we haven't yet explained what makes a chord dissonant, providing an example at this stage is difficult - but not impossible. Figure 2-12, which you may recognize, shows a dissonant interval (a major 2nd) resolving to a consonant interval (a minor 3rd). The resolution is produced by moving one of the notes of the dissonant interval down by a half-step.

    Figure 2-12. The dissonant interval in bar 1 (a major 2nd) resolves to a consonant interval (a minor 3rd) in bar 2.
     

HOW TO HEAR INTERVALS
    Learning to discriminate between the sounds of intervals takes practice. Fortunately, there are some mnemonic aids that will make it a little easier.
    First, if you're hearing an interval in which both notes are being sounded at the same time, you may find it helpful to mentally break it up into a melodic interval. Imagine that you're hearing the lower note first, followed by the upper note. While practicing this technique, you may want to sing the two notes out loud. Listen to make sure your first note matches the lower note of the interval, and that your second note