The_Complete_Idiot%27s_Guide_To_Music_Theory

Avoid big leaps.
Avoid Dissonant Intervals—Unless They Resolve
In this case we’re talking about the intervals between different voices—and this
is as much a practical consideration as anything else. If you’re fitting voices to
chords, you probably won’t have much in the way of dissonance to work with;
there’s nothing dissonant within an F Major chord, for example.
But what if you’re harmonizing an F Major seventh chord—in which two of the
notes are E and F, which are just a minor second apart? The voicing you want
to avoid is putting the two notes together on two close voices; for example, having
the first soprano sing the F and the second soprano sing the adjacent E. Not
only will this sound harsh; it will also be difficult for each voice to sing—the
notes are too close together. A better approach would be to put one of the notes
in a lower voice, so that there’s an octave or so space between the two notes.
Avoid unresolved dissonances.
The tritone is another interval to avoid in your harmony. This is simply the
hardest interval in the world to sing, or for instruments to hit. When you put a
tritone in your harmony, you’re just asking for trouble—specifically, for one of
the voices to miss the note!
Now, it’s okay to introduce this kind of dissonance, if you then resolve it. That
means you can include dissonance in passing tones, or even at the end of phrases,
but only if one of the voices then resolves to a more pleasing interval. For
example, in that F Major seventh chord, the voice with the E might quickly
resolve to either an F or a C. In the tritone example, you can move one of the
voices up or down a step to create either a perfect fifth or a third.
Chapter 15: Harmony and Counterpoint
199
Tip
For some good
examples of close
harmony, listen to
some old Beach
Boys albums. Of particular
note is the classic Pet
Sounds album, which contains
some terrific close
harmony on songs like
“God Only Knows” and
“Wouldn’t It Be Nice.”