The_Complete_Idiot%27s_Guide_To_Music_Theory

When you put your two melodies together, you should make sure they both fit
within the notes of the underlying chord, and stay within the confines of the
underlying scale. The two melodies should also not duplicate each other; if you
have two identical melodies, you’re writing in unison; not in counterpoint. That
means each melody should have its own motion—which should complement,
but not interfere with, the motion of the other melody. The notes within each
melody also should not interfere or clash with the notes in the other melody;
avoid dissonant vertical intervals.
It’s okay for the two melodies to have their own rhythmic patterns. In fact, in
classical music it’s expected. (If your two melodies have identical rhythmic
structure you have what is called a 1:1 rhythmic ratio, which in some ways is
easier to work with than more rhythmically complex forms.)
Creating Your First Counterpoint
The best way to learn about counterpoint is to dive into the deep end—and
start composing!
For our first counterpoint, we’ll start by defining some parameters. These are
not necessarily hard-and-fast rules for the contrapuntal form, but they do make
it easier for beginners to create a working counterpoint.
Here are the parameters:
◆ Use a 1:1 rhythmic ratio; both melodies should use the same rhythmic
patterns.
◆ Only consonant harmonic intervals are allowed; no dissonant harmonies.
◆ The lower part must begin and end on the tonic of the key.
◆ The upper part must begin on either the first or the fifth of the key, and
end on the tonic—either in unison with the bass part or an octave above.
◆ Between the melodies, rely heavily on intervals of thirds and sixths. Avoid
octaves and unisons, except for the final note.
◆ Move each voice the shortest distance possible.
Now let’s get started.
Some composers like to write both melodic parts simultaneously; this enables
them to employ various advanced techniques, such as sharing a contrapuntal
melody between the two parts. However, for beginners it’s a lot easier to write
the first part first; then complete the puzzle by adding the second, counterpoint,
melody.
Which is exactly what we’ll do.
We’ll start from the bottom up and create our first melody for the lower voice.
(This is the staff labeled “2,” in bass clef.) Our melody is in 3/4 time, in the key
of F Major. Because counterpoint works best when both parts have a lot of
rhythmic and melodic movement, the melody is fairly lively, with a lot of eighth
notes; it also starts and ends on the tonic note, F.
Chapter 15: Harmony and Counterpoint
Note
These general principles
are similar to the ones
established by Johann
Joseph Fux in his classic
counterpoint book Gradus
ad Parnassum (“steps to
perfection”), published in
1725. Many great composers
throughout history
have used this book to
learn counterpoint.
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