How to find chords for a bebop line

Question

I created this melody and want chords to go over the melody being a bass line or just chords.

Answer 1

I'll answer the question, "how does one determine the harmony of a bebop line?" by offering some general techniques. Then I'll give some examples of these techniques using the piece above.

Here are the general techniques I recommend using:

1. Look at the notes occurring on strong beats (downbeats); check to see if these notes spell out a chord.
2. Look at the end of a measure for transitions to a new chord.
3. Look at measures 1, 5, 9, etc. (every four bars) where new chords are likely to appear.
4. Look for any part of the melody that would work over a II-V-I progression.
5. Look for common bebop harmonies (e.g., Bird Changes)
6. Write out several options when more than one possible chord exists.

Now I'll try to make these techniques a little more tangible by applying them to your melody, above.

Technique 1. The line in measure 1 seems to be outlining these notes: D F♯ C♯ A, which makes me think D maj for measure 1.

Technique 2. In measure 2, the fourth beat changes to a C♮. This makes me hear a D7 transition over beats 3 & 4 of measure 2, and this D7 transition makes me expect G maj (or maybe G7) in bar 3. (That doesn't necessarily mean measure 3 is actually G maj, of course.)

Technique 1. In measure 4, I see the lick very clearly outlining an A7 or A13 arpeggio: the first two notes of measure 4 are "surround tones" leading to C♯, the third tone of A13. The 7th through 12th notes of measure 4 very clearly spell out an A6 chord, and the G♮ (a crucial part of the A7 or A13 chord) is emphasized on both beat 2 and beat 4.

Technique 3. In measure 5, I tend to expect some sort of new chord (something besides D maj). The downbeats spell out B A A F♯, which is consistent with a B min chord. A B min chord would fit in your song's D maj tonality; in particular, B min is the minor vi chord of D maj. Moreover, when I next consider the whole line in measure 5, it seems like it highlights chord tones from B min.

Technique 6. In many cases, there will be some ambiguity--or at least, there will be two good chords that you have to choose between and which could both work well over a single set of notes. For example, the first two beats of measure 7 spell out an F♯ min triad. These two beats thus could be F♯ min, but they could also be D maj 7. In each case like this where there are two good choices, I would write out both possible chords, and then I would read through the song sequentially, starting at the beginning, trying to make choices that provide some overall cohesion or that provide some overarching similarity to a well-established bebop harmony.

Technique 4. When looking for II-V-I progressions, you can look for II-V progressions or V-I progressions. For example, when I say hear that D7 sound at the end of measure 2, this makes me expect G maj at the beginning of measure 3 because D7 - G maj is a V-I progression. As a second example of this technique, let's say you choose F♯ min for beats 1 and 2 of measure 7. I would immediately check to see if B7 works in beats 3 and 4 of measure 7, because the progression F♯ min - B7 is a ii-V progression.

As a final note, I recommend using these techniques in an iterative fashion (take a first pass, skip around to the measure with clear-cut chords, take a second pass, skip around again, etc.). It might be helpful to remember that there's not just one correct answer. You could even try harmonizing it a few different ways, listening to all of them, and choosing the one you like best. When I write harmonies this way, I usually expect to have slight changes in my original melody in order to better fit the underlying harmony/chords that I decide upon. Good luck!