Most capable singers who are at least familiar with harmony are quite capable of finding the 3rd (Major third off the melody line). The problem, however, arises when they stick TOO closely to the 3rd – or what’s called a “parallel (3rd) harmony”. Parallel harmonies (3rd’s) that never stray from the 3rd can REALLY mess up your harmony presence, as the 3rd will often force the harmony into awkward compound intervals (octave + interval), Maj 7ths, b9ths, and sometimes Major 6ths. This temporarily forces the harmony into the sporadic “jazz” chord – which would sound great with a jazz piece, but has very little use in traditional chord progressions.
In order to avoid stepping on others’ harmony lines and drifting to awkward jazz chords, consider arranging harmony lines for at least one of your singers that closely follow “oblique” motion – or motion of one harmony line that remains on the same pitch.: *Fig.A
*Fig A – Oblique Motion
If, for instance, you have two very capable harmony singers backing the melody line, establish the central interval of the melody (does the melody center around the root? The 5th?), then position one harmony on one or more of the “non-central” intervals.
Now HERE’S where the magic happens! Take, for instance, “Man of Sorrows”[C]. If we look at the verses, we can see that the melody centers around the 3rd and 5th . In arranging your oblique harmony, you would look at the pitch that remains most consistent in the C, F, Am, and G chords. C (CEG), F (FAC), Am (ACE) and G (GBD). From this, we can deduce that the pitch most common to the chords as a whole would be the “C”. In the key of “G”, however, we would alter the oblique line – only SLIGHTLY (also related to “similar motion” which we’ll cover in another article) – so the singer would shift to the pitch to the closest note from that “C” – which in this example would either be the “B” or the “D”. How do we determine which one to go to? Let’s ask the melody on the “G” chord! The melody is singing a “D” on “Betrayed”. Therefore, our oblique line would drop ½ step to a “B” so not to walk on the melody line! Beautiful! So, crafting the oblique harmony centered around “C” would look like this: *Fig.B
*Fig B – Oblique association
The beauty of the oblique harmony is that it provides harmonic stability. When one or more of our harmony parts are planted firmly in an oblique harmony, there may be incidental doubling with the melody, but not frequently enough to “walk on” the melody. The key, however, to seasoning your harmony with oblique motion is to find that “common pitch” relative to your chord progression!