For a given chord, the chord tones are composed via going 3rd, like a C Major is a {Major 3rd, Minor 3rd}
or a C Minor is {Minor 3rd, Major 3rd}
. The 7th, 9th, 11th, and etc... are also created via stacking 3rds.
It seems to me that going with 3rds, up or down, can't go wrong.
When I tried to write a harmony line for a vocal melodic line, I noticed that if I go 3rd intervals up, the melody remains intact. It is recognizable to most people. It just becomes fatter and warmer in tone.
However, if I go 3rd intervals down, the melody becomes different. It just doesn't sound like the original melody anymore.
Here's a concrete example, this is Ode to Joy in C (not sure if it is 100% correct, just did it from memory)
The melody is recognizable, it didn't change the quality of the original song. However when I do the opposite, instead of harmonizing E with G, I harmonized it with C (3rd interval down), the quality changed! It sounded like the harmony hijacked the melody.
Here's my problem. I have a female singer who sings the melody. I want to add a male voice to it to thicken the tone. The male cannot reach 3rd interval above the female. What should the male part do to support the melody? Go 3rd interval up and then down an octave?
Thank you