Sorry I misunderstood the question.
Deemusic you are not talking about volume or amplitude of parts.
You are talking about placement of pitches.
This is an area that I have some difficulty with. I have asked many people in this community for their methods ot teaching vocal harmony parts, and have never really gotten a straight answer.
The best way I know how to find choir parts is by first knowing how to sing the melody. I can find an interval below the melody for part two, or I can find an interval above the melody for part two. I sing in parallel with the melody. Like if the melody pitch goes up the harmony goes up, and vice-versa. Once two parts are established, part three can go above or below part two. But it should be parallel.
Gospel music is not polyphonic counterpoint with voices moving in contrary motion. Sometimes you can use oblique motion for effect. This is where a voice or voices stay at a given pitch and another voice or voices move up or down.
Regardless I never have two different tonalities going at the same time.
I must say, though I have heard some contemporary tunes recently that sound like the band is in one key and the voices are in another. This troubles me because many people who sing in choirs have trouble matching their voice pitch to the fixed pitches of an instrument as it is.
Some people who mean well and want to be a part of a church choir, simply are tone deaf. One church where I played briefly had an older man who had a hearing aid, and simply could not match his voice pitch to an instrument. In fact he couldn't sing a clear melody by himself. His rhythm was good, but the up and down of his pitches was very inaccurate.
Summary: Background voices should be in the same key as the lead vocal. In my opinion the background voice parts should be in a similar register as the lead vocal. You want tight harmony in gospel music. You don't want large distance from the lead vocal in the accompanyment of background voices.
brother scott
