Originally Posted by Muse-ic
That doesn't make sense to me. It's simple math. If you have a melody harmony is going to be an interval of the melody note. Take middle C as an example. You look at the C chord. You know that the third above, (E- major, Eb- minor), or the fifth above G, is your basic harmony. It can be more complex however the third can give an instant starting point.
Once you develop an ear for music harmonizing is as easy as breathing. You start hearing that interval and it goes hand in hand with the melody. You can also develop more creative harmonies with chord variations and dissonant intervals.
If you are talking about creating a melody once you have your chord progression keep in mind chords can be the initial melody as your ear and people who listen will naturally hear that as the melody.
What you are talking about is imagining the melody and harmony simultaneously, which I would argue is the correct way.
By harmonising a melody I mean you take a melody and design a chord structure around it that wasn't intended when the melody was created. Not saying it is wrong or can't be done, just saying it is pretty hard to do . A melody doesn't always stay in the basic 1 3 5 harmony. And just going down all the 12tones or even more to see which one might fit seems like a time consuming effort. I mean the C could be the root of a C major chord but it also could be the 9b on a B chord. It might not even be a C, it might be a #B as the major 7 of a #C chord.
By melodising a harmony I mean you take for instance a progression C F G and you just use the basic chord tones to build your melody like G C B or C A B. Again not wrong but rather a bit too easy.
It is just a perspective.