Quite a few people are having difficulty understanding why I have the Chord Analysis of the Coldplay piece in the key of, "F Minor." A number of readers believe the Coldplay piece is in; "Ab Major."
Many of you seem to be looking at this set of chords as if they are standing alone... The Chord Changes are not standing alone they have a MELODY behind them. If they were without melody the Coldplay progression could be played over/analyzed in; Ab Major, or even Db Lydian Mode, or in F Aeolian...
The resolutions of the vocal melody are what I am basing my chord analysis upon. Keep in mind that chord changes are only the backdrop for melodic contour. And, the last note, (and to a lesser extent the first note), of a melodic phrase is heard as more important than others - it generates melodic resolution and determines the structure of the chords appearing behind the melody line.
Take a look at the following melody...
The melody has one sharp in it's key signature. It begins on "B," and it ends on "G." The key signature of one sharp is the key of, "G Major." Is the melody in "E Minor?" Of course not, the melody is in, "G Major." Keep in mind that there are no chords given in the above example, only a melody. How do we then know that it is for certain in, "G major?" Because of the Melodic Contour. It's curve, (pitch climax), is to a "G."
The starting note of the above melody is, "B," and this is the third degree of the scale, (and the 3rd of the G major chord). The ending note of this melody is "G," the root of the key center chord and therefore the tonic of the melodic contour. If the line ended on an, "E," we would be analyzing the contour as, "E Natural Minor (Aeolian).
Note:
The terms "root, " and, "tonic," are often used interchangeably, however they are not the same. The term, "root," applies to chords, and "tonic," applies to scales and key centers.
Now, let's look at another melody:


The Key Signature states 4 flats, (the key of Ab Major). However, what is the motion of the melodic contour? Remember, we are looking for the destination pitch to determine the resolving note generating the strongest sense of melody resolution. The curve ends at an, "F." Thus, determining a sense of arrival to the destination of the tonal center. The resolution is showing this is a Minor Tonality key center.
The above melody is the transcribed vocal melody line from:
"Viva la Vida."
The key is; "F MINOR, (Aeolian)."

