Melody over chords

A song has two layers living together: the melody, the line you sing on top, and the chords, the harmonic support sounding underneath. They are not heard separately: each melody note is perceived in relation to the chord sounding at that instant.

That is why the same note can change role depending on the chord. An E over a C chord is a chord tone (the third) and sounds stable; the same E over another chord may sound like a tension asking to resolve. The note does not change: the chord underneath does, and with it the feeling.

The melody notes that fall on the strong beats (the accented pulses of the bar) usually coincide with chord tones of the current chord: they are the resting points where the melody settles. The notes left in between, on the weak beats, are usually decorations — passing or neighbour tones — that brush over and quickly return to a chord tone.

Think of the chords as stepping stones across a river and the melody as the one crossing them: it lands on the stones (the chord tones) on the strong steps and only brushes the water in between (the decorations) before reaching the next stone. As long as the important steps land on stones, the crossing feels safe.

Knowing which notes fit each chord is therefore the basis of composing, improvising and training your ear: it lets you justify every note as a chord tone or as a decoration that resolves, instead of picking them at random from the scale.