Hi Moonbeam.

Regarding the major/minor pairing, you are correct provided the composer has used the natural minor (also called the Aeolian mode if one uses the nomenclature of the church modes). The natural minor mode is often used in folk songs.

The following explanation is overly simplistic, but I have found it a useful perspective when writing songs. In classical music, the primary triads [3-note chords based on the first (I), fourth (IV) and fifth(V)] notes of a scale are usually the basis of harmony for that key. The secondary triads [the chords based on notes other than I, IV or V] are usually used to add shades of audio 'colour' through harmonic variation to the foundation created by the primary triads.

Classically, the minor key is less clear-cut than the major key. The reason for this is that in addition to the natural minor, there is also the harmonic minor and the melodic minor. As their names imply, these versions of minor keys are used for harmony (determining the primary and secondary chords) and writing melody.

This gives the three main minor keys. (There are other minor modes but these are less common.) I have used the various A minor scales below to explain the differences.

A natural minor: A B C D E F G
with primary triads Am (I), Dm (IV) and Em (V)

A harmonic minor: A B C D E F G# A
primary triads Am, Dm E; the major chord V has a stronger dominant effect than the minor V in the natural minor

A melodic minor: A B C D E F# G# A (ascending form) A B C D E F G A (descending form)
primary triads Am, D, E (based on the ascending scale)
primary triads Am, Dm, Em (based on the descending scale)

In a great deal of music, it is more than likely that the writer has used G# (raised seventh note), and possibly the raised sixth note (F#) in either harmony or melody if the song is in a minor key.

This variation of notes between major keys and their relative minors can create issues, especially in Realtracks based on melodic sequences such as Soloist or Background Realtracks.

  • For example, if leave the key set to C major and write a song in A minor, it is more than likely that I will use either E or E7 as the dominant chord V in a chord sequence that returns to the tonic chord (Am). The progression E (or E7) to Am is the most satisfying progression to close a section. This is called a perfect (or authentic) cadence. The net result is that with the key set to C major and the harmony based on A minor (i.e. BIAB's chordsheet's chords), I could have a musical clash if an E7 chord plays against a melodic sequence that contains the note G (rather than G#). This is because setting the key to C tells BIAB to search for melodic sequences based on the C major scale (with no G#) rather than melodic sequences based on the A minor scale (with G#).


I know the above might be confusing to read, but I wanted to provide some terminology that will allow readers of this post to search the internet if they want to investigate the musical differences between major and minor keys.

--Noel

MY SONGS...
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