What is the difference between a leading tone and a subtonic? What do you know about the term, ‘subtonic’? How do you understand it? Have you ever heard anything about it? If I should say, “the concept of leading tone and subtonic,” would you have what to say?
This article sets out to disclose the difference between a leading tone and a subtonic. The mystery of leading tone and that of subtonic will be unfolded. It’s all about the seventh tone of major/minor diatonic scales.
If the seventh degree of a scale is a major second (a tone, a whole step) below the upper tonic (as in the case of natural minor diatonic), it is known as a subtonic. You cannot call it a leading tone. I’ll let you know the reason as we proceed.
If the seventh degree of a scale is a minor second (a semitone, a half step) below the upper tonic (as in the case of major diatonic, harmonic minor), it is known as a leading tone. You cannot call it a subtonic. I’ll let you know the reason as we go further.
Why is it so? According to oxford advanced learner’s dictionary, the term “leading tone” means, “scale degree seven when the first scale degree is one half step higher than the seventh scale degree.” This is not too far from the already established fact. I’ll amplify it in case there is ambiguity.
Leading tone must be must be a minor 2nd (m2) below the tonic or upper tonic. Upper tonic (octave) is the inversion of tonic; the difference is the octave and of course, the frequency. For instance, P1 will become P8, and P8 will become P1 when inverted. I prefer using upper tonic for this discussion to avoid ambiguity.
The distance between leading tone and upper tonic is always a semitone (half step). If it is more than a semitone, it’s not called a leading tone, rather called a subtonic (just as in the case of subdominant and dominant).
Subtonic means “the note immediately below the upper note of a musical scale.” In other words, the note immediately below the upper tonic or octave is known as subtonic. That is only if it is not a semitone or a half step below. If it is a semitone below, it is known as a leading note.
In conclusion, leading tone and subtonic are terms associated the 7th degree of a diatonic scale. Leading tone is used when it’s a minor 2nd, a semitone or a half step below the upper tonic. Subtonic is rather used when it’s a major 2nd, a tone or a whole step below the upper tonic.