Do you have a swagger in your step? I mean, you’ve mastered nearly every interval in music. So why wouldn’t you be feeling good?
But there’s one more pair of intervals to look at before you can say you’re a true music theory ninja. And these intervals are easy because they’re directly on either side of the tonic (1). Immediately to the right of the tonic (in a clockwise direction) is the minor-second (b2). And to the left (in a counter-clockwise direction) is the major-seventh (7).
In the key of C, for example, these are notes Db and B:
Both of these notes sound very dissonant with the tonic. After all, they’re the respective dominant and subdominant notes of the tonic’s tritone. (They are positioned next to the tonic because of the rearrangement from the circle of fifths to the chromatic scale.) But they do show up in the tonic’s key to differing degrees.
The major-seventh (7) note, for example, is used a fair amount in any given key. And that’s because it is part of the key’s major scale. So it’s often used in melodies written in that key. For instance, B often appears in the key of C because it’s part of the C major scale. And because it’s also the major-third of C’s dominant note (G), the major-seventh holds a favored position in many songs.
The minor-second (b2), on the other hand, gets relatively far less play. So you’re less likely to hear it in the tonic’s key. For example, Db rarely shows up in the key of C because it’s dissonant with the tonic … and because it doesn’t sound very good with other notes in the key of C. So it usually gets benched come game time.
As usual, these intervals are also symmetrical in every key. And, as you can see, each tonic connects with its minor-second (b2) in a clockwise direction and with its major-seventh note (7) in a counter-clockwise direction.
And because these intervals are really just a series of half steps, you could say the entire chromatic scale is simply a sequence of both minor-second and major-seventh intervals. Yeah!