Music Theory FAQ

Here are some questions about Music Theory that have come into the Theta Music Mailbox from our members. Do you have any questions about music theory? You can submit them here.

Scales

What's the difference between scale degrees and chord degrees?

Intervals

What's the difference between the 1-5 and 5-1 intervals - Are they both perfect fifths?

Chords

Why does a C#7 chord contain an E# instead of F?
How do I construct a major triad with a given root tone?
What does it mean when a chord name has a '/' in it, such as A7/E?
What's the difference between a VII chord and bVII chord?
What is the meaning of Im/b3, Im/5 and IVm/b3?

Scales

Scale degrees indicate the position of a tone in a particular scale. For example, in C Major, the tone C is scale degree 1, the tone D is 2, E is 3, and so on. Chord degrees indicate the role of a tone in the chord. For a C Major chord, the tone C is the root of the chord, E is the third of the chord, and G is the fifth of the chord. Note that scale degrees are usually given as arabic numbers (1, 2, 3..), while chord degrees are written as root, third, fifth, etc.


Intervals

Assuming the interval is melodic (tones are played sequentially, one after the other), then:

  • 1-5 would be an ascending P5 if the second pitch is higher than the first. Otherwise it would be a descending P4.
  • 5-1 would be an ascending P4 if the second pitch is higher than the first. Otherwise it would be a descending P5.



Chords

Any seventh chord that has a root with letter name C must contain tones with letter names C, E, G, and B. In this case, we start with the C# Major scale (C#, D#, E#, F#, G#, A#, B#) and take the 1, 3, 5 and b7 scale degrees to get C#, E#, G#, and B (flat 7th).


You can construct a major triad for any root by first looking at the major scale which has the root tone as its tonic. Now, add scale degrees 3 and 5 to the root, and you have the tones of the major triad for that root. For example, to make a major triad with D as the root, begin with the D Major scale (D, E, F#, G, A, B, C#). Now simply take the tones in positions 1, 3, and 5 (D, F#, A). These are the tones that make up a D Major triad.


When you see a chord that has a '/', it means that the tone which comes after the '/' is the bass tone of the chord. So A7/E is simply an A7 chord with the E in the bass. Sometimes these chords are notated with the word 'on' instead of the '/': A7onE, C on G, etc.


The VII chord is a major chord built on the 7th degree of the major scale, while the bVII is a major chord built on the flatted 7th degree. For example, in the key of E Major, the 7th degree of the E major scale is the tone D#, so the VII chord for this key is D# Major (D#, F##, A#), while the bVII chord is D Major (D, F#, A).


Im and IVm refer to I minor and IV minor chords. For example, in the key of C Minor, Im is the Cm chord and IVm is the Fm chord.

/b3 means that the b3 of the chord is the lowest tone. In the example above, a Cm chord consists of the root (C) the b3 (Eb) and the 5 (G), so Im/b3 means a Cm chord where the lowest tone is Eb. Likewise, a Im/5 would be Cm chord where the lowest tone is G.

In the key of Cm, the IVm chord (Fm) consists of the root (F), b3 (Ab) and the 5 (C), so a IVm/b3 in Cm refers to an Fm chord where the lowest tone is Ab.