Let's start with the excerpt...
The key signature is zero sharps/flats, and the beginning harmony is
E with the final close
Am so the key is
D♯ of the opening two bars is a decorative figuration of an
Am chord. The chord tones are highlighted in the image above in blue, while the non-chord tones are circled in red.
Non-chord tones can be found in diatonic and chromatic forms. The
D♯ could be called a chromatic auxiliary or chromatic neighbor tone, being an auxiliary or neighbor of the
Am chord tone
D natural imply some kind of dominant chord on the third beat which would lead to the
Am chord, but we can skip of that particular detail as it isn't directly about the
Chromatic non-chord tones are a common way to encounter tones from outside of the key signature. Some other ways to find chromatic tones are:
- the raised sixth and seventh scale degrees in minor keys
- secondary dominant harmony
- borrowed harmonies (usually chord borrow from the minor mode when the main key is major)
- certain chords that usually are in the "advanced" part of a harmony textbook like augmented sixth chords, neapolitan chords, or fully diminished seventh chords, those chord tend to precede the dominant chord
...an augmented fourth above the tonic of A...(I'm beginning to suspect that this part of the song is actually in E Phrygian, and that the D♯ is a leading tone
It's interesting that you describe the
D♯ as an augmented fourth (
A4) above the tonic
A. Of course that is true, but I think there is a subtle distinction between relating the
D♯ to the tonic
A or the chord tone
E. Speaking of an
A4 above a tonic suggests, to me, an alteration of the diatonic
P4 above the tonic, and alteration of the subdominant scale degree, which could possibly be functioning as a leading tone to
E provided the harmony actually reflected that function.
If that were the case we would expect the
D♯ to be part of a
D♯dim, a type of dominant chord, moving to a
Em chord. You could really make that particular harmonic function, and the
A4 relationship, and subdominant alteration, by harmonically sounding the
D♯ together, resolving it to
But, that does not actually happen. Harmonically it is just an
Am chord with decoration. In this case the notable relationship is simply the half-step below the chord tone.
There is nothing phrygian going on, but that is another matter altogether. It would require a discussion of modal harmony. Suffice to say our harmony is clearly tonic/dominant and the mode is clearly minor. It's in
It seems strange that you know terms like augmented fourth, phrygian, natural minor, diatonic, leading tone, etc. but don't understand where chromatic tones come from. Don't take my comment the wrong way. I'm a little suspicious of your theory sources. You might want to get a good college level harmony textbook. Kostka/Payne, Harmony is a well known text. Piston, Harmony is another. There are others you could use, it might depend on what is locally available for you. Do some research. Find a well cited book from an author who is a professor of music.