Some notes about music.

Here are some interesting observations related to intervals (2 simultaneous notes), triads (chords with 3 notes), extended chords (4 or more notes), and chord progressions:

**For the purposes of this blog, I'll be basing all intervals, triads, extended chords, and chord progressions on the base note and scale of "C".

As you'll remember, some intervals are commonly perceived as dissonant, and some as being consonant; additionally, some intervals are given qualities such as "dark," "sinister," or "brooding," some are given qualities such as "happy," "positive," "anticipatory," and some (the perfect intervals) aren't really given a strong quality at all. Combine these intervals, though, and the qualities change quite drastically.

Because in a previous post we learned that the Major 3rd is one of the "happiest" sounding intervals, it would make logical sense that combining two of these intervals would give a very happy-sounding chord. So, to create this chord, you would simultaneously play the notes C-E-G#. This quality of triad is called an "augmented" triad; play it, and you will notice that it is incredibly dissonant, and not at all "happy" sounding.

In fact, the "happiest" triad in music is considered to be the combination of a major third, and a minor third. C-E-G. This quality of triad is called "major"--named so because of the major third contained between the tonic ("tonic" means the "base" note--in this case: C) and the next note of the triad.

It may follow next, logically, that the "saddest"-sounding triad would be the combination of two Minor 3rd intervals since the Minor 3rd is considered to be the saddest interval. If, however, you play two minor thirds, you get the notes C-Eb-Gb. This triad quality is called a "diminished" triad, and if you play it, you will notice that it is extremely dissonant.

In fact, the "saddest" triad in music is considered to be the combination of a minor third and a major third. C-Eb-G. This quality of triad is called "major"--named so because of the minor third between the tonic and the next note of the triad.

Here is where triads get (more)interesting:

If you take the 2nd or 3rd note of a triad and place it on the bottom, you create what is called an "inverted" triad. For example: take C-E-G, and invert it to be E-G-C. Notice now the the intervals, rather than being Major 3rd/Minor 3rd, are Minor 3rd/Perfect 4th. Now you might expect that this triad would sound minor... the minor 3rd is a sad interval, and the perfect 4th has no quality. BUT, instead, this inverted triad retains the exact same quality as the original triad. The other inversion, G-C-E, Perfect 4th/Major 3rd, also retains the quality of the original chord. This "phenomenon" works with all triads--diminshed, augmented, major, and minor--and also with all other types of triads and chords, with some very minor exceptions (not exceptions of which chords can be inverted... just some exceptions of which notes within those chords can be inverted into which positions.)


Next: extended chords. An extended chord occurs when you add another, higher note to any of the 4 qualities of basic triads. In this blog, I'll specifically be focusing on the "Dominant 7th" quality of chord. The notes for this chord are C-E-G-Bb. Adding this 4th note causes the "happy" C-E-G Major triad to become a positive-sounding and consonant "anticipatory" chord which wants to lead into another chord and sounds "unresolved" (because it wants to lead into the chord which is its resolution).

When you dissect this chord, you will notice this: the "stacking" of intervals goes Major 3rd/Minor 3rd/Minor 3rd, and from E to Bb is a Tritone (diminished 5th), which is considered one of the most dissonant and "sinister" intervals in music. Despite two minor intervals and the tritone, this extended chord is one of the least "sad" chords in music, and the quality has virtually no unsettling dissonance.


Lastly: chord progressions. A chord progression is a progression of chords. A chord progression can be as short as 2 different chords (although this is rarely called a chord progression), and has virtually no end as to the maximum number of chords it can contain (although typically a chord progression will cycle through about 7 or 8 chords at max until it returns to the starting chord). Within one key (the scale that the song is based in), there are 7 different triads and countless extended chords. These triads are based on each tone of the scale which the key is in, once again, I'll base them off of C. These 7 triads, besides being based on the 7 tones of this scale, also use only the notes from this scale to form the other intervals in the triad. For the entire scale, this would go as such:

C-E-G (Cmaj)
D-F-A (Dmin)
E-G-B (Emin)
F-A-C (Fmaj)
G-B-D (Gmaj)
A-C-E (Amin)
B-D-F (Bdim)
C-E-G (Cmaj)

So, a song, or a part of a song, which remains in one key, can use any of these triads and remain in that key. What this means is that a song can be in the key of C Major, and still use D minor, E minor, A minor, and B diminished chords. In fact, a progression could be composed mostly of these minor chords and yet still overall sound major if it starts and ends on a major (typically the C major) chord. The same goes for songs in a minor key: so long as they start and end on a minor chord, you can throw in virtually as many major chords as you want without it sounding major as an overall progression.

... Notice the pattern?

Triads and chords can contain many different qualities of intervals and yet those individual intervals have little bearing on the overall quality of the chord.

Chord progressions can contain many different qualities of chords, and yet those individual chords have little bearing on the overall quality of the progression.