3 note chords

Click here for the general overview

In the previous Pomodoro, we got to know the modes of the diatonic scale. In this Pomodoro, we will see that they are very handy in explaining chords.

A chord (or harmony) is nothing else than 2 or more notes sounding together. That can be pleasing to the ear, in which case it’s a consonant harmony, or not so pleasing in a dissonant harmony. You could think that “pleasing” or “not pleasing” would be totally a matter of personal taste, but there are studies that indicate the physiological nature of harmony (see this video).

In western folk music and bluegrass, we mostly talk about 3-note chords, with one 1 big exception which is the dominant 7th chord, that has 4 notes. But more of that later.

First, let us establish what a 3-note chord is. A 3-note chord is constructed by the root, the 3rd and the 5th of the mode. That’s it. No more, no less.

Indeed, each mode in a key has it’s own chord. But in stead of naming the mode, we indicate the chord with a symbol, or with a roman numeral. So, in the key of C for example these are the chords :

mode root	chord notes (1 – 3 – 5 of the mode)	chord name	indication	roman numeral
C	C – E – G	C (major)	C	I
D	D – F – A	D minor	D- or Dmin	II
E	E – G – B	E minor	E- or Emin	III
F	F – A – C	F (major)	F	IV
G	G – B – D	G (major)	G	V
A	A – C – E	A minor	A- or Amin	VI
B	B – D – F	B (half) diminished	Bdim or B-b5	VII

I suggest you play these chords, while someone else plays the notes in the key of C. You’ll hear how they match wonderfully together !

Probably there are some questions bubbling up. But before we address them, let’s take another example : the key of G (that has F#) :

mode root	chord notes (1 – 3 – 5 of the mode)	chord name	indication	roman numeral
G	G – B – D	G (major)	G	I
A	A – C – E	A minor	A- or Amin	II
B	B – D – F#	B minor	B- or Bmin	III
C	C – E – G	C (major)	C	IV
D	D – F# – A	D (major)	D	V
E	E – G – B	E minor	E- or Emin	VI
F#	F# – A – C	F# (half) diminished	F#dim or F#-b5	VII

Of course, you could continue building your own table for any key, but let’s stop for a while, because it seems we have a lot to talk about !

First, there’s a small point to notice : in the column of the chord names, you’ll see parts between parenthesis. That means that if you call that chord name, you can leave that part out. In fact, it is preferred NOT to mention it. So, you say “play G” for instance, and not “play G major”, or “F# diminished” and not “F# half diminished”. These parts between parenthesis are only there for clarification of the chord. (We’ll see later what diminished is).

Now, let’s have another look at the tables. We notice that, just as the modes were major or minor, so are the chords : there are major and minor chords. That’s quite logical, since the chords are built upon the modes, and they include the all important 3rd.

This means that the chords are major or minor by position. What I mean is that in any key :

• chord I which is built on the Ionian mode is always major
• chord II which is built on the Dorian mode is always minor
• chord III which is built on the Phrygian mode is always minor
• etc.

That’s why some music sheets don’t show chords, but roman numbers. That means you can play in any key and you just apply the appropriate chord number, according to the system above. The only thing you have to know is in what key the song is played at that moment.

Secondly, the vast majority of songs will not include all 7 chords belonging to the key. In fact, most bluegrass songs only contain 3 chords : I – IV – V. They happen to be the only 3 major chords ! Some bluegrass and old time songs have only 2 chords : I – V !

On the other hand, there are also a lot of songs that include chords NOT belonging to the system above. E.g. “Salty Dog” in G contains a E (major) in stead of E minor ! There can be a lot of reasons for these “out of key” chords, but that would bring us too far to explain (besides the fact that I don’t always know why !)

But in general, the system above can serve as a useful tool when you are searching for the chords of a song you don’t know. Most of the time, you’ll find the answer there !

Some other points to mention :

• a full guitar chord has 6 notes (one for each string), and a 3-note chord only 3, how’s that possible ?
  Well, yes, when you play a full G-chord on your guitar, you’ll hear 6 pitches, but only 3 notes. If you analyze the chord, you’ll play :
  • 6th string : G
  • 5th string : B
  • 4th string : D
  • 3rd string : G
  • 2nd string : B
  • 1st string : G

You see : only the 3 notes of a regular G-chord. Go ahead, and try to find what notes do you play on the regular C, D and A chords. It will always be the 3 notes of the chord. So yes, it is allowed to play the same note (or its octaves) more than once in a chord.

• Inversions : just as you can play a note more than once in the chord, you can also inverse the order in which they appear. The normal order is 1 – 3 – 5 (as in the G-chord above), but you can also play the first inversion : 3 – 5 – 1 (B – D – G) or the second inversion 5 – 1 – 3 (D – G – B). They’re all the same chord.
  
• As you have noticed, a minor chord is indicated by the name of the chord, followed by a minus-sign “-“ or the abbreviation “min”. A (half) diminished is indicated by the abbreviation “dim”. And that brings us to the question : what is a diminished mode or chord ?
  The answer is simple : not only this mode or chord is minor, but also it has a dropped (or diminished) 5th note.
  Let me explain. Chords I to VI all have what is called a “perfect fifth” : from the root to the 5th is always 3+1/2 steps, even for minor chords.
  
  But for only chord VII that is not the case : it has only 3 steps from the root to the 5th, which is called a diminished 5th.
  
  E.g. the diminished chord Bdim (B – D – F) : 1/2 step from B to C, 1 step from C to D, 1 step from D to E, 1/2 step from E to F = 3 steps.

The diminished chord is a great “passing” chord to go back to the root of the song. So if you play a bluegrass song, and you have a passage where you go from chord V to I, try fitting in the diminished chord VII just before you play the I. It won’t always work, but when it does, it will sound richer.

Mind you, a diminished chord on the guitar is not easy to take on all 6 strings ! I only use the upper or the lower 4 strings.

By playing the diminished VII chord, you substituted the “dominant” chord V chords. The dominant V chord is played a lot of times with a 7th note. That makes it a 4-note chord ! Let’s talk about that in the next Pomodoro !