Beginners’ Theory: Chords
Whether you want to study theory to go on the look at our jazz improvisation pages, or whether you want a preliminary explanation of some of the concepts in our beginners impro course Taming The Saxophone vol 2, you should find a lot of useful material her.
As you probably know, there are 7 notes in a major scale. In C these are C, D, E, F, G, A and B. We number these 1 to 7, often with roman numerals instead of note names, which makes it easier to think about this in any key.
In the key of C:
In the key of F
As you can see, by thinking in numbers this system is useful when you are discussing harmony in general and do not need to be in a specific key.
In the very simplest harmony system, we add two other notes to each of these notes so there are three notes in all, sounding together (in harmony). This simple three-note chord is called a triad. To build a triad you take a note (which can be any note) and add alternate notes of the scale above it.
When you take a note of the scale and build a chord on it, that note is called the “root” of the chord. To make this a bit clearer we shall now take a few of these notes in the key of C and build some triad chords. It helps if you can play them on a keyboard so you can hear what the chords sound like when the 3 notes are played at the same time, or spread out (played as an arpeggio)
The I chord in the key of C
In any key, chord I called the tonic. Think of this as “home”. As this is built on the 1st note (aka the tonic), it can be useful to think of this as the home chord as it can sound like it is at rest rather than “needing” to progress to a different chord. Usually a tune in a given key will end up on the tonic chord.
To make the chord we go up the scale scale starting on a root note of C, and use the 3rd and 5th notes along with the 1st (ie the root = C in this case)
You can see from this that by missing out the alternate 2nd and 4th notes, we end up with the triad of 1st (root) 3rd and 5th.
Chords can be more complex, and contain four or more notes. The same principle applies: miss out the alternate notes:
Don’t Get Confused
Whatever chord we play, we can identify the notes in the chord using the numbers.
- The note we build the chord on (aka the root) is the 1st note.
- The next note up we call the 3rd of the chord – remember we count up the scale from 1 but miss out the 2
- The next note is the 5th – we continued counting up the scale but missed the 4)
- The next note up is the 7th – like wise we missed out the 6th
It may seem odd that the second note of the chord is a 3rd, and the third note of a chord is the fifth, but remember, a chord is made from alternate notes of the scale so we count the scale degrees but miss out the 2nd and 4th to build the chord.
The II chord in the key of C
The root note of this is D (the second note of the C scale). To make the chord we go up the scale of C, but this time starting on starting on D (In roman numerals note II of C). As before, we omit the 2nd and 4th notes to make the triad based on D
Once again by missing out the alternate 2nd and 4th notes, we end up with the triad of 1st (root) 3rd and 5th. It’s useful to differentiate between the roman numerals and arabic numerals. The roman numerals (I – VII) always refer to the note as relative to the key you are in, i.e. relative to the tonic. These are the root notes of the triads in that key. The arabic numerals (1st, 2nd, 3rd) refer to the notes relative to each of those chord root notes (I – VII). make sure you understand this, it may be easier to grasp in musical notation:
In other words:
- Each chord built on a degree of the major scale (shown as roman numerals I to VII) has it’s own chord.
- The root note of that chord is shown by the arabic numeral “1”
- The 3rd and 5th notes are counted upward from that root (NOT counted from the tonic of the key)
This chart demonstrates the chords built on each degree of a C major scale.
Part 2: Chord Sequences
Chords are used to accompany single melody lines. This is often done by an instrument capable of playing chords (e.g. a keyboard or guitar) or else by several instruments or voices added together to form chords (e.g. a band or choir). I mentioned above that the I chord (or tonic), can sound “at rest”. Other chords can often sound as if they want to change, either back to the tonic or to a different chord. This is because there is a certain amount of tension, either because they are simply not the tonic chord, or else because the notes within the chord create tension with each other. The use of tension (and it’s subsequent release) is a very important part of music, either in adding interest or creating emotions as the chords move from one to another. When you add harmony to an existing melody, you need to think of two important things
- The chords must fit the melody. This means that significant notes of the melody are notes of the current chord.
- The chords often move from one to another in a way that helps to create tension and release, or interest. You can think of a chord sequence or progression as a musical journey.
To get a good idea of this you must play and listen to the chords. I suggest you get hold of a keyboard and start learning where the notes are. You don’’t need to be a virtuoso pianist, but you must be able to play chords, even slowly, if you are going to learn music theory.
First of all play a C triad followed by a D triad using the charts above to work out the notes. You will hear that whereas the C sounds like “home”, the Chord on D sounds like you have gone somewhere else. This is the start of a journey.
Possibly most important chord change is from the V chord to the I chord, ie G to C in the key of C. This is called a perfect cadence and usually happens at the end of a tune, and also at the end of a phrase within the tune. I mentioned above that when you go from a C chord to a D minor chord it is like the start of a journey. If C (chord I) is home, D minor (chord II) is setting off somewhere else. The G chord (chord V) is the journey home so it is very useful that this chord has the most tension waiting to be released when you finally arrive home.
I mentioned before about tension within the notes of a chord. The V chord (called the dominant chord) is a very good example of this, but first we need to extend the chord. So far we have been looking at three note chords, or triads. The same principle of creating the chords is involved. We are now going to make a four note dominant chord. This is particularly useful because even with music that uses simple triads, more often than not the V chord is extended to a four note chord to take advantage of the extra tension that this chord is capable of when it is most often needed: the final cadence.
Creating a Four-Note Chord
Following on from our method of creating triads, to make a four note chord we just continue counting up the scale from the root of the chord. So if the root is G, we count up the C scale from G and use the alternate notes: root, 3rd and 5th as with a triad, but continue one more step: miss out the 6th note and add the 7th:
To differentiate between this and a G triad we call this a G7 chord. In this particular chord (along any V7 chord of whatever key), the interval between B and F (known as a “tritone” as it is made up of three whole tones) is one that has a lot of tension. This used to be called the devil’s interval as it was considered very dissonant. These days our ears are more used to such dissonance. Play this chord on the keyboard, then play just the tritone. You will easily hear how the B seems to want to resolve the tension by moving up to a C, and the F wants to resolve the tension by moving down to the E. Guess what? These are the most significant notes of a C major triad: the C because it is the root and tonic of the key, the E because that is what defines it as a major type of chord. So not only have we just created tension by adding a note (the 7th) to a chord, we created extra tension because that particular note sets up a certain amount of dissonance within the chord, and this tension finds release by progressing to the tonic chord and so completing that journey (or part of a bigger journey):
|Home||Set off somewhere||Journey back||Safely Home|
|Chord I (C)||Chord IIm (Dm)||Chord V7 (G7)||Chord I (C)|
This exercise demonstrates a simple journey from G7 to C. The first one uses just the chord tones, the second one introduces passing notes between the chord tones to create a scale.