Re: For guitarists of all levels...
All right, now we'll start with part 3: chords. I was initially looking at making this an audio lesson but will skip that to prevent ear torture, plus there's nothing theoretical about audio. Again we'll be borrowing heavily from concepts we learnt in part 1 and 2, notes and intervals. We will not allude to the circle of fifths again, but remember that we will be using it to build our scales and chords.
What are chords?
Chords are nothing more than three or greater number of notes played together. There are diatonic chords called 'power' chords, and we'll see a little bit about them as well. So simple - play three notes together, and you have a chord.
The first chord we'll learn today is Em7add11. It sounds complicated, but it's really not. It is the chord you play when you strum all the open strings on your guitar without fretting anything. We'll come back to explain this chord once we learn how to build chords.
As we already know, a scale consists of intervals. A chord is simply two or more intervals played together. The simplest chords are tritone (and the most widely used) which are three notes, or two intervals. We'll dive into those first, as they are the building blocks of harmony. I'll be working in the key of C, which has no accidentals. Hopefully that will keep it simple for everybody. For intermediate guitarists - you can use the circle of fifths to transpose, and advanced guys already know all this stuff anyway.
The basic tritone chord types are:
Major: Root, Major third, Perfect fifth
Minor: Root, Minor third, Perfect fifth
Augmented: Root, Major third, Augmented fourth
Diminished: Root, Minor third, diminished fifth
Building chords
I will first lay out the notes of C major:
C D E F G A B
We will need to build chords in each and every note in the key. The 'key' thing to remember is that tritones in this key will have ONLY notes from the key. As we kind of hinted earlier, a chord is a root third and fifth. Refer to the intervals lesson if you need to jog your memory on the names I'm reeling out here. Root is the starting note of the chord.
I will lay out all the chords for these notes, along with the intervals:
C (first degree): root, third, perfect fifth: C, E, G - C major
D (second degree): root, minor third, perfect fifth: D, F, A - D minor
Aha! why is the minor third F and not Eb? Because though we use notes from the key of C, when we build a chord we always do it referring the root note's scale, not the scale it is being created in. So we have to use the third in the key of D, not in the key of C. This way the chord is universal no matter what key you play it in. This can be confusing when confronted for the first time.
The third for the key of D is F#, and the minor third is F. Moving on:
E (third degree): root, minor third, perfect fifth: E, G, B - E minor
F (fourth degree): root, major third, perfect fifth: F, A, C - F major
G (fifth degree): root, major third, perfect fifth: G, B, D - G major
A (sixth degree): root, minor third, perfect fifth: A, C, E - A minor
B (seventh degree): root, minor third, diminished fifth: B, D, F - B diminished
Each key will have only one augmented/dimininshed chord, and can be used to great effect for contrast. 'All my loving' by The Beatles uses an C augmented when returning to root chord C, and it's great fun to play/listen to it.
Extending chords
We can also extend chords by adding notes to it. The most basic of these is the dominant, which is very common. We get a dominant by adding a minor seventh to the chord in the fifth degree. In the key of C, the dominant would be a G7. We construct a G7 by adding an F to it, so a G7 is basically four notes; GBDF. Every time we add a note after this, we number the chord after 7. For example we can construct a chord GBDFA, this would be a G9 (pronounced G dominant 9th). If we add the note without adding a minor seventh, it becomes an 'Add' chord. So a Gadd9 is basically GBDA.
Then there are suspended chords, referred to as sus chords. Here we drop the third and replace it with another note. The two most common notes are the 2nd and the 4th, giving us Dsus2, Dsus4 and other wonderful droning chords. Very easy to play on the guitar, and a boatload of fun, if a bit overused.
Lastly there are slash chords. Slash chords are basically telling you to play a chord with a different bass note. They are basically inversions, though there may be cases (like a walking bassline) where notes from outside the basic chord form are used. So a C/E is a C with the bass note from E (played after fretting the C and letting all strings ring), and a G/B is a G chord played with a B bass (so not playing the 6th string at all).
Now let's see how we arrived at that open chord. The notes are E, B, G, D, A. Basically we have the Em chord Which is E, B and G, and to it we add a minor 7th (D) and a fourth/eleventh (A). So Em + 7 (minor 7 = dominant) + 11th.
Power chords
Lastly there are power chords. Power chords basically drop the thirds totally, so all you are playing are root and fifth. A lot of guitarists double the notes, for more layering and texture. Power chords have an aggressive sound and can be used as harmony under major and minor melodies, and are thus heavily leaned upon in Rock music, which sometimes switches between major, pentatonic and related minor scales. Most heavy rock harmony uses power chords at one point or the other. 'Rock you like a hurricane' by the Scorpions is almost entirely composed on power chords, as is 'With or Without you' by U2.
Wrapping up
For transposing the chords we use the circle of fifths. There is no magic bullet to this stuff, you should be playing the chords a lot to get used to how they sound. There are hundreds of places to get chord shapes from. I hope you've downloaded the Nut chords program I talked about earlier, it gives you the chord shapes for every single chord, and it will play the chord for you so you know how it sounds. It also names chords for you, so if you hit a cool riff it will name that chord for you so you can impress all your friends with the new G9-5 or whatever you learnt. There's also a filter so you can avoid the funny shapes.
G9-5, for advanced guitarists, is played xx5453. Next part we learn how to decode chord shapes from the funny numbers I just gave, and we move to the instrument and learn basic shapes and CAGED. That will wrap up the lesson on chords, and exhausts all I know about guitar. I really don't know how to play it
