Basic Chord Theory

[stevehollx]

djmojo asked for some help with chords and how they were strctured, so here is some quick info:

 

Part I: Constructing Triads and 7th chords

 

The 2 most basic types of chords:

 

Chords containin a 1, 3, and 5 interval

these include Major, Minor, Augmented, and Diminished chords.

 

and

 

Chords containing a 1,3,5,7 interval

these include Major-Minor 7th, Major 7th, Minor 7th, dim7th, and half dim7th

 

Part A: Triads

 

Ok, so the first thin you need to do is pick the root of the chord. Let's say we will construct a C chord, since it has an easy key sig to work with. So the C major scale goes like this:

 

C D E F G A B C

 

Now basically intervals are the distance 2 notes are from eachother, so to form a major chord, we need the 1,3 and 5. This would be the C E G, since they are the first, third, and fifth notes in the C major scale. Now Thats the notes that make up a major chord. Arrangr those to any fingering you like on your fretboard. These three notes [CEG] are commonly referred to as a triad. A major triad is simply any 1,3,5 notes of a major scale. Now with the major chord, you can vamp it to be 3 other chords. Here is how:

 

Minor chord: Flatten the 3rd a half step. Leave others the same.

Diminished: Flatten the 3rd and fifth a half step.

Augmented: Sharpen the 5th a half step. Leave others the same.

 

So, we have these 4 chords:

 

C E G : Cmajor

C Eb G : Cminor

C Eb Gb : Cdim

C E G#: Caumented

 

Part B: 7th chords

 

7th chords contain 1,3,5 like a major chord, but also have the added 7th in there. The 7th is the leading tone when it is a half step away from the tonic [root note of scale]. This creates a strong need for resolution. Okay, so we will work in C again. First, here is a C major 7th:

 

C E G B

 

notice it is just like the Cmaj but with an added 7th, like it should be. Okay, now we can form other types of 7th chords off of these, as well.

 

minor: Has a minor triad and a minor [flatted] 7th

C Eb G Bb

 

Major-minor 7th: Has a major triad and a minor [flattened] 7th

C E G Bb

 

1/2 diminished: Has a diminished triad [3 and 5 flat] and a minor [flattened]7th

C Eb Gb Bb

 

Diminished 7th: Diminished triad and a diminished 7th [flattened a WHOLE step]

C Eb Gb Bbb

 

Now notice two things. With a dim7, we introduced a diminshed interval in the 7th. This is when an interval is flattened a whole step. Also note that it is written Bbb, not A. This is because if it were A, it would be a 6th [since A is the 6th note in the C major scale]. Then even though it is the same note, it would not be a Perfect 6th interval, not a dim 7th like we want. This is an important concept in theory. If it is still unclear, ask and I'll try to explain in more detail.

 

So basically that is how common chords are constructed.

[thamiam]

Great post! Let me just add one simplified note for people who might be a little overwhelmed.

Want to build a chord? Get a 7-note scale (major,minor, diminished, etc... not pentatonic) (use a scale generator, or one you know) and simply take every other note and stack them. When you get to the end go to the beginning again until you have taken every note.

The difference between chord and scale is basically one of order. Same notes, same everyhting, but chord stacks vertically every other note, and scale lays out horizontally every note.

So when you see the term 'scale', think 'chord/scale'
When you see the therm 'chord', think 'chord/scale'

It tends to clear up some confusion.

[stevehollx]

Part B: Inverting chords

Chords like to be placed in chord progressions, as you must already know. One oft he neat things about chords is you can write somethin using just one type of chord, and it can still sound like it has a lot of movement. This can happen by inversions. Here is what it is basically.

We will use C again, since its easy to work with.

A Cmajor triad is:

C E G

Now, a normal C chord will have the notes played in that order. However, a chord does not need to be in that order to remain that chord. Because it contains the C E and G notes, no matter what order it lies in, it will always be a Cmaj chord. You can arrange the notes any way you want basically. Inversions are noted by what note is on the bottom.

So a normal chord will have the root note of C on the bottom [bass note]

First inversion will have a E in the base, and the other two notes can be whereever and in any order, just as long as they are above the bass note. This is noted as a 6 chord. [i.e. C^6]...the ^ is just my way of noting that the number is a superscript. its like an exponent in math class.

Second inversion- G will be in the base, witht he other notes in any order as long as they are above it. This is noted as a 6/4 chord [C^6/4]

Ok here is an image in musical score to help clearify a little:



Ok as you see the frist section is a plain Cmaj. The second is two ways for a C^6, and the 3rd is 2 ways for a C^6/4. Note that these are not the only was to play inverted chords, but it is just an example to show that it only matters of what the base note is for the inversion. How this makes sense. You can also invert 7th chords, the same way. The notations for these are as follows:

normal: C^7
1st inv: C^6/5
2inv: C^4/3
3 inv: C^2

If oyu are wondering whgat the numbers mean, it is the interval the notes are away from the base note. Noted that don't change in interval are not noted [thats why 6 isn't written as 6/3].

Hope this helps. Happy picking.

Steve

[djmojo]

thank you triads and inversions, now I have some more musical words to throw around when I ask questions...

alright, part 3?

Are there any good easy to follow readings on the net somewhere that list some more things I could come back here and ask questions about... I want to understand things better like chords and modes and how the whole thing fits together.

thankyou for your huge posts very helpful to everyone.

[Reeko2]

Originally posted by stevehollx Major-minor 7th: Has a major triad and a minor [flattened] 7th C E G Bb

 

 

Most people recognize this as a 7th chord or Dominant 7th chord.

C7

 

Other than that, it was very informative.

[mukuzi]

Originally posted by stevehollx Diminished 7th: Diminished triad and a diminished 7th [flattened a WHOLE step] C Eb Gb Bbb With a dim7, we introduced a diminished interval in the 7th. This is when an interval is flattened a whole step. Also note that it is written Bbb, not A. This is because if it were A, it would be a 6th [since A is the 6th note in the C major scale]. Then even though it is the same note, it would not be a Perfect 6th interval, not a dim 7th like we want. This is an important concept in theory. If it is still unclear, ask and I'll try to explain in more detail.

 

 

I think you need to rethink this part of your theory.

 

A 'diminished interval' means down a semitone

So the Cmaj scale contains a C diminished chord?

It may have a B diminished chord, as there are really only two diminished chords anywhere on the fretboard.

 

The Bbb is in relation to enharmonic