Theory 101. Part 2

author: TigerSteve date: 07/15/2010 category: the basics
rating: 8.6 / votes: 7 
Ok, for the main part of this lesson I'm going to be basing this information on triads (a chord built from 3 notes). Iv tried to makes this as painless as possible so please excuse the language use as it is to save confusion, especially for me! And please refer to part one for any confusing terminology. It should be explained there. In my last lesson I went over scales. Scales are great in the own right but there needs to be something behind the scale to bring out its 'flavour' or 'sound'. A chord is defined as a group of notes played together. The number of notes can vary but it is generally a minimum of 3. Within music there are thousands of different chords ranging from a standard C major to an Eb7#11b13 (yes, its a real chord) but its not as confusing as you might think. But to save confusion I will go through only 4 chord types. Major, minor, augmented and diminished. A major triad is build up of 3 notes. A root, a major 3rd and a major 5th (also know as a perfect 5th or P5). So if we use the C major scale to make a C major triad we get this.
 C  D  E  F  G  A  B  C
 R  2   3  4 5  6   7  8ve  (8ve means Octave)

 Major triad = R, M3, M5
So a C major triad contains the notes C (R) E (M3rd) G (P5) (side note, a capital M represents major and a lower case m represents minor) A minor triad differs from a major triad by one note. Instead of having a major 3rd it has a minor 3rd. To find the minor 3rd we take the major 3rd and move it down by a semitone. So a C minor triad would look like this.
 C  D  E  F  G  A  B  C
 R  2   3  4 5  6   7  8ve 

 Minor triad = R, m3, M5
We take the M3 and move it down a semitone so E becomes Eb So a C minor triad contains the notes C (R) Eb (minor 3rd) G (P5) Although there is not much of a difference between these triads they sound very different. A major triad can be described as a 'happy' sound in contrast to a 'sad' minor sound. The next two triads Im going to show are not too dissimilar to these but their tonality and sound are very different! The first one is the Augmented triad. It is built up from a Root, major third and a sharp (raised) 5th. So it can be seen as a major triad with a #5. This means, if we are looking at a C aug(mented) triad, that the G would become a G# as the 5th has been sharpened by a semitone. So...
C  D  E  F  G  A  B  C
 R  2  3  4 5  6   7  8ve 

 Augmented triad = R, M3, #5
We take the M5 and move it up a semitone so G becomes G# So a C aug triad contains the notes C (R) E (major 3rd) G# (#5) The last triad is the diminished. A diminished triad can be seen as a minor chord with a flattened 5th so we get..
C  D  E  F  G  A  B  C
 R  2  3  4 5  6   7  8ve 

 Diminished triad = R, m3, m5
We take the M5 and move it down a semitone so G becomes Gb So a C dim triad contains the notes C (R) Eb (minor 3rd) Gb (minor 5) It is these differing note intervals which give any chord its sound. Now this is the extreme basics of chord building but hopefully this lesson can be used with part 1 and will make sense and can be used in conjunction with scales. Please ask if you have any question. Thats all for today. Hopefully another one will be up at some point.
More TigerSteve lessons:
+ Theory 101. Part 1 The Basics 01/05/2010
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