I just posted this on the Ubuntu forums as someone asked, so I thought I'd stick it here in case anyone cares...
A scale has 8 notes in it. These go:
1st/root/tonic
2nd/supertonic
3rd/mediant
4th/subdominant
5th/dominant
6th/submediant
7th/subtonic
8th/octave
The note names are to do with how they sound when moving between chords. Play an A (tonic) and then play a D (dominant in the key of A) and note how it sounds coming after the A. Then go to back to the A and see how that sounds. The tonic chord is your "home" chord. Whatever chord you're playing will always want to resolve to that home chord. You can create "tension" in songs by not resolving to the tonic.
What these notes are will depend on whether you're using the major or minor scale. Using E as an example (as it allows you to use the open E and it closely follows your fretboard dots), the patterns go as so:
1 2 3 4 5 6 7 8
major E (T) F# (T) G# (S) A (T) B (T) C# (T) D# (S) E
minor E (T) F# (S) G (T) A (T) B (S) C (T) D (T) E
(T stands for "tone" which is two spaces on the fretboard, S for "semitone", which is just one)
You'll notice that some of the notes differ between the scales, while others stay the same. The 3rd, 6th and 7th are intervals which determine the "sex" of a chord (i.e. whether it's major or minor).
In a chromatic scale (chromatic means all the notes, going up in semitones) the intervals go like this (again in E):
E - root
F - minor 2nd
F#/Gb - major 2nd
G - minor 3rd
G#/Ab - major 3rd
A - "perfect" 4th
A#/Bb - Augmented 4th/Dimished 5th/tritone
B - "perfect" 5th
C - minor 6th
C#/Db - major 6th
D - minor 7th
D#/Eb - major 7th
E - octave
Notice that there's also a major and minor 2nd, but both the major and minor scales use the major 2nd. The minor 2nd is only used in more complex scales such as modes. (we don't need to go into those at this level)
Also, the 4th and 5th are called "perfect" because they are neither major nor minor.
The A#/Bb has multiple names. Augmented basically means "add 1", while diminished means "subtract 1". The "tritone" name comes from the fact that it has an "evil" sound. Check out the main riff to Black Sabbath, that's just root, octave, tritone.
On sharps and flats: A lot of people ask "what's the difference between A# and Bb?" The answer is nothing. They are "enharmonic" which means they are the exact same note. The reason for the two names is that a scale should contain every note from A to G. This means E major is E, F#, G#, A, B, C#, D#, E rather than E, Gb, G#, A, B, Db, D#, E (exact same notes, except now you have no F or C note but two G and D notes). This is also why you might end up seeing E# or Fb (really just F and E respectively) and B# or Cb (really just C and B) when they don't technically exist...
The best way I learnt about intervals was playing powerchords. A basic powerchord is made up of the root and the 5th (sometimes with an octave as well). If you substitute that 5th for a different interval (say a minor 6th), you get a much different sound. Certain combinations of notes will sound "nicer" than others. Using fifths or fourths will give you a clear, heavy sound, while root and minor sixth will give you a dark, sad sound. You can take this to an extreme with something like root and minor second, which will sound horrible, but maybe you want that...
Building chords:
Basic chords are built off thirds. This means you count three steps up in a scale. So in C major (because it has no sharps or flats, so it's simple):
C 1
D 2
E 3 1
F 2
G 3 1
A 2
B 3 1
C 2
D 3 1
E 2
F 3 1
G 2
A 3 1
B 2
C 3
Any chords will include the notes numbered 1 or 3. That diagram spans two octaves. The first count gives you the root and third. The second gives the root, third and fifth, which is your basic triad (play a C major chord and work out what notes you're playing, it'll only be C, E and G).
The third count gives you a seventh chord, then a ninth (a major 2nd, but up an octave), then an 11th (a 4th up an octave), a 13th (6th + octave) and then back to your root note. You usually won't go past a 7th chord, unless you start playing Jazz (or some Hendrix as he uses an augmented 9th chord a lot).
If you do this counting in thirds starting on other notes in the scale, you get the chords which are "diatonic" (belong to) to the key you're in. So, in C major:
C D
E F
G A B C - C
C
D E
F G
A B C - Dm
C D
E F
G A
B C - Em
C D E
F G
A B
C - F
C D E F
G A
B C
D - G
C D E F G
A B
C D
E - Am
C D E F G A
B C
D E
F - Bd
This gives you a pattern of I - ii - iii - IV - V - vi - viid, the chords for minor being i - iid - III - iv - V - VI - viid
The "d"s stand for "diminished", this means that if you look at the B chord, you'll find it has a flattened 5th, compared to the others which have a normal perfect 5th.
You get more complicated/interesting chords by using the other notes in a scale. Play the chord: X02200 (low to high), this is an Asus2 as the 3rd has been "suspended" and replaced by a major 2nd (also meaning it's neither major or minor as it has no 3rd to define it as such). You can also get suspended 4ths or chords like a G6 (320000, where the final high G is replaced with an E, which is the major 6th of G).
When you're playing a chord, look at what notes make up the chord and how they relate to the root note.
Inversions/slash chords:
At times, you might see a chord with a name like this: D/F#, what that basically means is that you're playing a D, but the lowest note you hear is an F#. This is called an "inversion" because the F# is part of a D chord (D, F#, A) but it's lower than the root of D. Take a look at the chord in question: 200232, the notes in it are F#, A, D, A, D, F#.
I think that's about it for what you could need to know about Keys at this level. Hopefully that's given you a better understanding of how notes and chords work together and how chords are constructed and how different chords fit into different keys. Of course, all these rules can be broken to create different effects and such. And obviously you don't need to know all this when playing a song or to think about it when writing a song. Mostly it will rely on your ears, so make sure you listen carefully to how things
sound.
