johans said:
Okay, I'll take it back a bit...
I'm guessing you're familiar with the basic major scale. Let's use C major, simply because it has no sharps or flats, if you were to play it on a piano, you'd only need the white keys. It goes:
C, D, E, F, G, A, B, C
To play this you'd start with any C on your bass, let's go from the C on the first fret of the B string, since you have a five string. Go up two frets and you find the D. Go up another two frets and you find the E. Go up just one further fret and you find the F, and so on...
C
+2 frets
D
+2 frets
E
+1 frets
F
+2 frets
G
+2 frets
A
+2 frets
B
+1 frets
C
All basic major scales use that formula (+2 +2 +1 +2 +2 +2 +1)
We ought to drop the "frets" as this theory applies to all instruments regardless of whether they're fretted or not. The correct name for this difference in pitch is a "semitone".
Triads are the most basic chord. They're constructed from three notes: a starting note which we call the root and which names the chord; a note two degrees above that called the third; and a note a further two degrees up called the fifth.
If we were to start with a C root note, we'd go up two degrees to E (which in this case is the third) and up a further two degrees to get the G (the fifth).
Relating that back to the major scale, we find that the E is four semitones up from the C and the G is seven semitones up:
C
+4 semitones
E
C
+7 semitones
G
This particular triad is called a C major triad, because it is rooted at C and can be constructed from the 1, 3 and 5 of the major scale. All major triads use this formula of a root, a third that is four semitones up from the root, and a fifth that is seven semitones up from the root.
If you were to start with a D root, using the C major scale, you'd have D (root), F (third) and A (fifth)
D
+3 semitones
F
D
+7 semitones
A
Notice that the distance between the D and F is only three semitones, whereas it's four semitones in the C major triad? This is what distinguishes a "minor" triad from a major triad.
We call a third that is four semitones up from root a "major third" and one that is three semitones up a "minor third"
How's that?