Understanding Intervals - Part 2



OK, so we’ve established a name for each interval. Sorted? Not quite, there’s more.

There is actually more than one name for many of these intervals. Let’s have a look at a more detailed chart:

Fret	Interval name(s)
0 (open string)	Root, Dimished 2nd
1	Minor 2nd
2	Major 2nd, Diminished 3rd
3	Minor 3rd, Augmented 2nd
4	Major 3rd, Diminished 4th
5	Perfect 4th, Augmented 3rd
6	Aumented 4th, Dimished 5th
7	Perfect 5th, Diminished 6th
8	Minor 6th, Augmented 5th
9	Major 6th, Diminished 7th
10	Minor 7th, Augmented 6th
11	Major 7th
12	Octave, Augmented 7th

Now we see that the 2nd, 3rd, 6th and 7th can each be diminished, minor, major or augmented. Each of these variations are 1 semi-tone (one fret) apart. I’m not quite sure what the point of an augmented 7th is... its really just an octave... but anyway... ;-)
Also, the 4th and the 5th can be dimished, perfect or augmented.

Why do these over lap though? Why do we need an augmented 2nd when we’ve got a perfectly satisfactory minor 3rd with the same pitch?

Well, going back to the people who created our modern system of musical notation, they didn’t like having the same interval number twice in the same scale. I.e. if you wanted a scale with both a minor 3rd and a major 3rd you either had to call the minor 3rd an augmented second or the major 3rd and dimished 4th.

But, why do we care about such notes as an augmented 2nd? It just so happens that a chord very dear to the hearts of rock and blues players has an augmented 2nd. None other than the so called 'Jimi Hendrix' chord:

E-|---0---
B-|---8---
G-|---7---
D-|---6---
A-|---7---
E-|---0---

This chord has a root note (the low E string), two octaves (on the A string and high E strings respectively), a major 3rd (on the D string), a minor 7th (on the G string) and, the note that really kicks this chord into gear, a minor 3rd (on the B string)... Ooops, hang on, we already have a major 3rd in there, so that note is actually an augmented 2nd!

Understanding Musical Intervals - part 3 >>