Here is the third instalment in our series on intervals, and this time we’re going to examine the third.
Firstly, what is a third? If you read the last article in this series, about “the fifth“, you’ll probably already expect this to be a multi-part definition. You see, every interval is defined by at least two things. The first of these things is the distance in letters (i.e. how much further along the alphabet it is).
In this case, we get this as the first part of the definition:
A Third is a distance of 3 letters
Therefore, A to C is a third (A, B and C = three letters), C to E is a third (C, D and E), G to B is a third (G, A and B) and so on…
…that’s the easy part. The more complicated part happens when you look at these intervals in terms of the distance on the fretboard- the second thing that our definition needs.
According to the definition above, A to C is a third- and that goes for any type of A note, going up to any type of C note. For example, A to C would be a third, but so would all these variations:
A to C#
A# to C
A# to C#
A to Cb
Ab to C
Ab to Cb
The problem being that these are slightly different distances on the fretboard. I mean, obviously A to C is going to be smaller than A to C#, right?
Well this is where the third gets interesting! The A to C# is called a major third, and is 4 semitones (or 4 frets) wide- so for example: from the A on the 5th fret of the E string, to the C# on the 9th fret of the same string.
The other main type of third is our A to C, and it’s one semitone smaller than the major third (i.e. it’s 3 frets distance). We call this other type the minor third. An example of the minor third would be the A on the 5th fret of the E string, to the 8th fret on the same string.
Hint: Ever wondered what made some chords “major” and others “minor”? Well it’s which type of third they have!
The third is the note that’ll really bring out the emotion and tonality of a chord- try to target it if you want to sound really melodic.
The Major Third
Here is a major third (C to E) in tab:
You will find this interval in such scales as:
It’s sound is very bright and harmonious (I mean, it harmonises well and sounds good).
The Minor Third
The major third’s evil twin sounds much darker, sadder and some people would say “melancholic”. Here is the tab (C to Eb this time)
Notable scales that use the minor third include:
- The Natural Minor Scale (or the Aeolian mode)
- The Harmonic Minor
- The Melodic Minor
- The Minor Pentatonic
- The Dorian Mode
Playing thirds over chords is almost always a good idea- just make sure you play the right third (major or minor) over the right chords. So major thirds over major chords and minor thirds over minor chords…that’s not always the rule though, you need to experiment!
Don’t forget that bending the minor third up one fret to make it a major third can sound cool too!