What Are Intervals?
An interval is a measurement/unit of musical distance. The smallest interval we have in western music is a semitone, which is the distance between two notes played one fret apart from each other on the bass. The next interval up is a tone, which is a distance of two frets. A series of tones and semitones can be put together to create a scale. The major scale is constructed using the following sequence:
Tone, Tone, Semitone, Tone, Tone, Tone, Semitone
If we apply this sequence starting from C, we get the C major scale:
Make sure you memorise the shape of this pattern as it can be moved all around the neck to create a major scale in every key.
Intervals Within The Major Scale
To begin with, let’s number the notes in the major scale:
C D E F G A B C
1 2 3 4 5 6 7 8
These numbers are referred to as scale degrees and we can use them to describe melodies and bass lines with reference to which notes of the scale or key are being used. Here are the degrees of the C major scale again with the notation:
The major scale is classed as a seven-note scale, even though we play eight. This is becuase the scale begins and ends on the same note – the tonic.
So, going back to the intervals within the major scale. We keep the number degrees the same as above but add one extra word to each interval. The first, fourth and fifth degrees become perfect – perfect unison, perfect fourth and perfect fifth. The rest become major intervals – major second, major third, major sixth and major seventh.
Knowing and recognising these intervals will have a profound effect on the speed at which you learn. They will form the basis of everything you learn from basic basslines to advanced music theory.
A good exercise for learning the shape and sound of the intervals is to take an interval and play it over and over, going up one fret each time and then coming back the same way once you reach the 12th fret. Do this with every interval until you feel confident about how it sounds and feels.
Don’t worry about doing too much too fast – it is much more important to get the shape under your fingers first.
Melodic or harmonic intervals?
Intervals can be referred to in two different ways – melodic and harmonic. A harmonic interval is when two notes are played at the same time and a melodic interval is when they are played one after the other.