Intervals are the building blocks of chords. An interval
is the distance in pitch between any two notes. When you play
any two notes on the guitar at the same time you are playing a
harmonic interval. If you play a series of two or
more notes, one at a time, one after another you are playing a
melodic interval. A chord is defined
as three or more different notes or pitches sounding simultaneously.
Chords are sometimes named after the type of intervals they contain.
The introduction of intervals to your study of music theory,
at first will seem quite tough. From my own experience, do not
try to memorize all of the terms and definitions at once, the
more you study the construction of chords and scales your vocabulary
and understanding will increase naturally.
The first step is to understand some very simple terminology,
such as tones, semi-tones, whole-steps and half-steps. In relation
to the guitar fretboard, a semi-tone, also called a half-step
is equal to one fret. The difference between the A note at the
5th fret on the 6th string and the A# or Bb on 6th fret of the
6th string is one semi-tone or one half-step. Tones or whole-steps
follow the same logic, except they are both double the distance
or 2 frets.
The major diatonic scale is made of seven intervals, five tones
or whole-steps and two semi-tones or half-steps. The names of
the intervals consist of two parts, the quality and a number.
The quality describes the type of interval and the number tells
you the number of degrees spanned by the interval. In the chart
below the span always begins with the root note, C. Compound
Intervals are those which span more than one octave.
The Sound Characteristic is described as either
consonance or dissonance. Consonance
in an interval means stability and a pleasant sound, whereas dissonance
would be unstable and rough with a need to be resolved to a stable
consonance. The amount of dissonance increases as the distance
between two tones decrease. That is why on the chart below the
sharp dissonance occurs near the root note C and the C note one
octave above the root.
An interval is often inverted, this means raising
the lower note (C in the chart below) one octave. The number of
an interval and the inverted interval always total 9. For example,
the inversion of a 2nd interval is a 7th interval. The quality
of the interval also has a pattern. A minor inverts to a major
(and vice versa). A perfect remains a perfect. An augmented inverts
to a diminished (and vice versa). A double augmented inverts to
a double diminished (and vice versa).
Click on the thumbnail below for a full size interval chart.
