A
musical interval is the distance between two notes. The distance
is measured in semitones. A semitone is the smallest interval
measured in western musical theory.
The
International Note
Names are A A# B
C C# D D# E F F#
G G#
The same Latin Note
names are LA LA#
SI DO DO# RE RE#
MI FA FA# SOL SOL#
Example : the interval between
C and C# is a semitone,
the interval between
E and F is a semitone.
A
tone is an interval
that is equal to
two semitones. For
example, the interval
between C and D
is a tone, and the
interval between
E and F# is a tone
and so on.
When
about constructions
of chords / melodies,
tones and semitines
have other names
: the interval between
any two consecutive
letter names is
called a 'second'.
Then, from A to
B is a second. The
interval between
two notes with an
extra one in-between
is called a 'third'.
So from A to C is
a third. This continues
as follows:
A
to A (same note/frequency)
: unison
A
to B :
the second
From
A to B is a second.
There is one note
in-between A and
B, called either
A# (also called
Bb).
Therefore there
are 2 semitones(=
a tone) between
the notes A and
B.
Therefore it is
said to be a 'major'
second.
Then,
a major second is
equal to a tone.
From
A to Bb is a second.
(because it is two
consecutive letter
names, even if one's
a flat)
There are no notes
between A and Bb.
Therefore there
is 1 semitone between
the notes A and
Bb.
Therefore it is
said to be a 'minor'
second.
Then,
a minor second is
equal to a semitone.
A
to C : the
third
From
A to C# is a third.
There are 3 notes
in-between A and
C#. They are: A#,
B and C.
Therefore there
are 4 semitones
between A and C#.
Therefore
it is said to be
an interval of a
major third.
From
A to C is a third.
There are 2 notes
in-between A and
C#. They are A#
and B.
Therefore there
are 3 semitones
between A and C.
Therefore
it is said to be
an interval of a
minor third.
A
to D : the
fourth
A to E
: the fifth
Moving
on to the interval
of a fourth and
fifth, things change.
There are no major
or minor fourths.
The qualities that
can be applied to
a fourth are 'perfect',
'diminished', and
'augmented'. A perfect
fourth contains
5 semitones, as
in C to F. An augmented
fourth contains
6 semitones, as
in C to F#. A diminished
fourth contains
4 semitones, as
in C# to F. From
this, we can see
that diminished
intervals are smaller
than perfect intervals,
and perfect intervals
are smaller than
augmented intervals.
The
qualities of 'perfect',
'diminished' and
'augmented' are
only applied to
fourths, fifths.
Octaves and unisons
have only one quality,
and that is perfect.
A
to F
: the sixth (like
the second and third,
it is either minor
or major)
A to G
: the seventh (like
the second and third,
it is either minor
or major)
A to A (from lower
to higher A) : the
octave (only perfect)
No
need to memorize
the number of semitones
in each interval
(...) the following
chart summerizes
it :
|
(p
= perfect,
m = minor,
M = major,
dim = diminished,
aug = augmented)
:
|
|
Interval
:
|
Number
of semitones
|
Example,
taking C
as first
note :
|
|
perfect
unison /
p1
|
0
semitones
|
C
to C
|
|
minor
second /
m2
|
1 semitones
|
C
to C#
|
|
major
second /
M2
|
2 semitones
|
C
to D
|
|
minor
third /
m3
|
3
semitones
|
C
to Eb
|
|
Major
third /
M3
|
4
semitones
|
C
to E
|
|
diminished
fourth /
dim4
|
4
semitones
|
C#
to F
|
|
perfect
fourth
/ p4
|
5
semitones
|
C
to F
|
|
augmented
fourth /
aug4
|
6
semitones
|
C
to F#
|
|
diminished
fifth /
dim5
|
6
semitones
|
C
to Gb
|
|
perfect
fifth /
p5
|
7
semitones
|
C
to G
|
|
augmented
fifth /
aug5
|
8
semitones
|
C
to G#
|
|
minor
sixth /
m6
|
8
semitones
|
C
to Ab
|
|
major
sixth /
M6
|
9
semitones
|
C
to A
|
|
minor
seventh
/ m7
|
10
semitones
|
C
to Bb
|
|
major
seventh
/ M7
|
11
semitones
|
C
to B
|
|
perfect
octave /
p8
|
12
semitones
|
C
to C (the
next higher
one)
|
Please
notice that some
have the same number
of semitones, but
are named different
intervals : Some
intervals have two
names. |
