David Loberg Code, Western Michigan University
The space between any two
pitches is called an interval.
Whole steps and half steps are two types of intervals. A whole step can also be called a major
2nd, and half steps are sometimes called minor 2nds. Major simply means BIG; minor
means little. The
number 2 (2nd) comes from counting the number of letters from one
note to another. Bigger intervals
can also be identified by their interval count (or size) and quality (major, minor, etc.).
When counting, always
start on 1 (never zero). For
example, the interval count from D to B is a 6th:
D (1) – E (2) – F (3) – G (4)
– A (5) – B (6)
Instead of counting letter
names, you can also count the number of lines and spaces on the staff (still
starting with 1). The answer
should be the same. By the way, a
count of 1 is called a unison or a prime, and a count of 8 is called an octave
(instead of an 8th).
Also, when counting, it doesn't matter whether or not there are any
sharps or flats. D# to B is also 6th;
so is D to Bb, or Db to B#, and so on.
The differences between these various kinds of 6ths is called
the interval quality. You might
think of them as different flavors of 6ths.
As another example, A to C
has the same interval count as A to C#: they are both 3rds. However A to C# is a BIGGER 3rd
than A to C, so they have different interval qualities. Not surprisingly, the BIG 3rd
is called a major third and the little 3rd
is called a minor third (just like with major and minor 2nds). Unfortunately, there is more than just
major and minor. Other interval
qualities include perfect, augmented, and diminished.
Finding the interval count
is easy enough, but how do you figure out what the interval quality is supposed to be? The simplest way is to go back to the major scale. Taking the intervals from the starting
note (Do) to each successive scale degree we get the following intervals:
From Do toŠ
Do Re Mi Fa So La Ti Do
Perfect
1 Major 2nd
Major 3rd Perfect 4th
Perfect 5th Major 6th
Major 7th Perfect 8ve
Notice that the second,
third, sixth, and seventh are all major intervals. (That is why it is called a major
scale.) The unison, fourth, fifth,
and octave are all perfect.
You can find out why they are these qualities another day, but for now
just remember:
In a major scale
1,4, 5, and 8 are always Perfect
2,
3, 6, and 7 are always Major
(There is NEVER such a
thing as a Major 5th or a Perfect 3rd.)
So, to figure out the
interval between two notes:
1. Pretend that the bottom note is the first note (Do) of a major scale. (Write out the scale if you need to or finger it on your instrument.)
2. Is
the top note already in the scale?
If yes, then you already know what the interval is. Just count up the number of notes and
add the name of the quality (either major or perfect).
Let's
try the interval from G up to E.
The G major scale is: G A B C D E F# G
E
is in the scale. It is the 6th
scale degree.
The
6th scale degree is always major.
G to E is a Major 6th.
3. If the exact note is not in the scale, you will need to adjust the interval quality. If your note is a half step lower than the major interval in the scale, the quality will be minor. For example:
Let's
try the interval from D up to F.
The D major scale is: D E F# G A B C# D
D
to F# is a major 3rd. F
is a half step lower.
D to F is a Minor 3rd.
For other qualities, use
the following adjustment chart starting from either a perfect or major
interval:
Diminished < Perfect <
Augmented
or
Diminished < Minor < Major < Augmented
-2 half steps -
half step +
half step
Let's
try the interval from F to B.
The F major scale is: F G A Bb C D E F
F
to Bb is a perfect 4th. B is a
half step higher.
F to B is an Augmented 4th.
4. What if I can't make a major scale using the
bottom note? No problem, you can
use the same method of adjusting the quality in reverse.
Let's try the interval from C# to E.
I don't like C# major, so I'll spell a C major scale instead.
The
C major scale is: C D E F G A B C.
C to E is a major 3rd.
C# to E will shrink the size by a half step.
C# to E is a minor 3rd.