Music Interval

Fundamental knowledge for understanding Music Codes

Posted by Sponge K. on September 24, 2019

If you are a hobbyist musician/composer, you may hear music codes. Nowadays there are many ways to enjoy music, you may play/compose with ordinary raw instruments and also with Apps of iPhone/Android. And if you have a bit additional knowledge of theory: code, your sense of music will jump up to the next height.

This article provides you minimum but enough information of Music Interval, which will be a fundamental knowledge to understand Code. It is not written for Berklee students but for you as a hobbyist. So there's no hassle! Important numbers you should pay attention are written in Italic font. The way to understand is like reading a series of tale. Let's start!

Names of Notes

There are 12 Keys and Notes. Name of the note starts from "C".

C D E F G A B
C
D
D
E
F
G
G
A
A
B

White Keys

There are 7 Principal Notes.

C D E F G A B

Black Keys

There are 5 Derived Notes .

C D F G A
(D) (E) (G) (A) (B)

How to count Notes

1. Interval of Notes

Assume interval to itself as "1", which is called "Unizon", and increased by principal note. Each number of interval is called like below.

1: Unizon
2: Second
3: Third
4: Fourth
5: Fifth
6: Sixth
7: Seventh
8: Octave

Ordinal numbers are used for 2 to 7. As there are only 7 Principal Notes, therefore when it comes to 8: Octave, note starts again from "C".

Table1: Intervals of Notes
CDEFGABCD
C123456789
D12345678
E1234567
F 123456
G12345
A1234
B123
C12
D1

2. Distance of Notes

There is another way to count notes. Intervals written upon were numbers counting only Principal Notes. It was simple and easy to understand, but ignored rest 5 Derived Notes.

To count up all 12 notes in simple way, we use Distance of Notes. A unit of distance betwee 2 notes next to each other is defined as "Half Step" (half tone).

Half Step × 2 = Whole Step

C C
D
D D
E
E F F
G
G G
A
A A
B
B

  • C-D: 2 Half Steps (= Whole Step)
  • E-F : 1 Half Step

Table below is a list of all 12 keys and distances from Principal (root) Notes.

Table2: Distance of Notes
Root: CInterval & Distance(+,-)
C1: Unison
C (D)+1-1
D2: Second
D (E)+1-1
E3 :Third
F4: Fourth
F (G)+1-1
G5: Fifth
G (A)+1-1
A6: Sixth
A (B)+1-1
B7: Seventh
C8: Octave

3. Naming

If interval is 1, 4, 5, (8) add prefix: Perfect. If interval is 2, 3, 6, 7 add prefix: Major. Start from either Perfect or Major, name of interval is decided by distance of step (+/-) .

The chart below is normally written upside-down in many music specialized books and web sites. But to refer it with followed "Table3: Example of Interval Names", I express diminished upside, and Augmented downside.

diminished
-1-1
minor
-1
Perfect
1, 4, 5, (8)
Major
2, 3, 6, 7
+1+1
Augmented

Table3: Example of Interval Names
C Perfect Unison (P1)
C
(D)
Augumented Unison (A1)
minor 2nd (m2)
DMajor 2nd (M2)
D
(E)
Augumented 2nd (A2)
minor 3rd (m3)
EMajor 3rd (M3)
FPerfect 4th (P4)
F
(G)
Augumented 4th (A4)
diminished 5th (d5)
G Perfect Fifth (P5)
G
(A)
Augumented 5th (A5)
minor 6th (m6)
AMajor 6th (M6)
A
(B)
Augumented 6th (A6)
minor 7th (m7)
BMajor 7th (M7)
CPerfect Octave (P8)

I found a description to clarify naming rule of Intervals. ("without changing its numerical name" is important to remember, underlined in quotation below.)

The term perfect is only used in connection with unisons, fourths, fifths, and octaves. The terms major and minor are only used in connection with seconds, thirds, sixths, and sevenths. If a major interval is made a half step smaller without changing its numerical name, it becomes a minor interval. If a minor or a perfect interval is made a half step smaller without changing its numerical name, it becomes a diminished interval. If a minor interval is made a half step larger without changing its interval name, it becomes a major interval. If a major or a perfect interval is made a half step larger without changing its numerical name, it becomes an augmented interval.

Cited from "Basic Music Theory" by Larry Konecky

I hope you can understand Interval of Music, now. In next article I want to post "Music Codes and those Progression".