Definition: Note is used to represent the relative pitch and the duration of sound. A note in 3JCN has 3 components: octave position, name, and duration.
(Pitch represents the perceived fundamental frequency of a sound) (Duration: A tone may be sustained for varying lengths of time) There are total 128 notes for all music instruments (Standard MIDI notes as picture below).
Two notes with fundamental frequencies in a ratio of any power of two (e.g. half, twice, or four times) are perceived as very similar. Because of that, all notes with these kinds of relations can be grouped under the same pitch class.
1. Note's name: Seven lower case alphabet letters a, b, c, d, e, f, and g are used to represent notes La, Si (Ti), Do, Re, Mi, Fa, and Sol. There are plus notes and minus notes: a+ = -b c+ = -d d+ = -e f+ = -g g+ = -a (readTones and Semitones)
2. Note's duration: A real number followed a note's name is used to show the note's duration in number of units which is related to "beat" (depends on Time Signature).
For Time Signature with denominator 4 (such as 1/4; 2/4; 3/4; 4/4; 5/4; ...), then 1 unit = 1 beat. For Time Signature with denominator 2 (such as 1/2; 2/2; 3/2; ...), then 2 unit = 1 beat. For Time Signature with denominator 8 (such as 1/8; 2/8; 3/8; 4/8; 5/8; 6/8; ...), then 1.5 unit = 1 beat.
Examples: a2 --- > note La (A) with duration 2 (1 beat in time signature 2/2, 2 beats in TS 3/4,...) d3 ----> note Re (D) with duration 3 (3 beats in time signature: 2/4, 2 beats in TS 6/8, ...) c1.5 ---- > note Do (C) with duration 1.5 (1.5 beats in time signature: 3/4; 1 beat in TS 3/8, ...)
3. Note's Position: How to differentiate note Do in 3rd octave and note Do in 5th octave? It is very simple: We add a number in front of a note to show which octave the note belongs to.
For examples: 3c2 = note Do in 3rd octave (C3) with duration 2. 5c2 = note Do in 5th octave(C5) with duration 2. 2d1 = note Re in 2nd octave (C2) with duration 1. 9a3 = note La in 4th octave (C9) with duration 3
There are 11 octaves (1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and 11). Middle octave is 6th octave. For default, it's not necessary to write number 6 in front of middle octave note. (for example: "c2" stands for middle C with duration 2 beats). Why 6th? There are 128 notes in MIDI range. Each octave contains 12 notes (C, +C, D, +D, E, F, +F, G, +G, A, +A, and B) except the last octave (10th) has only 8 notes [C, +C, D, +D, E, F, +F, G]. So there are about 11 octaves. Middle octave is 6th.
Attention: 3JCN octave starts from C because each pattern on the keyboard of a piano starts from C
Every music instrument has its own range of octaves. Look at the bottom of picture below, you will see the standard 3JCN music range from octave 1 to octave 11. Note C, which starts 6th octave, is called middle C (MIDI order number of middle C is #60).