The chromatic scale is the fundamental and essential scale of the Western musical system. It is defined as a succession of 12 pitches a semitone apart from each other leading up to the repetition of the first pitch at the next higher octave. But what is a semitone? And what is an octave?
A semitone is the minimum distance between two sounds in the Western musical system (things are different, for example, in Eastern countries such as India). If you press a white key on the piano and the black key innediately next to it, you will have played an interval of 1 semitone. On the guitar, however, each fret that divides the fretboard corresponds to 1 semitone.
So ,when we say that between the notes C and D there is an interval (i.e a distance) of one tone, it means that there are 2 semitones between those notes. Press any C on the piano and then play, moving to the right, the very next black key, and then the very next white one; you will have arrived at the note D by stepping up 2 semitones.
So 1 tone = 2 semitones.
Similarly, if we consider 2 tones we can think them as corresponding to 4 semitones.
Do you know this symbol: #? In music, it’s called ‘sharp’ and indicates that a sound has been raised by just one semitone. So C# means that a C note has been raised by a semitone. The same goes for D and D# or G and G#, but E and F are already one semitone apart; therefore, stepping between these two notes, we will not have E and E#, but just E and then directly F. The same happens for the notes B and C.
Let’s look at chromatic scale on a piano keyboard:
The black keys indicate precisely the notes raised by a semitone.
As we have seen above, when the chromatic scale descends (i.e. from high to low), another symbol written as follows is used: b (called ‘flat’). It has the opposite meaning to that of the sharp, i.e. it lowers the note by a semitone. So if we move from C to D we will have C# (C plus half a tone) but if we go down from D to C we will have Db (D minus half a tone). Hence, a note with the same pitch can have two different names, as you can see in the following figure:
Finally, we can say that the chromatic scale, like all scales, is cyclical: this means that once the sequence of twelve semitones has ended, it can in theory repeat itself infinitely in both directions:
…C C# D D# E F F# G G# A A# B C C# D D# E F# G G# A A# B C… On the staff, it would look like this:
We conclude by saying that the writing the chromatic scale on the staff highlights the fact that the name of the notes repeats cyclically but in different points of the staff, and this has a very different musical meaning which should never be mistaken. In other words, although you meet a note called ‘C’ several times (and the same applies to any other note) on different places of the staff, even though their name does not change, their sound does. In fact, we speak of higher C and lower C.
So, in your opinion, how many semitones, in all, do you think correspond to 3 tones and 1 semitone?
Now let’s go back to our chromatic scale. On the score we can write it like this:
Which, in ascending order, reads: C C# D D# E F F# G G# La A# B C
and descending we read: C Si B Sib Bb A Ab G Solb Gb F E Eb D Reb Db C
If we count, the sounds notes of this scale are 12 plus the repetition of the first sound note (C) at the higher octave. But what does upper octave mean? If you try to say theread aloud the notes that make up the C (major) scale aloud, you will say: Do C D Mi E Fa Sol G A B C. That last C is repeated after 7 notes and it becomes the eighth note (i.e. more acutehigher than the first C) and for this reason called superior higher octave.
Here’s how the this octave interval looks on the scorestaff:
Let’s repeat: between the lower C and the higher one you will count 8 notes.