While music may seem like a very complex thing, it is derived from only 12 musical notes. If you want to play music, you must understand how these notes work, since notes are the ‘building blocks” of music. This lesson will give you a basic understanding of the 12 notes used in western music.
These notes are divided into two groups: naturals and accidentals.
Naturals
If you are familiar with the piano, natural notes are the white keys on the piano keyboard. These notes are assigned to the first 7 letters of the alphabet:
A B C D E F G
Accidentals
The remaining 5 notes are placed between the natural notes above. Accidentals are the black keys on the piano keyboard, and are called “sharps” (denoted by a # sign) or “flats” (denoted by a “b” sign). I paired the notes together below because they are actually the same note, although they can be written either way for reasons we’ll see soon. The note “Ab” would be pronounced “A flat” while the note A# would be pronounced “A sharp.”
A#/Bb C#/Db D#/Eb F#/Gb G#/Ab
The Chromatic Scale
Put all of your naturals and accidentals together in alphabetical order, and you’ve got the complete 12-note scale (also called the Chromatic Scale). This scale is the root of all western music, so the sooner you memorize it the better!
A A#/Bb B C C#/Db D D#/Eb E F F#/Gb G G#/Ab
½ Step Forward, ½ Step Back
Western music divides its pitches into ½ step intervals; that is, each of the notes above is separated in pitch by ½ step. The keys on a piano and the frets on your guitar are placed at ½ step intervals as well, so if you were to start on your open A string and play it on each fret (starting open, then 1st fret, then 2nd, then 3rd, etc) you would be playing the notes of the chromatic scale exactly as written above. (Instruments used in Asian and Middle Eastern cultures may use ¼ step or other odd intervals, which gives that music a different sound).
An accidental is simply a ½ step different from the note next to it in the chromatic scale. A sharp (#) is ½ step higher, while a flat (b) is ½ step lower. So a D# note is ½ step (or one fret) higher than a D natural. A Db is ½ step (or one fret) lower than a D natural.
So you can see why an A# is the same note as a Bb by looking at your guitar’s fretboard. An A note is played with your A string open, while a B note is played with your A string on the second fret. That leaves one fret between your A and B notes. The note on that fret could be called an A# (because it’s ½ step higher than an A natural), or a Bb (because it’s ½ step lower than a B natural), but it’s the same note either way.
You may notice from the chromatic scale above that there are two pairs of notes which do not have an accidental between them (B and C, E and F). This means that, on a guitar, a C note is just one fret above a B note.
So that’s it: the 12 notes of western music. Have fun!