Western music uses the letters A to G to represent notes of varying pitches. If we ascend A, B, C D, E, F, G we end up at A again and repeat the cycle. The second A is said to be one ‘octave’ above the previous A. In scientific terms the higher A is double the vibrational frequency of the lower A.
One octave is divided into 12 equal intervals. Each interval is said to be one half step. Between each letter are two half steps except between B to C, and E to F.
We use the symbol of a # to raise the pitch one half step. So one half step above A is A#, one half step above C is C#, one half step above D is D#, one half step above F is F#, and one half step above G is G#. We don’t have a sharp between E to F, or B to C because they’re already a half step apart.
We use the symbol of b to lower the pitch one half step. So descending from A we have Ab, from G to Gb, E to Eb, D to Db, and B to Bb. We don’t have a flat between E to F, or B to C because they’re already a half step apart.
We can represent these notes on a musical staff. A staff is a series of 5 lines and 4 spaces with symbols on it, that allow people to translate these symbols into musical notes. The lines are the notes E-G-B-D-F (bottom to top line) and the space are F-A-C-E (bottom to top space).
A scale is a series of notes within one octave. Let’s start with the major scale. A major scale is built by using a specific formula of half steps (1 fret) and whole steps (2 frets). This formula is (H = half step, W = whole step) W W H W W W H. If we start on the note C, this gives us the notes C D E F G A B C. Note we end up at C again but this C is one octave higher than the first C we started with.
Also note that between the notes C to D, D to E, F to G, G to A there is a note (fret) in between, but between E to F and B to C there is no note in between. Please see the diagram below:
You can also see this below on a piano where there are 2 white keys next to each other with no black key in between. The two adjacent white keys to the right of the group of 2 black keys are the notes E and F. The two adjacent white keys to the right of the group of 3 black keys are the notes B and C.
If we start with D as the root note and follow the same formula, we get D, E, F#, G, A, B, C# and D. We need the sharps to keep the proper series of whole steps and half steps in the major scale formula. A sharp is an accidental, which raises the pitch of a note a half step. Please see the following diagram:
Did you notice anything about this scale pattern compared to C major? I’ll wait while you take another look……On the guitar the D major scale has the exact same shape as C major just shifted up 2 frets. This information is key to understanding the layout of the fretboard. Here’s your rule of thumb: Take any chord, scale, riff, sequence with no open strings that works in a given key and just shift it up or down by the difference in keys to make it work in another key. Note: Make sure you don’t have any open strings in your riff/chord because if you shift it up to another key, the open string wouldn’t get shifted up properly unless you figure out a way to fret it with another finger in which case the shape/pattern would be altered.
A note about accidentals:
To raise the note C a half step you add a sharp making it C#. A flat is also an accidental which lowers a note a half step. To lower the note D a half step, you add a flat making it Db. Note that C# has the same pitch as Db – which is known as an enharmonic equivalent. All you need to remember is that certain keys have sharps and certain keys have flats. Keys with sharps are G, D, A, E and B. Keys with flats are F, Bb, Eb, Ab, Db and Gb. It’s just something you have to memorize.