Music theory part 1

OK this is the first music theory post. I will try to keep to the important parts that pertain to my discussions on songwriting. The main points I will discuss are scales, intervals, and chords. This post will discuss scales. He we go...

The basic tonal building block in Western music is the note. There are 12 note names and these note names repeat over and over again and each of these cycles is called an octave. This series of twelve notes is called a chromatic scale. If you look at a piano each key is a note. The note names are:

A A# B C C# D D# E F F# G G#
Bb Db Eb Gb Ab

So what are are those '#' and 'b' symbols. They are called sharps and flats and they increase or decrease a note by a semi-tone or half step (this will be discussed later in the interval section). The sharps and flats correspond to the black keys on a piano. I guess you are asking at this point why have letter names in combination with sharps and flats instead of just using only letter names and why have both sharps and flats when they look redundant? Well this has to do with the construction of scales.

Ok, what is a scale? A scale is a subset of notes that when played impart a particular sound to the music. Scales in traditional Western music generally consist of seven notes and repeat at the octave. Notes in the commonly used scales are separated by whole and half step intervals of tones and semitones. These seven note scales are called diatonic scales.

Ok but why are there sharps and flats. That's because the way diatonic scales are constructed, they contain every letter and each letter is represented only once in the scale (ie, a scale cannot contain an A and an A#). Why you ask.... because it is a convenient way to define diatonic scales. Seven notes in the scale and seven letters representing the notes, isn't that a coincidence. If a scale has an A and an A# then the A# is actually a Bb.

So how do you determine what notes are in a scale. Well it starts with the C note. If you start at C and progress through the letters with no sharps and flats, you have what's called the Major scale. The C Major scale contains the notes C-D-E-F-G-A-B and if you look at the list of notes you see that this scale by starting at a note and use the following progression

w-w-h-w-w-w-h

Where 'h' is a half step and 'w' is a whole step (two half steps)

You can now form a major scale in any key using this progression. Wait, hold on a minute... what is a key? Its just the note you started the progression on (and is also called the root note). So a specific scale is identified by the key and the type of scale (for example the major scale that is in the key of C is called the C Major scale or in the key of C Major). If no scale type is given, it is assumed to be the major scale (e.g., in the key of C really means in the key of C Major).

Now let's try this in the key of A

A B C# D E F# G# A
w w h w w w h

Now let's try this in the key of F (using sharps)

F G A A# C D E F
w w h w w w h

Since this scale has two A notes (A and A#) so we replace the A# with Bb. That is why we have both sharps and flats. Also another rule for thumb for the diatonic scales is that the notes in the scale can contain sharps or flats but not both.

So what are the different diatonic scales? Well they are defined by starting on a different note and progressing through the letters with no sharps or flats. The different scales formed using this method are called modes. Here are the seven scales (modes) that are possible.

In this table s is a half step T is a whole step and the white note is the start of the scale. The two most import scales are the Ionian scale which is also called the Major scale and the Aeolian scale which is also called the minor scale. You can use interval sequence from the table to form any scale in any key.

There is one other concept that is important to musical scales and that is the circle of fifths. The Circle of Fifths chart used in music theory shows the relationships among the twelve tones of the Chromatic Scale, their corresponding number of sharps or flats in the key, and the associated Major and Minor keys.

At the top of the Circle Of Fifths diagram, the key of C has no sharps or flats. Starting from there and going clockwise by ascending fifths (an interval that spans five notes in a diatonic scale), the key of G has one sharp, the key of D has 2 sharps, and so on. Going counterclockwise from the top by descending fourths (an interval that spans four notes in a diatonic scale), the key of F has one flat, the key of B♭ has 2 flats, and so on. The circle is commonly used to represent the relationship between diatonic scales. Adjacent keys on the circle of fifths represent Diatonic Scales that are a perfect fifth apart and share six of their seven notes. Furthermore, the notes not held in common differ by only a semitone. Thus moving to a new scale by a perfect fifth can be accomplished in a very musical fashion.

I hope that gives you a good introduction to the concept of scales. The next music theory post will describe the basics of intervals and chords. Until then enjoy...