Basic Music Theory Explained

Here I want to give you a basic understanding of musical theory, but without overloading you with information. If you know your stuff as far as musical theory goes, you'll notice that I've left a lot out, and this has been done on purpose.


During this section, I'll be referring to chord names and interval names, so it's important that you understand what we're talking about. These are the chord names we'll be using:

Major Chord:

Any time you see a letter on it's own for example "F" you know we mean F Major. I also may write it as "F Maj", so either of these requires you play the Major chord.

Minor Chord:

If you see a letter followed by a little m Eg "Fm" then this relates to the minor chord. Again, I might write "F min", or "F minor", and either of these will refer to a minor chord.

There are literally hundreds of chords, and variations, but you will not need most of them in this course, and there are plenty of chord books and chord information on various websites available, so I will not cover them all here. The purpose of this course is to help you to compose music, not learn every chord in existence.

Flats and Sharps:

A flat note uses the symbol (b) and a sharp note uses the symbol (#).

The Octave:

An octave is a musical term that covers a total of 11 notes, and spans from one note, to the next note of the same name. The notes within the Western musical range are as follows:

A, B #, B #, B #, B #, B #, B #, B #

After the Ab, we end up at the A again. All the notes you'll ever play will be one of these. You'll notice that there are no sharps or flats between the notes B and C or E and F. There Are exceptions to this rule, but you will not need to learn them here.

The Major Scale:

The major scale is a series of seven notes that follow a particular order. The order is as follows:

1 2 3 4 5 6 7 (and back to) 1

Root – Tone – Tone – Semitone – Tone – Tone – Tone – Semitone

This scale is the basis for all musical theory. You would probably recognize it from your school days as:

Do – Re – Mi – Far – So – La – Ti – Do

The Minor Scale:

Each major key has a corresponding, relative minor key. The minor key will be in the same key signature, and will contain the same notes as the major key. The only difference between the two is that the minor key simply STARTS on a different note. For example, in the key of C Major, the relevant, corresponding minor key is A minor.

You can always find the relative minor key by counting up six notes from the root of the Major key. So in the C Major example: C, D, E, F, G, A, B, C. Here the minor key starts on the A.

The sequence of a minor scale is different, and goes like this:

Root – Tone – Semitone – Tone – Tone – Semitone – Tone – Tone

So if as an example we use the A minor scale which is the relative minor scale of C Major, we have the following sequence of notes:


If we were playing in F Major, the relative minor would again begin on the sixth note in the key, which would be the D, and the sequence of notes would be:


Key Signatures:

A semitone (or half step) is the smallest increment on a western musical instrument. On a piano, it is represented by moving from one key to the next, and on a guitar, it is represented by moving from one fret to the next.

As an example, on a piano, moving from middle C to the black key directly next to it on the right, we would get a C # and this would be a semitone. Moving from middle C to the next WHITE key on the right, which is the D, would be a tone from the middle C (also known as two semitones or a whole step).

On a guitar, moving from the open A string to the first fret on the A string A # would be a semitone, while moving from the open A string to the second fret B would be a tone (two semitones).

So if we look at the C Major scale, it looks like this:

C (root note)

Then up a TONE to D

Then up a TONE to E

Then up a SEMITONE to F

Then up a TONE to G

Then up a TONE to A

Then up a TONE to B

And finally up a SEMITONE again to finish back on C.

All major keys follow this pattern, and you can start a Major scale on any note.

A couple of things to be aware of: Some notes have the same sound, but different names depending on which KEY they are in. For example, an A # is the same note as a Bb as if you move up ONE semitone from A it becomes A # and if you move down ONE semitone from B it becomes a Bb. Again, you do not need to worry too much about this if it's confusing you as we're going to stick mainly to simple chords and keys through this book.


As a reference, here is a list of all the keys, the notes within them, and the chords within the key!

C Major:

Notes: C, D, E, F, G, A, B, C

Key signature: (No key signature)

Chords within Key: C, Dm, Em, F, G, Am, B eliminated

G Major:

Notes: G, A, B, C, D, E, F #, G

Key signature: One sharp on the F line

Chords Within Key: G, Am, Bm, C, D, Em, F # Diminished

D Major:

Notes: D, E, F #, G, A, B, C #, D

Key Signature: Two Sharps on the F line, and C line

Chords Within Key: D, Em, F # m, G, A, Bm, C # Diminished

A Major:

Notes: A, B, C #, D # E # F #, G #, A

Key Signature: Three sharps on the F line, C line, and G line

Chords Within Key: A, Bm, C # m, D, E, F # m, G # Diminished

E Major:

Notes: E, F #, G #, A, B, C #, D #, E

Key Signature: Four sharps on the F line, C line, G line, and D line

Chords within Key: E, F # m, G # m, A, B, C # m, D # Diminished

B Major:

Notes: B, C #, D #, E, F #, G #, A #, B

Key Signature: Five sharps on the F line, C line, G line, D line, and A line

Chords within Key: B, C # m, D # m, E, F #, G # m, A # Diminished

F # Major:

Notes: F #, G #, A #, B, C #, D #, E #, F #

Key Signature: Six sharps on the F line, C line, G line, D line, A line, and E line.

Chords within Key: F #, G # m, A # m, B, C #, D # m, E # Diminished

And Now The Flat Keys:

F Major:

Notes: F, G, A, Bb, C, D, E, F

Key Signature: One Flat on the B line

Chords within Key: F, Gm, Am, Bb, C, Dm, E Diminished

Bb Major:

Notes: Bb, C, D, Eb, F, G, A

Key Signature: Two flats on the B line and the E line

Chords within Key: Bb, Cm, Dm, Eb, F, Gm, A Diminished

Eb Major:

Notes: Eb, F, G, Ab, Bb, C, D, Eb

Key Signature: Three flats on the B line, E line, and A line

Chords within Key: Eb, Fm, Gm, Ab, Bb, Cm, D Diminished

Ab Major:

Notes: Ab, Bb, C, Db, Eb, F, G, Ab

Key Signature: Four flats on the B line, E line, A line, and D line

Chords within Key: Ab, Bbm, Cm, Db, Eb, Fm, G Diminished

Db Major:

Notes: Db, Eb, F, Gb, Ab, Bb, C, Db

Key Signature: Five flats on the B line, E line, A line, D line, and G line.

Chords within Key: Db, Ebm, Fm, Gb, Ab, Bbm, C Diminished.

Intervals and chords:

Without covering the gamut of musical theory, I want you to have a basic understanding of intervals and chord structure. An interval is simply the difference between one note and another, in particular how they relate to each other in a particular key.

If we start in the key of C Major as it's the easiest key, with no sharps or flats. If we move from C to C #, that interval is a Semitone. This equates to one fret on the guitar, or one key on the piano. If we move from C to D, that is a TONE. 2 frets, or two keys.

Below is a table keeping a list of the intervals available if we start on the note C:

The interviews will follow this format:

Original note:

New note:

Interval name:

Number of Keys / frets / Semitones higher than original note:


C # / Db

Semitone (minor 2 nd)




Tone (Major 2nd)



D # / Eb

Minor 3 rd




Major 3 rd




Perfect 4 th



F # / Gb

Augmented 4 th / diminished 5 th




Perfect 5 th



G # / Ab

Augmented 5 th / Minor 6 th




Major 6 th



A # / Bb

Minor 7 th




Major 7 th






I've listed the interviews only in the Key of C Major here.

This is the same for all keys. So if for example you were playing in Bb Major, and you wanted to find the Major 3 rd, you just count up five semitones (frets or keys) and you'll land on D. Always take the root note (the one you ' re starting on) as number 1.

Quick Test:

A) What is the minor 3 rd from G?

B) What is the Perfect 4th of Eb?




If you get these wrong, go over this section again, but do not spend too much time on it, you'll begin to understand it a little more as we go along, and it's just a matter of counting up the keys or frets .

The Structure Of Chords:

Now we come on to chords. Again, without going too much into depth, MOST chords are made up of three notes, which is the root of the chord, the third, and the fifth. For example, if we take C major again, and write out the scale:

C, D, E, F, G, A, B, C, and attribute a number to each of the letters

1, 2, 3, 4, 5, 6, 7, 1

This is what we end up with. So if we take the numbers 1, 3, and 5, we get the letters C, E, and G. These are the notes that make up a C chord.

Taking the second chord in C major (See Key section above), we have a Dm chord. This time, as D is the ROOT note, we class D as number 1, and count up again.

So D becomes 1, F becomes 3, and A becomes 5 and so on. This is how nearly all chords are formed; again, you need not worry TOO much about this, as you will not need to know it in great detail.

What notes make up an F Major chord?



Musical Timing:

The purpose of a time signature is to show you what type of feel, rhythm, and speed you should play certain notes, phrases and bars.

There are various time signatures in music. The two most common are Four-Four time, and Three- Four time.

The first number in the time signature denotes the NUMBER of notes you will be playing, PER BAR and the second number tells you what TYPE of note you'll be playing.

So if we're playing in Four-Four time, you would have four even beats of quarter notes, and count like this: One, Two, Three, Four, One, Two Three, Four etc.

If you were playing in three four time, you'd be using the same length notes, but only count three of them per bar, for example: One, Two, Three, One, Two, Three etc.

The following are the most common types of note found in Western music, and each of these notes also has a corresponding rest that has the same duration. These are also found on the examples below.


These last for a full count of four beats and would normally last a whole bar in Four-Four time.


These last for two beats each, also known as a half note as each one of these notes lies for half a bar in 4/4 time.


These last for one beat each and are also known as a quarter note as each one of these notes lies for a quarter of a bar in 4/4 time.


These last for half a beat each and are also known as an 8 th note as each of these lasts for an 8 th of a bar in 4/4 time.


These last for a quarter of a beat each and arealso known as a 16 th note as each one lasts a 16 th of a bar in 4/4 time.

As I mentioned, there is a lot that I have left out when it comes to timing, and again, this is done on purpose as you will not need to get any more complicated during this course.

Dotted Notes:

If there is a dot directly next to the note, that means that it lasts HALF AGAIN the value of itself.
For example, if you have a dotted Minim, it will last for three beats as 2 (the normal value of a minim) + 1 (half the value of the minim) = 3.

There are other time signatures, and note values ​​but we do not need to go into them here.

What we've covered:

Key signatures

The Major scale


Basic chord theory


You now have a reference to use as and when you need it.

Source by Simon Allan Smith

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