S2 Theory Concepts
Semi-tones and Tones
Look at the keyboard diagram below.
A semi-tone is the smallest step normally used in music – a step from one note to it’s
nearest neighbour (e.g. E – F, B –C.).
A tone is made up of 2 semitone steps (e.g. C – D, G – A).
C# D#
Db Eb
C
D
E
F#
Gb
F
G
G# A#
Ab Bb
A
B
C’
Sharps, Flats and Naturals
These are all signs that alter the pitch of a note.
A sharp (#) raises the pitch of a note by a semitone (e.g. F – F#, A –A#).
A flat (b) lowers the pitch of a note by a semitone (e.g. G – Gb, B –Bb).
A natural (
) cancels out a previous sharp or flat (e.g. F# - F or Bb – B).
Enharmonic Notes
The use of different letter names for notes of the same pitch is called enharmonic.
Look at the keyboard diagram above. You will see that the black notes can be thought
of as either sharps or flats. For example, F sharp is the same note as G flat, while B
flat is the same note as A sharp.
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S2 Theory Concepts
The Major Scale
Scales move up and down by step. The major scale is made up of tones and semitones.
All the steps are a tone apart except the 3rd and 4th notes and the 7th and 8th notes which
are a semitone apart.
The Minor Scale
The harmonic minor scale is made up of steps like the major scale but there are semitones
between 2nd and 3rd notes, the 5th and 6th and the 7th and 8th notes. The other notes are a
tome apart, except the 6th and 7th which has a gap one and a half tones.
Key Signatures
Key signatures are a series of sharps and flats written at the beginning of each line of
music (after the clef) to tell us what key the music is in and what sharps or flats to
use.
Look at the music below. The key of G major uses an F sharp (rather than a normal F)
while the key of F major uses a B flat (instead of B).
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S2 Theory Concepts
Intervals
An interval is the distance in pitch between two notes. Intervals have different sizes.
The size of an interval is worked out by counting the number of letter names it covers.
Both notes of an interval are included in the count. For example C – E is a 3rd since it
covers 3 letter names (C,D, E).
C – G is a 5th since it covers 5 letter names (C, D, E, F, G).
Chords and Triads
Two or more notes sounding at the same time make a chord. A triad is a chord of three
notes.
A triad can be built on any note of the scale.
C
D
E
F
G
A
B
C’
e.g. Triad of C major = C, E, G
The note a triad is built on is called the root (C).
The next note is called the 3rd as it is three notes away from the root (D).
The last note is called the 5th as it is five notes away from the root (D).
The Bass Clef
The bass clef is used for all the notes below Middle C (while the treble clef is used for
all the notes above middle C ). An easy way to remember the notes on the bass clef is
shown below:
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