Basic Music TheoryLesson 2: Constructing Key signatures

Cylent Beatz Production

A semitone or half step is the movement of sharpening or flattening a note.

C > C# C > Cb

A tone or whole step consists of two semitone steps.

C C > D C > B

Semitone and tone

Key signatures are constructed using a series of tones and semitones.

The order of which are determined by the quality of the scale. For example, whether it is major or minor.

A keyboard can help in working out the steps.

Constructing Key Signatures

The order of these steps for the major scale are:

T, T, S, T, T, T, S T = Tone S = Semitone

Using that formula to construct A major:

A – B - C# - D – E - F# - G# - A

Constructing Key Signatures

The order of these steps for the natural minor scale are:

T, S, T, T, S, T, T T = Tone S = Semitone

Using that formula to construct A minor:

A – B - C - D – E - F - G – A

There exist other minor scales.

Constructing Key Signatures

There are three minor scales, natural, harmonic and melodic.

The harmonic minor is the same as the natural minor scale except that the seventh degree is raised by a semitone.

So, A harmonic minor will be as follows:

A – B - C - D – E - F – G# – A

Minor Scales

For the melodic minor scale, take the natural minor and raise both the sixth degree and seventh degree by a semitone.

A melodic minor scale:

A – B - C - D – E – F# – G# – A

Minor Scales

Questions?