B5 - 04 Music Theory- What is a 'Key'?

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Pop songs are always in a ‘key’. This means they use certain chords that go together well, which are derived from corresponding the major scale. Music teachers always explain the key of C first as it has no nasty ‘sharps’ of ‘flats’.

Chords in Key of C

These chords can be seen like colours that go together well- meaning any of these are a safe choice and a song in the key of C would mainly use these chords and few others, if any. As well as the chords, we can play notes from the C major scale (next page) over the top of these for the melody

Chords + melody = song

Example chord sequences in the ‘Key Of C’

#1 - Begins on C and resolves on the tonic (aka sounds finished)

This resolve can be heard because we are starting and finishing on the key aka the tonic chord.

|C                  |Am                   |F                   |C                   |

#2 - Begins on C but is left unresolved on the G (aka sounds unfinished)

This unresolved sound is a great example of tension in music. Tension and release is an underlying principal to why sounds sound great and others just don't. 

|C                  |Am                   |D                   |G                   |

N.B. The info on cadences that I talk about in the video above differs somewhat to their dictionary definitions. This was chosen to communicate the heading of the key of a song to beginners, while being helpful at understanding keys. More to come on cadences in the future! 

For further reading on this topic, you can learn about the key of G in this video here.