Key Signatures

Introduction 

  • A key is the pitch collection of notes in a composition and the hierarchal relationship between them 

  • Key signatures indicate which pitches should always be played with accidentals 

  • Sharps and flats do not appear together in the same key signature 

Function of the Signature 

  • Any accidental in key signature applies to all notes it refers to, regardless of octave 

  • Key signature is always placed after clef and before time signature 

Sharp Keys 

  • Order of sharps: F C G D A E B 

  • Seven Sharp minor keys 

    • C major: 0 sharps 

    • G major: 1 sharp 

    • D major: 2 sharps 

    • A major: 3 Sharps 

    • E major: 4 Sharps 

    • B major: 5 sharps 

    • F-sharp major: 6 sharps 

    • C-sharp major: 7 sharps 

  • In a major key signature, the last sharp is always the leading tone in the key 

  • The tonic and the name of the key is always a half step above the last sharp in the key signature 

    Building a sharp major key signature ( A Major Example) 

  1. Find the sharp that is a half step below A: G# 

  2. Add all the sharps to that point: F#, C#, G# 

Flat Keys 

  • Order of Flats: B E A D G C F 

  • You cannot reorder the flats in a key signature or start on any other flat except Bb 

  • Seven Major Flat Keys: 

    • C Major: 0 flats 

    • F Major: 1 Flat 

    • B flat major: 2 flats 

    • E flat major: 3 flats 

    • A-flat major: 4 flats

    • D-flat major: 5 flats 

    • G-flat major: 6 Flats 

    • C-flat major: 7 Flats 

  • In a flat key signature, the next-to-last flat is the name of the key- The Tonic 

Building Flat Key signatures (E-flat Example) 

  1. Find E in the order of flats. Add the flats up to that point. Bb and Eb 

  2. Add one more flat (in the order of flats): Ab 

  3. Build the key signature following the correct order and placement of flats