Flat key signatures indicate which notes should be played a half step lower throughout a piece of music. The symbol for a flat is ♭. According to musical notation, flats are notes that are lowered in a given key signature. This means that any note marked with a flat symbol should be played a half-step lower than its natural position on the musical staff. For example, a B♭ is a half step lower than a B.
Understanding Flat Key Signatures
Flat key signatures are used to create minor keys and those that have a specific sound or mood. These signatures are located at the beginning of each staff and indicate notes that will be consistently flatted throughout the piece of music. The order in which flats are added to a key signature follows the circle of fifths in reverse and the order of flats is always the same: B♭, E♭, A♭, D♭, G♭, C♭, and F♭.
How to determine the key from a flat key signature
- Look at the Second-to-Last Flat: The name of the key in a flat key signature is always the second to last flat in the signature.
- Example: If a key signature has B♭, E♭, and A♭, the second to last flat is E♭, thus, the major key is E♭ Major.
- Relative Minor: The relative minor of a major key is found three half steps down from the root note of the major key.
- Example: The relative minor of E♭ Major is C minor.
Flat Key Signatures Examples:
| Number of Flats | Flats in Key Signature | Major Key | Relative Minor Key |
|---|---|---|---|
| 1 | B♭ | F Major | D Minor |
| 2 | B♭, E♭ | B♭ Major | G Minor |
| 3 | B♭, E♭, A♭ | E♭ Major | C Minor |
| 4 | B♭, E♭, A♭, D♭ | A♭ Major | F Minor |
| 5 | B♭, E♭, A♭, D♭, G♭ | D♭ Major | B♭ Minor |
| 6 | B♭, E♭, A♭, D♭, G♭, C♭ | G♭ Major | E♭ Minor |
| 7 | B♭, E♭, A♭, D♭, G♭, C♭, F♭ | C♭ Major | A♭ Minor |
Practical implications
- Consistency: Once a flat is placed within a key signature, every instance of that note (for example, B in a B flat key) on the staff is automatically lowered.
- Readability: Key signatures help make musical scores easier to read because a flat symbol isn't required before every affected note.
- Transposition: Understanding flat key signatures allows musicians to transpose music easily from one key to another.
The first flat key signature is the key of F major, or its relative minor, which is D minor (Dm).
