Center
C major / A minor: no sharps and no flats.
Basic Music Theory
The theory ideas most relevant to reading SingLet scales and enharmonic spellings.
Circle of Fifths
The circle of fifths is the quickest map for understanding how keys relate to one another. It shows why some practice pages sit on a sharp side, others on a flat side, and how spelling stays distinct even when outer keys draw close in sound.
- Clockwise movement adds sharps.
- Anticlockwise movement adds flats.
- The outer ring shows major keys.
- The inner ring shows relative minor keys.
Key Signatures
A key signature tells you which sharps or flats belong naturally to a key. That is why C major and A minor sit at the center with no sharps or flats, while other keys spread outward into sharp-side and flat-side groupings. Standard key signatures are usually kept within the practical set that avoids double accidentals, which is why the common circle-of-fifths view centers on the familiar major and minor keys rather than pushing further into more cumbersome spellings.
The table below unfolds the circle into flat and sharp sides so the key signatures can be read directly. C major and A minor provide the no-accidental center, and the outer rows show how added accidentals and spelling choices shape each key.
Sharp-side group
G, D, A, E, B, and F# major add sharps step by step, alongside their relative minors.
Flat-side group
F, Bb, Eb, Ab, Db, and Gb major add flats step by step, alongside their relative minors.
Enharmonic edge
Keys like C#/Db or B/Cb show the edge of the usual system, where notation tries to avoid moving into double-accidental territory.
Relative Major and Minor
Each major key has a relative minor that shares the same key signature, even though the tonic changes.
C major / A minor
Both use no sharps and no flats, but they center on different tonics.
G major / E minor
Both use one sharp, so they share a signature while sounding like different tonal homes.
F major / D minor
Both use one flat, showing the same pattern on the flat side of the circle.
Enharmonic Equivalents
Some differently spelled notes or keys can sound the same on a modern instrument, but they still carry different notation, harmonic role, and spelling identity. In ordinary teaching materials, notation usually stays within spellings that avoid double accidentals whenever possible, which keeps key signatures and scale reading manageable.
F# and Gb
They may sound the same, but they belong to different notational contexts. SingLet keeps that spelling difference visible instead of treating the two spellings as interchangeable labels.
C# and Db
The pitch can match, while the spelling still points to a different key or scale role. The distinction matters when the notation is meant to show how the music is built.
B and Cb
These spellings can approach the same sounding pitch in equal temperament, yet the notation still says something different about the key, function, and reading path.
Why Spelling Matters in SingLet
SingLet is useful here because it keeps written spelling distinctions audible and singable instead of collapsing them into one generic sound label. That matters when notation, harmonic role, and enharmonic context all need to stay visible to the learner.
Where to Go Next
This page is orientation. Next comes How It Works, where SingLet's design responds to this musical landscape, followed by scale comparisons and early pilot audio/video recordings.
Major Scales
See the major-key theory pages organized by the same circle-of-fifths logic.
Open Major ScalesMinor Scales
Compare natural, harmonic, and melodic minor spellings in one place.
Open Minor ScalesPilot/Demos
Hear short demos and fuller song examples after reading the theory background.
Open Pilot/Demos