3 Flats: E Flat Major / C Minor
Three flats is E flat major, or C minor. The flats are B flat, E flat and A flat, and the second-to-last of them — E flat — names the key.
3 flats
E♭ major / C minor
With flats, the second-to-last flat names the major key directly: the flats run B♭, E♭, A♭, so the key is E♭ major.
E♭ major scale
E♭ F G A♭ B♭ C D
C minor scale (relative minor)
C D E♭ F G A♭ B♭
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E♭ major scale
E♭ F G A♭ B♭ C D
C minor scale
C D E♭ F G A♭ B♭
The E flat instruments
Where two flats is the B flat instruments' home, three flats belongs to the E flat family: the alto saxophone, the baritone saxophone, the E flat clarinet and, historically, a large part of the brass band. Those instruments sound a concert E flat when they read a written C.
The practical consequence in a mixed ensemble is that no single concert key is easy for everyone. Concert E flat gives the alto and baritone saxophones a plain C major part and the B flat instruments an F major part with one flat — both very manageable. It is one of the reasons E flat, B flat and F form the working core of wind writing: they are the keys in which the transposition arithmetic works out kindly for the largest number of players at once.
The heroic key
E flat major carries an unusually strong set of associations in the classical repertoire, and they are attached to specific and well-documented works rather than to vague tradition. Beethoven's Third Symphony, the Eroica, is in E flat, as is his Fifth Piano Concerto and much of the writing for natural horn that shaped the key's character in the first place.
That last point is the mechanical origin of the association. Before valves, a horn could only play the notes of the harmonic series of whichever crook it was fitted with, and E flat was one of the standard crooks. Composers wanting a full, ringing horn sound wrote in the keys the instrument could actually play, and the resulting sound became the association. The reputation followed the hardware.
C minor
The relative minor is C minor — and it has as strong a reputation as its relative major, in the opposite direction. Beethoven's Fifth Symphony and his Pathétique sonata are both in C minor, and both are freely available as public-domain scores.
On instruments it behaves much like B flat major does: comfortable for winds, a third-fret barre on guitar, and unremarkable on a piano. Its raised seventh degree for cadences is B natural, which means a piece in C minor is full of B naturals contradicting the B flat in the signature. That pattern — an accidental repeatedly cancelling one of the signature's own flats — is the standard signature of a minor key in written music.
The scale and its chords
E flat major is E flat, F, G, A flat, B flat, C, D. Three notes are lowered; four are natural. It is the last flat signature where the naturals still outnumber the flats, which makes it a reasonable outer limit for a reader who is not yet fluent in flat keys.
The diatonic chords are E flat, F minor, G minor, A flat, B flat, C minor and D diminished. Of those, B flat major as the fifth degree is the cadence chord, and G minor and C minor both appear — which is to say the two keys of the adjacent signatures both live inside this one, a relationship the circle of fifths makes visible at a glance.
The seven chords of E♭ major
Every major key produces the same pattern of chord qualities — major on the first, fourth and fifth degrees, minor on the second, third and sixth, diminished on the seventh. Only the names change.
Questions people ask about this signature
- Three flats is what key?
- E flat major, or C minor. The three flats are B flat, E flat and A flat.
- Why do saxophone players see this key so often?
- Because alto and baritone saxophones are pitched in E flat and sound a concert E flat when they read a written C. Music written in concert E flat gives them the simplest possible part.
- Why does music in C minor keep showing B naturals?
- Because minor keys raise their seventh degree at cadences. In C minor the seventh degree is B flat in the signature, so raising it produces a B natural written as an accidental in the music.