Let’s take a look at the flat sign. When typing, we normally use the regular lowercase letter, “b” to represent this sign, but the actual symbol is ♭ which is is a stylized lowercase “b”.
In terms of its effect on a note, this sign is basically the opposite of a sharp sign. When you come across a sharp before a note on a musical piece, it means to play the note one half step (semitone) higher. When you come across a flat sign, you are to play the note that is a semitone lower. For instance B♭ is a semitone lower than B. B♭ is the black key to the immediate left of B on your piano. E♭ is one semitone (half step) lower than E and is the key to the immediate left of E on your piano. A♭ is one semitone lower than A, and so on. Anytime you see a flat symbol before any note on a piece, go one piano key to the left.
The black keys on your piano can be either sharp or flat. It depends on the key signature of the music and the choice of the composer. Each black key is usually represented by two note names, but in theory, they can have other names (as we shall talk about later).
Examples of keys having two names: The key to the right of C can be called C#, but since it is to the left of D, it can be called Db as well. The key to the right of D can be called D# but since it is to the left of E it can be called E flat as well. In other words, one half step higher makes a key sharp, while a half step lower makes it flat.
Enharmonics are notes that are the same pitch but are known by at least two different names. C sharp and D flat are enharmonics of each other. The same can be said of D sharp and E flat, G sharp and A flat, F sharp and G flat, and A sharp and B flat.
The white keys are called natural keys.
In terms of natural keys and flats, the 12 keys on your piano in order, starting on C natural are C, D♭, D, E♭, E, F, G♭, G, A♭, A, B♭ and B.
Here’s a diagram showing natural and flat keys on piano.
Having said all of this, allow me to sound a note of caution. Notes and keys are not the same. Beginners are usually of the view that flats and sharps are only played on black keys. This is not so. A flat sign means to play the key that is a half step lower, therefore if you come across an F note on a piece of music, it means to play the note that is a half step lower. That note is F flat and it is the enharmonic of E on piano, a white key. If you see a C flat, it means to play one half step lower than C which is a white key on your piano, the enharmonic of B.Learn why notes and keys are not the same here.
When you come across a flat note on a musical piece, you are to assume that the note will stay flat for the rest of that measure. It is not necessary for a flat sign to be placed before that note again until the measure ends. When the measure ends, the flat is no longer in effect. The same applies to the other type of accidentals, known as sharps. To cancel out an accidental (sharp or flat), a natural sign is used.
Sometimes, the flat note is placed in the key signature. For example, the key of F major has one flat, Bb. The pitches for the F major scale are F-G-A-Bb-C-D-E. Every time you come across B, you are supposed to play Bb. Every B is flatted in the key of F, unless it’s canceled out by a natural sign. Thanks to key signatures which indicate which notes have to be flatted or sharpened, you don’t have to keep using accidentals throughout a piece of written music. This makes everything cleaner and simpler.
How does one draw a flat sign?
A flat musical sign consists of a small loop and a stem. It is placed in front the note. The loop is placed directly on the line or space of the notehead to which it belongs. If the flat effects a pitch that is on a space, the loop should be in the middle of that space. If the notehead is on a line, the line should run through the middle of the loop of the flat sign. The stem of the flat sign is about two and a half staff spaces in length.
Double Flat Sign
Another musical symbol is the double-flat. Double flats lower a note by two half steps (a whole step). For example, a double flat symbol before E means to play the key that is two semitones lower on your piano; that key is D. This symbol consists of two flat signs next to each other, touching each other. The double-flat symbol is not as common.
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