music theory online : key signatures and accidentalslesson 9
Dr. Brian Blood




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I recommend you to think when at work, not only of the musical but also of the unmusical public. You know that for ten true connoisseurs there are a hundred ignoramuses!
Do not neglect the so-called popular, which tickles long ears.
Leopold Mozart (1719-87) Austrian violinist: advice to his son Wolfgang Amadeus Mozart (1756-91)

The Key Signature :: The Circle of Fifths :: The Order of Sharps & Flats in Key Signatures
Enharmonics :: Using Accidentals :: Changing Key :: Notes and Keys in Various Languages


Important: To see and hear our 'live' music examples you will need to install the free Scorch plug-in for PC and MAC systems.


The Key Signature ::

In the previous lesson we touched upon a method for reducing the number of sharp and flat signs when writing music in a particular key. Examine the row of notes in the key of A major. C, F and G are 'sharpened'. If the notes are written with no key signature every 'sharpened' note must be marked with a 'sharp' sign. If we write the A major key signature (three sharps), at the beginning of the stave, one no longer needs to place 'sharp' signs in front of these notes. The key signature applies to all the relevant notes in every octave.

As well as simplifying the notation, the key signature tells us the key of the piece of music. The key signature appear on every line of music immediately after the clef sign. The time signature is written only on the first line, placed after the clef sign and key signature.

The bars have been numbered 'line by line'. This part is written for an oboe. On the first line the instrument name is written in full, while on the other line(s) it is abbreviated.

As an aside, it is worth remembering that the concept of key signatures as we know it today developed in the latter part of the 18th century. Music from Baroque and earlier periods may be written with key signatures containing fewer sharps or flats than we might expect. This is found particularly when the music is written in a minor key. One explanation is the association between 'key signatures' and the use of 'major' and 'minor' keys. Before the end of the 18th century, composers still thought musically in terms of modes which would, for a particular key note, tend to have different number of sharps or flats associated with them than with our modern major and minor scales. Modes may contain intervals that are not pleasing to the ear. e.g. an augmented 4th between F and B. The singers would alter these by flattening the B. Alterations such as these, were never written in the music but are an example of musica ficta which means, literally, "feigned music".

Reference

  • What is Musica Ficta? - part of an article entitled Hexachords, solmization, and musica ficta


    The Circle of Fifths ::

    We now need to determine the key signature for each of the major keys. Of course, we could work out the note row for each major key and so identify the number of sharps or flats in each key. There is, however, a shorthand way of remembering the relationship between the key and the key signature using the circle of fifths illustrated below.

    Place the note C in the twelve o'clock position on a clock face. Moving clockwise, place the fifth degree of the C major scale, the note G, in the one o'clock position. Again moving clockwise, place the fifth degree of the G major scale, the note D, in the two o'clock position. Having done this the necessary number of times you will have produced the sequence C, G, D, A, E, B, F sharp and C sharp. The key signature for each key has one sharp more than the key preceding it in the sequence. We have marked the number of sharps for the first two sharp keys

    Place the note C in the twelve o'clock position on a clock face. Moving anti-clockwise, place the fourth degree of the C major scale, the note F, in the eleven o'clock position. Again moving anti-clockwise, place the fourth degree of the F major scale, the note B flat, in the ten o'clock position. Having done this the necessary number of times you will have produced the sequence C, F, B flat, E flat, A flat, D flat , G flat and C flat. The key signature for each key has one flat more than the key preceding it in the sequence. We have marked the number of flats for the first two flat keys.

    You may be wondering why, if we use a circle of fifths, the flat keys are found by taking the fourth degree of the major scale. In fact, the fourth degree of the scale is the same note as you would get by moving a 'fifth' down the major scale.

    We illustrate below the sequence of key signatures that the circle of fifths produces in each case - moving clockwise for the sharp keys or anti-clockwise for the flat keys. The key name is confirmed by the minim appearing after each signature. The order of the sharps or flats remains unchanged in each signature and each stave in a line of music will have the same key signature adjusted for that line's particular clef.

         

    You may be wondering also why 'circle of fifths' - why not 'circle of fourths' or 'circle of thirds'. You may remember that in lesson 8 we introduced the Greek tetrachord, a row of four notes based on the interval sequence tone-tone-semitone.

    The major scale of C is just two consecutive tetrachords:

    C - tone - D - tone - E - semitone - F : the first tetrachord
    G - tone - A - tone - B - semitone - C : the second tetrachord

    Note that the first note in the first tetrachord is exactly one octave below the fourth note of the second tetrachord.

    The second scale, starting on the key note G, starts from the first note of the second tetrachord of the C major scale, that is, from the fifth degree. The two tetrachords for the G major scale are:

    G - tone - A - tone - B - semitone - C : the first tetrachord
    D - tone - E - tone - F sharp - semitone - G : the second tetrachord

    The flat keys are 'constructed' by treating the first tetrachord of the present scale as the second tetrachord of the key flatter by one accidental to it.

    The C tetrachords are:

    C - tone - D - tone - E - semitone - F : the first tetrachord
    G - tone - A - tone - B - semitone - C : the second tetrachord

    So for the major scale of F major

    C - tone - D - tone - E - semitone - F is the the second tetrachord

    and, remembering that the last note of the second tetrachord is the first note of the first,

    F - tone - G - tone - A - semitone - B flat is the first tetrachord


    The Order of Sharps & Flats in The Key Signature ::

    If you look at the sequence of steadily 'sharper' keys as one progresses clockwise around the circle of fifths, starting with G major, then D major and so on, you will find that the order of the sharps, read left to right in the key signature, preserves the order in which the sharp signs first appear; first F sharp (in G major), then C sharp (in D major), then G sharp (in A major) and so on. Again, the order of the flats, again read from left to right in the key signature, as they appear in the steadily 'flatter' keys as one moves anti-clockwise around the circle of fifths, preserves the order in which the flat signs first appear; first B flat (in F major), then E flat (in B flat major), then A flat (in E flat major) and so on.

    The advantage of a preserved order is that the last sharp or flat on the right of the key signature, itself uniquely identifies the key of the work. The performer does not need to confirm this by reading the other signs in the key signature.

    In the case of the sharp keys, the key, if it is a major key, is a semitone above the last sharp in the key signature (e.g. if the last sharp is F sharp, the key is G major); otherwise it is the relative minor, E minor.

    For flat keys, the key, if it is a major key, is the last but one flat in the key-signature (e.g. if the last but one flat is B flat, the key is B flat major); otherwise it is its relative minor, G minor.

    Obviously, in the case of one flat you just remember that this, if it is in a major key, is F major; otherwise it is its relative minor, D minor. If there is no sharp or flat in the key-signature, the key, if it is in a major key, is C major; otherwise it is the relative minor, A minor.

    For more on relative minor keys see lesson 10: Relative & Parallel Major & Minor.


    Enharmonics ::

    We have already seen that note names may not be unique; for example, D flat and C sharp. The problem is even greater than that. If you look again at the keyboard below you will appreciate that 'sharpening' and 'flattening' leads to other double named notes. For example, B is also C flat, F is also E sharp. If you refer back to the circle of fifths diagram above you will see that the five, six and seven o'clock positions each has two key names. If you play the two scales on the keyboard, the sequence of sounds will be the same for each pair of keys - the key pairs are enharmonic. Similarly with note names, E flat is enharmonic to D sharp, A sharp is enharmonic to B flat.

    C
    D
    E
    F
    G
    A
    B
    *
    C
    D
    E
    F
    G
    A
    B
    C
    D
    E
    F
    G
    A
    B

    You may be wondering why, if enharmonic keys are identical when played on a keyboard, composers don't just chose the key with the fewer sharps or flats. It is only with the modern tuning system we call 'equal temperament' that the pairs of enharmonic notes have the same pitch. In other tuning systems these two notes are actually different. C sharp, for example, is slightly flatter than D flat.

    Lesson 27 considers these matters in much greater detail.

    We set out the enharmonic notes in the table below using the (sharp), (double sharp), (flat), (double flat) or (natural) signs.

    In any column all the notes are the same pitch. In any column the notes are one semitone sharper than those in the column to the left and one semitone flatter than those in the column to the right.

    the numbers are in units of one semitone (e.g. C + 5 = C plus 5 semitones = F)
    C + 0C + 1C + 2C + 3C + 4C + 5C + 6C + 7C + 8C + 9C + 10C + 11
    B B
    C C C
    D D D D D
    E E E E E
    F F F F F
    G G G G G
    A A A A A
    B B B
    C C

    We can display the enharmonic relationships on a piano keyboard. This is shown below.


    Using Accidentals ::

    We have assumed, until now, that pieces of music are written in various keys and that, once the right key signature has been chosen, we never need to write sharp or flat signs. Actually, this could not be further from the truth. The introduction of notes from the chromatic scale that are not part of the major scale, or modulation, when the key changes, both add 'spice' to a musical line and produce a change of 'mood'.

    Generally, music starts and finishes in the same key and generally it is that key that will be indicated by the key signature. However, the key signature never 'determines' the key of a piece of music. In the sixteenth century, minor keys with key signatures made up of flats and where the sixth and seventh degrees were frequently inflected (i.e. raised by a semitone), were often written with key signatures one flat too few (i.e. without the flat for the sixth degree). As the sixth degree required a sharp or a natural, the composer would then notate this in the score. The signature was then and remains only a notational convenience that reduces the number of sharp and flat signs in the body of the score by placing them in the key signature at the beginning of the line. Notes that do not lie in the scale of the key are called accidentals and these are marked in the score by using the signs we have met already, the natural, sharp and flat signs as well as the double-sharp and double-flat signs.

    The rules for applying accidentals are simple to state today, but hundreds of years ago, the rules varied from composer to composer, from country to country and could be said to be 'confused'. Modern editions of mediaeval and renaissance music can disagree in their 'realisation' of accidentals, a situation made more difficult because the concept of key was changing from older modes to newer major and minor keys.

    So what now are the rules for using 'accidentals'?

    The sign is placed in front of the note.
    In some editions of early music, accidentals may appear above notes. In this case, the accidental is an editorial suggestion or correction

    The note-accidental combination 'names' the note to be played: so, F sharp means play F sharp, B natural means play B natural and E flat means play E flat whatever the key signature. When there is no accidental written, the actual note to be played depends on the key signature.

    The sign applies only to the line or space where it first appears; if the same note appears in another octave, or, in the case of multi-staves scores on another staff, the accidental must be restated (see the high B natural). Contrast this with the rule for signs appearing in the key signature which apply to all relevant notes in any octave on the stave.

    When used, the accidental applies only to the end of that particular bar, or until another accidental appears later in the same bar on the same note on the same line or space. The first two B's are both B naturals, the third B is marked B flat.

    There is one exception to the 'bar-line cancels the accidental' rule. If the note bearing the accidental is tied into the next bar, the accidental persists for that note only; any note after the end of the tie would have to be marked again. Both the C's in the second bar are C natural.

    Where there might be any doubt, precautionary marks (sometimes called 'courtesy accidentals') may be used - accidentals, sometimes within brackets, that confirm the status of the note. The C in the second bar would be C sharp because the previous bar-line ends the effect of the natural sign. Even so, a precautionary sharp sign has been used for the C sharp in the second bar.

    During the twentieth-century the traditional convention for applying accidentals, the convention we have described above, was extended. There are now four general approaches:
    Traditionalaccidentals apply for the duration of the bar
    Second Viennese Schoolaccidentals are used on every pitch except for repeated notes
    Modernistaccidentals apply only to the pitch to which they are attached and any immediately repeated pitches. Naturals are not used except for clarification
    Salzedoaccidentals only apply to the pitch to which they are attached, but not to any repetitions of the same pitch. Naturals are never used


    Changing Key ::

    There will be occasions when it is makes more sense to change the key signature than to rely only on accidentals. A new key signature is applied from the beginning of a bar. If the new bar-line is at the beginning of the line, a cautionary sign, may appear at the end of the previous line, after the last bar-line. We offer a trivial example to demonstrate both situations.

    The first two bars are in G major, the second two are in C major and the last four bars return to G major.

    Because the key signature for C major is normally 'empty' of sharp or flat signs, the 'change' of key is marked with a pattern of natural signs that matches the pattern of sharps or flats in the previous key signature - in this case, one natural where before there was the single sharp sign for G major.

    The application of the (sharp), (double sharp), (flat), (double flat) or (natural) sign to a note is called an inflection.
    There are two special signs used to indicate the cancellation of only one of a pair of sharps (double sharp) or flats (double flat). The two signs are and respectively.

    The table below sets out the names of the inflections in various languages.


    Notes and Keys in Various Languages ::

    English/USItalianFrenchGermanDutchDanishSwedishFinnishSpanish
    (Catalan)
    c double flatdo doppio bemolleut double-bémolCesescesescesescesescesesdo doble bemol
    (do doble bemoll)
    c flatdo bemolleut bémolCescescescescesdo bemol
    (do bemoll)
    cdoutCccccdo
    (do)
    c sharpdo diesisut dièseCisciscisciscisdo sostenido
    (do sostingut)
    c double sharpdo doppio diesisut double-dièseCisiscisiscisiscisiscisisdo doble sostenido
    (do doble diesi)
    d double flatre doppio bemolleré double-bémolDesesdesesdesesdesesdesesre doble bemol
    (re doble bemoll)
    d flatre bemolleré bémolDesdesdesdesdesre bemol
    (re bemoll)
    dreDddddre
    (re)
    d sharpre diesisré dièseDisdisdisdisdisre sostenido
    (re sostingut)
    d double sharpre doppio diesisré double-dièseDisisdisisdisisdisisdisisre doble sostenido
    (re doble diesi)
    e double flatmi doppio bemollemi double-bémolEsesesesesesesesesesmi doble bemol
    (mi doble bemoll)
    e flatmi bemollemi bémolEsesesesesmi bemol
    (mi bemoll)
    emimiEeeeemi
    (mi)
    e sharpmi diesismi dièseEiseiseis>eiseismi sostenido
    (mi sostingut)
    e double sharpmi doppio diesismi double-dièseEisiseisiseisiseisiseisismi doble sostenido
    (mi doble diesi)
    f double flatfa doppio bemollefa double-bémolFesesfesesfesesfesesfesesfa doble bemol
    (fa doble bemoll)
    f flatfa bemollefa bémolFesfesfesfesfesfa bemol
    (fa bemoll)
    ffafaFfffffa
    (fa)
    f sharpfa diesisfa dièseFisfisfisfisfisfa sostenido
    (fa sostingut )
    f double sharpfa doppio diesisfa double-dièseFisisfisisfisisfisisfisisfa doble sostenido
    (fa doble diesi)
    g double flatsol doppio bemollesol double-bémolGesesgesesgesesgesesgesessol doble bemol
    (sol doble bemoll)
    g flatsol bemollesol bémolGesgesgesgesgessol bemol
    (sol bemoll)
    gsolsolGggggsol
    (sol)
    g sharpsol diesissol dièseGisgisgisgisgissol sostenido
    (sol sostingut)
    g double sharpsol doppio diesissol double-dièseGisisgisisgisisgisisgisissol doble sostenido
    (sol doble diesi)
    a double flatla doppio bemollela double-bémolAsesasesasesasesasesla doble bemol
    (la doble bemolle)
    a flatla bemollela bémolAsasasasasla bemol
    (la bemolle)
    alalaAaaaala
    (la)
    a sharpla diesisla dièseAis aisaisaisaisla sostenido
    (la sostingut)
    a double sharpla doppio diesisla double-dièseAisisaisisaisisaisisaisisla doble sostenido
    (la doble diesi)
    b double flatsi doppio bemollesi double-bémolBesbesesbesbesbessi doble bemol
    (si doble bemoll)
    b flatsi bemollesi bémolBbesbbbsi bemol
    (si bemoll)
    bsisiHbhhhsi
    (si)
    b sharpsi diesissi dièseHisbishishishissi sostenido
    (si sostingut)
    b double sharpsi doppio diesissi double-dièseHisisbisishisishisishisissi doble sostenido
    (si doble diesi)
    sharpdiesisdièseKreuzkruiskrydskorsförteckenkorotusmerkkisostenido
    or
    elevación de un semitono
    (diesi
    or
    sostingut)
    double sharpdoppio diesisdouble dièseDoppelkreuzdubbelkruisdobbeltkrydsdubbelkorskaksoisylennysmerkkidoble sostenido
    or
    elevación de dos semitonos
    (doble diesi
    or
    elevació de dos semitons)
    flatbemollebémolB(e)molbbeförteckenalennusmerkkibemol
    or
    bajada de un semitono
    (bemolle
    or
    disminució d’un semitò)
    double flatdoppio bemolledouble bémolDoppel-B(e)dubbelmoldobbelt-bdubbelbekaksoisalennusmerkkidoble bemol
    or
    bajada de dos semitonos
    (doble bemolle)
    naturalbequadrobécarre
    or
    naturel
    Auflösungszeichen
    or
    Quadrat
    herstellingstekenopløsningstegnåterställningsteckenpalautusmerkkibecuadro
    (becaire)
    major (for keys and intervals)maggiore (for keys and intervals)majeur (for keys and intervals)Dur (for keys); gross (for intervals)
    majeurdurdurduurimayor
    (major)
    minor (for keys and intervals)minore (for keys and intervals)mineur (for keys and intervals)Moll (for keys); klein (for intervals)mineurmolmollmollimenor
    (menor)


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