Key Signatures and the Circle of 5ths

A free video tutorial from Victoria Williams LmusTCL BA(Mus)
Music Theory Specialist - Founder of My Music Theory
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Key Signatures and the Circle of 5ths

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Music Theory ABRSM Grade 5

Updated for 2018! Learn how to Pass the ABRSM Grade 5 Music Theory Exam and enjoy the process!

05:17:33 of on-demand video • Updated August 2020

Pass the ABRSM Grade 5 Music Theory Exam
Understand music notation in four clefs (treble, bass, alto and tenor)
Know the major and minor scales in 26 keys
Be able to work out intervals and transpose into a different key
Understand chords, inversions and basic harmony
Gain a thorough understanding of the fundamentals of music theory
Key signatures are special groups of sharps or flats which are written at the beginning of the stave, immediately after the clef. The clef and key signature need to be written on every stave in a piece of music, not just at the beginning. For your exam you'll need to be able to name the two keys one major and one minor, shown by each keysignature. And you also need to be able to write out the key signatures correctly. This means not only putting the right sharps or flats on the stave, but also putting them in the right order, and in the right positions on the stave. We'll start by learning the key signatures for the major keys. And to do this we can use a tool called the Circle of Fifths. Start by drawing a circle and divide it up into 12 like a clock. It doesn't have to be exact. At 12 o'clock write, "C" for C major. Now moving around the clock in a clockwise direction, the next key is G major. G is a perfect fifth higher than C, or 7 semitones (half steps) higher. Each step on the circle as you go round, will be a perfect fifth/7 semitones higher than the last one. On this side of the circle we will only be using white notes (notes without any accidentals). After G comes D, then A, then E, then B. At six o'clock we need F sharp. On the left hand side of the circle we're going to add the keys which are a perfect fifth lower than each other. Starting from C and counting down seven semitones, we come to F. Now, we could carry on working out the notes a fifth lower for each step, to complete the rest of the circle. But there is a quicker way. In fact, the rest of the left side of the circle uses the same letters as the right hand side, but in reverse order, and with a flat symbol added to each. At the six o'clock position we have F sharp. Reading the notes backwards from there, you should be able to see that they spell out the word BEAD. So we're going to write the word BEAD downwards on the left hand side, and add flats to each key. Now there's only one last key to add, at the six o'clock position: We need to add in G flat as well as F sharp. This is the only part of the circle that overlaps. G flat is a fifth lower than D flat, and it's also the same note as F sharp, just spelled a different way or an "enharmonic equivalent". This also happens to be the note which is furthest away from C on the piano keyboard, whether you count up or down from C. And it's also the furthest note from C in the circle of fifths. Now that the circle is complete, you need to add numbers around the outside. Start with 0 above the C, then add the numbers 1 to 6 down each side. These numbers tell you how many sharps and flats there are in each key signature. Sharp keys are on the right and flat keys are on the left. You can see at a glance that D major has two sharps, or that D flat major has five flats, or that F sharp major has six sharps. But of course, we also need to know which sharps or flats are in each key signature, not just how many there are. Luckily, the circle of fifths can tell us this as well. Let's start with G major. It's got one sharp which is F#. D Major has two sharps:F# shop and C#. Look closely at the circle, and see if you can find the letters C and F together. A major has three sharps: F#, C# and G#. E Major has F#, C#, G# and D#. The order of sharps also follows the circle of fifths. Can you work out the sharps and their order for F sharp major? They are F#, C#, G#, D#, A# and E#. On to the flat key signatures: F Major has one flat and it is Bb. B flat major has two flats, Bb then Eb. E flat has three flats, Bb, Eb and Ab. Can you see which flats A flat major has? Bb, Eb, Ab and Db. The order of flats is also right here, in the circle of fifths. What about G flat major, which flats are in that key? Bb, Eb, Ab, Db, and Gb makes five flats, but what is the sixth one? Although we've run out of flats on this part of the circle, you can see from the top part of the circle that C follows G, and it's also true that Cb follows Gb. So in G flat major, the sixth flat is Cb. The circle of fifths is so useful that I'd really recommend that you practice writing it out several times, before you take your exam. On exam day you could sketch out a circle of fifths in pencil, and use it for reference. In this section of the Course I've included a PDF template of the circle so that you can practice writing it out.