How to Determine Major Key Signatures in Music
- 0:53 What Is 'Key'?
- 2:13 Key of C Major
- 2:33 Order of Sharps
- 4:10 How to Determine Sharp Key Signature
- 5:10 Order of Flats
- 6:27 How to Determine Flat Key Signature
What is a key signature? How can you tell the key of a song by just looking at it? Are there flats and sharps in all songs? What are some common key signatures in the Major tonality? Find out in this lesson!
How to Determine Key Signature in Music
The cards have all been dealt, and the chips are 'all-in.' You check your cards one last time to ensure your win - the ace, the king, the queen, the jack and the wild-card deuce…or wait, was that the wild-card seven? Or was it the joker? Don't you wish you had a key to remind you?
This is exactly what key signature does for musicians. It shows what sharps or flats are used in a piece of music. The key signature is always shown at the beginning of a piece of music and comes just after the clef sign. The key signature varies from piece to piece and instrument to instrument, so it's always important for the player to check the key signature before playing.
What is 'Key?'
The key signature also clues the musician in to which key they are playing. But what does that mean, exactly? Key is the scale on which a piece of music is centered. Within this, there is usually one 'home' note that the key centers on. This note is called the tonic, or the tonal center, and is most often the first note of the scale used in the piece.
If you were singing the scale - do, re, mi - and so on, the tonic would be 'do.' So when you see a piece of music where the title indicates D Major, you can assume that the key is D Major, the tonic is D and the notes of the song will revolve around tension and release of the note D.
You can think of key like a solar system. The planets rely on the sun for gravitational pull, which is essentially how notes of a song rely on a key or tonal center. Most composers use a tonal center to make their piece understandable and to make the piece come together as a whole. Those that don't use tonal centers in their compositions tend to have music that sounds a little 'lost in space.'
The Key of C Major
The easiest example of key and key signature is C Major. C Major is every musician's favorite key because it has no sharps or flats. So the notes used are C, D, E, F, G, A, B, C - and C is the tonic because it is the note that everything is centered around.
Order of Sharps
But how can one determine the key of a song if it's not C Major, and it isn't listed in the title? Through some examination of the key signature and a few tricks, you can easily find the key of most songs. Let's start with the sharps. The sharps written in a key signature are always written in a particular order called the order of sharps. The order of sharps is F#, C#, G#, D#, A#, E# and B#. This is a strange order to remember, but there are two tricks you can use. If you're a words kind of person, you can use a mnemonic device, like 'Fat Cows Get Dizzy After Excessive Breakdancing.'
If you're a numbers kind of person, you can simply count. When written alphabetically, each letter note listed in the order of sharps is exactly five letters away from the next sharp. So if we number these sharps, starting with F# as 1, G# as 2, A# as 3, B# as 4 and C# as 5, we can see that the fifth note away from F# is C#. If we need another sharp, we can call C# 1, and counting through, we can see the fifth sharp would be G#. We can continue this all the way through the order, making sure that the letters are always a fifth apart, and we would arrive again at the order of sharps: F#, C#, G#, D#, A#, E# and B#.
How to Determine Sharp Key Signature
Now that you know the order of sharps, you can use it to determine the key of a song. Let's start with one sharp. Sharp key signatures with Major tonality are super-easy to figure out because the key is always one half-step higher than the last sharp shown in the key signature. So here, where we have F#, we know that the next half-step is G. This tells us that the key signature with one sharp is G Major.
Let's try two sharps. The order of sharps tells us that the first two sharps are F# and C#. Since C# is the last sharp shown in the key signature, we go a half-step higher than C#, and we find that this is the key signature for D Major. Try one on your own. Since the last sharp is D#, we know that this key is the key signature for E Major.
Order of Flats
So you know how to find the sharp keys now, but what about the flat keys? Like the order of sharps, the order of flats are always written in a particular order on the staff. Fortunately, they are written in the exact reverse order of the sharps, so if you know one, you know the other. So the order of flats is: Bb, Eb, Ab, Db, Gb, Cb and Fb. If you really want to, you can make a new mnemonic, like 'Birds Eating All Day Get Chunky Flab,' or you can count through the flats in a similar way that you did with the sharps.
It's important to note that the flats are a fourth apart, meaning they are only four letters apart instead of five like the sharps. So when written alphabetically, Bb is 1, Cb is 2 and so on. We can see that the fourth note away from Bb is Eb. A fourth away from Eb would be Ab, a fourth from Ab is Db, and if we continue throughout the flats, we'll arrive again at the order of flats: Bb, Eb, Ab, Db, Gb, Cb, Fb.
How to Determine Flat Key Signature
The keys of Major flat key signatures are head-slappingly easy to find. All you have to do is find the second-to-last flat in the key signature, and that's the key. So in this case, where we have Bb and Eb, the second-to-last flat is Bb, and therefore the key is Bb Major. Here, we have four flats, and since the second-to-last flat is Ab, we know that this is the key signature for Ab Major. Try this one. The second-to-last flat shows us that this is the key signature for Eb Major. There is one case where this strategy won't work, so just remember that when there is only one flat, the key is F Major.
You just learned a whole lot about keys and key signatures. Key is the scale on which a piece of music is centered. The tonic or tonal center is the one 'home' note where the key centers on. The key signature shows what sharps or flats are used and is always shown at the beginning of a piece of music. The order of sharps is F#, C#, G#, D#, A#, E# and B#, and the order of flats is the reverse: Bb, Eb, Ab, Db, Gb, Cb, Fb. Sharp key signatures can be determined by going one half-step higher than the last sharp, and for flat key signatures, you can find the second-to-last flat.
Chapters in Music 101: Intro to Music
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