How to Tell the Key of a Song
Every piece of music is written in one key or another, such as the key of Bb or the key of E or whatever. The key signature at the beginning of a score tells what sharps or flats are being used in the song, and therefore what scale the song is based on.
There is a key signature in all pieces of music. It is signified just after the clef (the staff) and includes symbols for flats (b) and sharps (#). When you take a careful look at the start of each of the lines in the music you will surely recognize a grouping of flats or sharps (never both at once). They appear either on a space or on a line of the music staff and are put there to signify the notes that will be affected by them. To say it a different way, if the #, or sharp, is placed on the top of a music staff, the F note will be played as F#. This means that anytime the note F is played, no matter if it is in the staff’s first space, on top of the staff, or below or above the staff (this will be signified by the ledger lines) it will be played as F#.
If the music requires that the note be played in a different way, not as a flat or sharp as indicated in the key signature, there will be an accidental just in front of the note to indicate it being played as a natural note. An example of this would be if the piece has been indicated to play all F notes as sharp but in one section it is needed played as a natural, the accidental will be placed just before the note that is different.
The key signature is put in place so that the sharps and flats will be limited on the actual notes in the piece of music. Basically, by putting the # in the signature key it avoids the writer from having to put a sharp or flat by each note when the F is in the music. It lets the musician know that each and every time the F note is required that it should be played as F#. The lines of music will not be as cluttered this way and it will be much easier to be read.
Here are some common key signatures and the notes they affect:
Key of C: No sharps or flats
Key of G: One sharp (F#)
Key of D: Two sharps (F# and C#)
Key of A: Three sharps (F#, C# and G#)
Key of E: Four sharps (F#, C#, G# and D#)
Key of F: One flat (Bb)
Key of Bb: Two flats (Bb and Eb)
Key of Eb: Three flats (Bb, Eb, and Ab)
There is also a relative minor assigned to each key. While it is true that in nearly all ways the major and the relative minor that coincides with it are similar (they use the same scale even though they begin in different places), they are not considered the same. The note that can be found a minor third down from the major (key) is called the relative minor. You can think of it in another way by remembering the sixth note in the major scale is the relative minor. As an example, The C major scale has a sixth note of A so an A minor is the relative minor to C. It is very common to use the relative minor of the key and if you gain a good understanding of them you will find that you have a better understanding of the chord progressions in the song.
Below are some of the keys and their relative minors (keys):
A minor is the relative minor for C.
B minor is the relative minor for D.
F# minor is the relative monitor for A.
G minor is the relative minor for Bb.
When a musician that is experienced plays in a setting that is not formal (without written music) all they need to know is what the key is to the song that they will be playing and they will immediately know the sales, or melodies, as well as the chords that are necessary to play it well.
Lastly, a song being written in more keys than one is fairly common and the key changes in the middle somewhere. The newer musicians may have difficulties when the keys change like this.
