Key-Signatures – The Why, How, and Wherefore

If you've looked at sheet-music, you've undoubtedly seen a variety of key-signatures. In music, the key-signature is shown at be beginning of the piece, and at the left side of every line of music. It appears as a number of sharp-signs (#), or flat-signs (like a stylized 'b'). But doesn't only appear at the beginning of a piece. It can change within the piece.

The key-signature is actually musical short-hand telling the musician which notes should be played as flats, or as sharps.

Here is an example of a key-signature, having three flats:

The above key-signature tells us that every B, E, or A note should be played instead as B-flat, E-flat, or A-flat.

This key-signature could also be referred-to as the key of E-flat major, or the key of C-minor.

Usually, you specify the key-signature as the number of flats or sharps. That's the easiest – just count how many flats (or sharps) in any individual staff-line of music.

But a singer might say something like, “That music is too high for me to sing. Can you please transpose it down a few notes?” In this case, you smile, and say “Sure – no problem. How many notes (2 half-steps per note) do you want it transposed down?”. After they tell you how many notes to transpose it, you could click on the “Transpose” button, and use the “Semi-Tones Up/Down” drop-box to transpose it down (a semi-tone is a half-step).

Or you might want to improvise music along with someone playing the famous Palchelbel “Canon In D”. If a key-signature name is just the letter-name of its root-note, it means major, so that means D-Major. You would use the “Major Key-Name” drop-box to specify “D Major”.

The positive (+) or negative (-) number that appears with it, tells you the number of half-steps it is transposed from C, which is sometimes useful to know. Think of the key of “C” as 0 degrees on a thermometer, and the negative or positive number like the number of degrees above, or below 0.

Or you might want to play-along with the first movement of Beethoven's 5th Symphony, playing on a CD. Since you remember (or see on the album cover), that its key is C-Minor, you use the “Minor Key-Name” drop-box, and select “C Minor”.

Very often, pieces of music are entirely in just one key-signature, so to play such pieces, all you have to do is set the performance pane(s) you plan to use, to that key-signature before playing the piece, then start playing.

But a piece of music can (and often will) change key-signatures right in the middle of the piece (in the middle of a set of staff-lines of music), with no pause before the change. In such cases, you obviously don't have time to set the key-signature as explained above.

In such cases, before playing the piece, you set up a separate performance pane for each key-signature used, and switch between key-signatures by simply hitting the function-key associated with the key-signature you set up for it beforehand.

If you're playing several such pieces, you can set it up beforehand, and save a separate configuration (.kmk) file for each such piece, possibly named for the individual piece, or perhaps named for the particular performance, with a sequence number (1, 2, 3, …) of the order you play them in the performance.

Here is a key-signature you might see in sheet-music, followed by the “Set Transpose Interval / Key-Signature” dialog box settings to specify that key-signature.

If you learn to play a traditional music keyboard, you have to spend a lot of time playing scales in all the different key-signatures, so that you learn instinctively with each key-signature, which notes are black-keys (as opposed to white-keys).

With the KeyMusician Keyboard, there is no such need, because you simply specify the key-signature, and the fingering is the same.

Why do they use different key-signatures?

We mentioned above the case where a piece of music might not fit the range of notes a singer is able to sing reliably. But there are other reasons too.

A big reason a composer chooses one key-signature over another, is that the same piece of music actually sounds different when played in different key-signatures. This difference is subtle, but it is significant.

From my own experience as a composer, I came up with music I liked on the piano (or synthesizer), and that music usually used some black-keys. It was only when I came to the point of writing the music down that I needed to figure out which key-signature it was in.

Musicians sometimes talk about different key-signatures making them think of different colors. Also, some key-signatures (such as D-major) may seem “bright”.

To convince yourself of this difference, try playing a tune (say, for example, “Ode To Joy” in the KMK Songbook) usually played in a key other than D, in the key of D (2 sharps), but using the same keyboard keys you used when you played it before. Besides being pitched higher or lower, it actually has a different sound.

But why would it have a different sound? It's just a sequence of musical notes.

The reason is the way keyboard instruments are tuned.

It may surprise you, but keyboard instruments cannot be tuned so that every interval is perfectly in-tune. This is because it needs to be able to play different key-signatures.

A piano is tuned so that each interval is a 'little-bit flat' or a 'little-bit sharp', according to a certain formula. This is called “Tempered” tuning, and it results in the instrument being able to play all key-signatures with a good (but not perfectly in-tune) sound.

This “Tempered” tuning is why the same piece, played in a different key-signature, sounds different.

The configuration files supplied with the KeyMusician Keyboard are pre-set to use the key of C-major (or A-minor), which has no flats or sharps. In making up my own music, should I be playing in other key-signatures?


If you don't play in other key-signatures, the music you compose or improvise will all sound much the same. You really do need to try playing in different key-signatures. You may very well find that your favorite key-signature is not the one supplied by-default.

Certainly, you could just change the key-signature in each performance-pane (other than the Drums pane), but to make it easy, I have supplied a configuration-file (with all the performance-panes set) for all of the key-signatures.

These configuration files are based on the FluidR3_GM.kmk configuration file, but include the Cello (in the F9 pane), and the Bassoon (in the F12 pane). These instruments are particularly good using the FluidR3_GM soundfont, but not so good in other soundfonts.

You can easily download the files and use them. You need to put them in the “KeyMusician-Keyboard” folder (before starting the KeyMusician Keyboard) for them to be visible in the “Configuration File” drop-box.

To download them, right-click on each of the links below, and choose “Save Link As” (or something similar) from the pop-up menu.

Key-0b.kmk (no flats or sharps, C-major or A-minor)

Key-1b.kmk (1 flat, +5=F-major or D-minor)

Key-2b.kmk (2 flats -2=B-flat-major or G-minor)

Key-3b.kmk (1 flats +3=E-flat-major or C-minor)

Key-4b.kmk (1 flats -4=A-flat-major or F-minor)

Key-5b.kmk (1 flats +1=D-flat-major or B-flat-minor)

Key-1#.kmk (1 sharp -5=G-major or E-minor)

Key-2#.kmk (2 sharps +2=D-major or B-minor)

Key-3#.kmk (3 sharps -3=A-major or F-sharp-minor)

Key-4#.kmk (4 sharps +4=E-major or C-charp-minor)

Key-5#.kmk (5 sharps -1=B-major or G-sharp-minor)

Alternatively, you could right-click on the following zipped-archive link, save it in the KeyMusician-Keyboard folder, and expand it there, giving you all of the above key-signature files: (all of the above, as a zipped-archive)

Give them a try, improvising music in all of the key-signatures.

When using the “Transpose” button, you may notice that there is more than one choice for some key-signatures. In the files above, I have chosen the alternative that requires the smallest number of half-steps of transposition.

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