Key Signatures & Transposition

In music notation, the key signature is at the beginning of a piece, but can also change within a piece. It indicates which notes are flats (a half-step lower), or sharps (a half-step higher) from that point forward.

In a traditional music education, you spend a lot of time practicing scales in the various key signatures, in order to instantly know which notes are flat or sharp in a given key signature's scale.

With the KeyMusician keyboard, all this can be taken care of for you, by virtue of it being an intelligent keyboard – it knows what key signature you have specified, and therefore which notes need to be flat or sharp.

All you have to do is tell it which key signature to use, and merely play the notes of the scale. The intelligent keyboard handles the black-key/white-key details. You specify the key signature using the “Transpose” button at the top-right of a performance panel.

Probably every MIDI synthesizer has a similar capability of specifying a transposition interval, and thus could take care of the key signature for you. The problem we run into with most synthesizers, is that specifying the transposition interval takes time, and where the key signature can change in the middle of a piece, you don't have time to change it.

The KeyMusician keyboard overcomes this difficulty by having you set up all of the key signatures you need for playing the piece beforehand, then you can switch to any of them simply by pressing the function-key to call up the performance panel (with the key signature you need) that you set up beforehand. So the change is almost instantaneous.

Here is a performance panel with a transposition interval of one half-step up, which yields a key signature of 5 flats:


Note that the Transpose button-face has “+1 = 5-flats” in it. This means it transposes one half-step up, and that there are 5 flats in the key signature. The flat-symbol looks like a stylized version of a lower-case “b”.

In the staff lines diagram, notice that there are five flat-symbols in each clef (for now, ignore the double-flat sign to the left of the note being played – we'll explain that later).

Like a note, the flat-symbol's roundish part indicates the staff line (or space between the staff lines) of the note that needs to be flat. However, it also implies that every other note (having the same letter-name) in whatever other octave of the clef, is also a flat.

Another thing that is important to take note of, is that the letter-names of the notes on the keyboard are always the same (a C is always just below any group of 2-black-keys). With transposition, the keyboard notes line up with different notes on the staff lines. If we play a C on the keyboard, it will line-up with a D in the staff lines, but with the key signature in-effect, it will be a D-flat, which is the note which is one half-step above the C we played.

The staff lines (in music notation) show the transposed note we are actually playing.

In the case above, if we play an F on the keyboard. It lines up with a G in the staff lines. Since the key signature indicates every G is a G-flat, that “F” we play is changed to a G-flat.

HOWEVER, in this case, I also pressed the Page-Down key, which says to make the note of the scale (in the specified key signature) a half-step lower. Since in the key signature it is already a flat, it is changed to a double-flat (whose symbol looks like two flat-symbols squashed together) to make it a half-step lower.

Since we played an “F” on the keyboard, but with the Page-Down key pressed (which makes it a half-step lower), an E-natural is marked on the keyboard diagram. This “E-natural” we play, corresponds to the “G-double-flat” indicated in the staff-lines.

A note such as this, that differs from the notes normally in the key signature, is called an 'accidental'.

Let's look at another example – this time with sharps:


In this case, the Transpose button-face contains a “-1 = 5-sharps”, which specifies transposing one half-step down, and that there are five sharps in the key-signature. Notice that the key signature in the staff lines has five sharp-signs (#) to the right of each clef symbol, indicating each clef has 5 sharps in its key signature.

As with notes, the middle part of the sharp-sign indicates the staff line (or space between the lines) of the note that needs to be sharp. Again, these same notes in every octave in the clef, are also sharps.

Notice that the C in the middle of the keyboard diagram lines up with the space below the middle-C in the staff lines, meaning it is a B. Middle C in the staff lines, is the single short line between the two clefs. So if we play a C on the keyboard, we get a B on the staff lines, which is not one of the sharp-notes. A “B natural” is precisely one half-step below the C, so it accurately shows the transposed note we are actually playing.

In the example above, I played a B on the keyboard. Because of the transposition specified, it lines up with an A in the staff lines. Since the A is one of the notes that is a sharp in the key signature, it would be an A-sharp.

HOWEVER, in this case (as with the prior example), in playing the note, I pressed the Page-Up key, which says to make it a half-step higher than the note of the key signature. So where the note of the key signature is already a sharp, it is made a double-sharp (whose symbol looks like a stylized “x”).

As with the prior case, I pressed the Page-Up key when playing the B, which raises it a half-step, which is actually a C-natural, as marked in the keyboard diagram. This resulting C corresponds to A-double-sharp in the musical staff-lines.

Let's look at one final example for this topic:


In this case, I'm showing the Chords panel, and I played a B minor 7th chord.

In the chord, the notes played are the 1st (the root-chord note), the third, (3rd note up), the fifth (5th note up), and the seventh (the 7th note up). But since the chord is a minor seventh, the 3rd and 7th intervals of the chord need to be minor intervals, which means to make each of them a half-step lower.

Where those notes are already sharps in the key signature, to make them a half-step lower, we prefix the notes in the staff diagram with a natural-sign (see the diagram above). The intelligent keyboard knows to do this for you. It is showing you an abbreviated music notation of what you are playing.

The interesting thing about how the intelligent keyboard works in this case, is that where the D-natural and A-natural were introduced by the chord played, if I played a melody note (say, in the treble-clef) which happened to be a D, or an A, it would also change it to a natural – the same as in the chord.

If a chord introduces (temporarily) a flat, sharp, or natural change from the key signature (an 'accidental'), it automatically specifies the same accidental for any melody note that is the same as any of the chord's accidental(s).

I apologize for such complicated examples, but each of them serves to illustrate useful things that the keyboard does for you. It's nice that the software takes care of this complexity for you, and you don't need to delve into it.

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