Shifting territory
(Changing key)
A huge variety of games can be played by moving chords around without the key window moving. But when the key window (the white area) is allowed to move as well, this multiplies the range of games that can be played.
It is worth noticing one very interesting result of moving the key window one step along the diagonal (dominant) axis.
The red circle around the C shows that the key of C is intended here. The position of the red circle in the middle of the “west coast” of the white area shows that the key is C major. Consequently ll of the notes in the white area are in the key of C major.
This feature of the diatonic scale is rare among the world’s scales, and is one of the reason why the diatonic scale has such powerful resources.
A related move is to slide the key window downwards on the dominant axis. This is called a move to the subdominant key.
The starting point again is the key of C major.
The starting point again is the key of C major.
The entire white area has shifted upwards diagonally. The notes F and A at the bottom of the key window got lost by the move. But the notes F# and A were captured at the top! So the net result is that just one note in the scale shifted up a semitone! However, see how the home note of the scale has moved up 7 semitones on the bass-players favourite dominant axis! Notice also that the new home note now occupies the position used in the previous key signal imminent return home. This means that with a tiny inflection the melody an important change in harmonic home can occur.
This move is called a modulation to the dominant key
This time the white area has shifted downwards diagonally. The notes B and D at the top of the key window get lost by the move, but the notes Bb and D are captured at the Bottom! So again just one note in the scale shifts by a semitone! While the centre of the key shifts by 7 semitones. This move is called a modulation to the subdominant key, or many purposes, the dominant and subdominant are the closest keys to any starting key.
An interesting detail is that modulating (changing key) to the subdominant has cased some of the notes to be written (“spelled”) differently - for example F# is now “spelled” Eb even though it is exactly the same note. For our purposes this is not at all important, but in some circumstance trained musicians consider it important, so Harmony Space tries to accommodate this automatically.
However, under the preference menu, Harmony Space has options “spell sharper” and “spell flatter”, so it is usually possible to arrange the note spelling to accommodate personal preferences.
To get an idea of the range of games you can play by changing key, two interesting pieces to look at are John Coltrane’s Giant Steps and the Jazz standard “All the Things you are”.
Other important related keys
One common way to change a mood is to shift the home emphasis from the major centre to the minor or vice versa. This does not involve moving the key window or cleaning any new territory, just shifting the emphasis of where home is taken to be. This is called changing from the relative major to the relative minor, or vice versa.
An interesting variant of this is a change from a major key to a minor key, where the home note does not change, but the white area does move underneath it, so that the location within the key window alters. This is called modulation to the parallel major or parallel minor as appropriate.
While the notes, including C, never move, the white area has moved so that whereas previous C was in the centre of the west coast of the white area, indication the key of C major, now it is in the “centre” of the “east coast”, indicating the key of C minor.
Harmony space has controls to make changing keys and modes in various specialised ways easier.
If relative operation is selected in the mode window, you can switch to any relative mode just by clicking on the mode name.
If parallel operation is selected in the mode window, you can switch to any parallel mode just by clicking on the note name in the key change pane.
To change key without changing mode click on the key name (e.g. C, G etc) in the key change pane.
To change key to an arbitrary key and mode (e.g. F dorian) with parallel operation selected in the mode window, click on the desired key name (e.g. C, G etc) in the key change pane, then the mode.
OR
To change key to an arbitrary key and mode (e.g. F dorian) with relative operation selected in the mode window, click on the desired mode first and then the key name (e.g. C, G etc) in the key change pane.
When step recording songs, it is neater to use the parallel modulation menu for parallel modulations.