Modulation
Modulation can be defined as the changing of key within a song (or chord progression). It is very important to recognize a modulation, should it occur, and adjust the fret location of each pattern accordingly.
In sheet music, a modulation is sometimes indicated by changing the key signature. This will usually be done if the modulation occurs between one section of the song and the next (e.g., between one verse and another). Where there is no change of key signature, a modulation may be detected by examining the melody and/or the chords. When examining the melody, remember that each key is recognizable by the notes of its scale. If different notes appear it may indicate a modulation. E.g., if a melody in the key of C suddenly features F# notes, it could suggest a modulation to the key of G. When examining the chords, a modulation may be determined by following the chord/key relationship, i.e., looking for chords that "fit in" to a certain key. Consider the following progression:
which can be analyzed as such:
The use of Roman numerals makes the lay-out of this progression very clear, it is based on the IIm7 - V7 chords, modulating through four different keys. This type of modulation is most common in Jazz songs. You will find that many Rock songs, although featuring modulation, will not do so to such a great extent.
One of the most common modulations in songs is from the major key to its relative minor:
No change of pattern is necessary in this situation, however, different notes should be emphasized, i.e., when modulating to the relative minor key (A minor), the new root note (A) should be emphasized.
Another common form of modulation is to change up to the key one semitone or one tone higher. This can be done successively, as in the following example:
When a modulation occurs, your patterns will change fret accordingly. For example, if a major key chord progression modulates through the following keys: C – G – F – C then the fret location of pattern one will change as such:
However, it is not necessary to change positions; instead you can change patterns to avoid uncomfortable "jumps" up and down the neck. E.g., consider the use of three patterns:
Hence you are able to change key with minimal position changes.
