In music, modulation is most commonly the act or process of changing from one key (tonic, or tonal center) to another. This may or may not be accompanied by a change in key signature.
Typically if the original tonal center is changed for 15 seconds or more, we can define it as a modulation. On the other hand if there is a temporary change in tone center only, we will use note alterations and the change will not be considered as a modulation in the music piece. Practically speaking, if we can still “feel” the original key center during and after a change in tone, this change should be considered accidental.
A lot of musicians struggle with the question “… how do I develop a chordal sequence so I can get from one key to a different one“, being the goal for the transition to be as smooth as possible.
There are lots of modulation theories available, as being used for different music styles: classical music, Jazz, Contemporary; however we will focus on few common methods which are acceptable and can be applied to most music genres. The chord structures might change based on music styles but these modulation concepts can still be followed.
Let’s start off by defining a default modulation technique. This would consist on just applying a diatonic chord of the target key center right off the original key center chordal sequence. This will obviously sound very harsh and unnatural, so I will be presenting some other options to create a modulation sequence of chords in order to complete the transition between original key center and the target one.
Method #1: Precede the target chord with its dominant 7 chord. The idea behind this is that the resolution from the diatonic dominant chord to its key center chord is very strong. This method is slightly better than just a sharp transition to the target, however it is not as smooth as the next methods, since an abrupt tonal change will be heard between the original chord sequence and the target chord dominant7.
Method #2: Diminished- Dominant Motion to Target. This technique uses a diminished chord which root is half step below the target, followed by the target chord dominant 7 chord. This method can be applied for most cases and can also be expanded to precede the dominant 7 chord by a Sus4 chord with the same root of that Dominant 7 chord.
Method #3: Diminished –Dominant motion to original chord relative minor. This is used when we are modulating from a Maj chord to its relative minor, such as from C Maj to A Minor. It also uses a diminished chord which root is half step below the target followed by the target dominant 7 chord, using the diminished chord root as the bass note.
Method #4: Dominant Chord modulation on common note. This implies that we check for a common note between the original chord dominant 7 chord and the target dominant 7 chord, so that to apply them in sequence and maintaining that common note as a transition point. This is particularly effective when we would like to modulate the piece in one whole step up or down, since the dominant chords common note is the root and the Minor 7th of the dominant chords, such as G to A7. The common note here is G (G is root of the G Chord and also it is the Minor 7th of the A7 chord) so both chords can be used in sequence to modulate from C to D.
Before we sign off please check the video included which displays audio and music sheet examples of the methods described above. Here is the link https://youtu.be/ErT0GP_e4ck
