In the fourth instalment in this series I will be focusing on the technique of circular sequences. For those that are unaware what a circular sequence is, I will explain. A circular sequence starts from a specific point, most commonly a mode of either the Major or Harmonic minor scale and follows a sequence of changes without crossing back on itself until it reaches the point where it began. For example:
C Major – A Harmonic minor – A Melodic – A Major – D Major – G Major – C Major
In this simple sequence, the G is raised to get to A Harmonic minor, then the F is raised for A Melodic, then the C to A Major and then a move back through the circle of fifths until the original key of C Major is reached. When the modulations occur without a doubling back to the scales played before it is known as a circular sequence.
The possibilities are literally endless, but here are some examples that are well worth exploring in your own music. I would recommend working out changes like the ones below and keeping them in mind when composing or working out a solo.
1) This is from the first prelude in C Major from Bach’s Well tempered clavier. A deceptively simple piece but it contains the following sequence:
C Maj- G Maj – G Mel - D H. Maj – D H. min – D H. min b5 –
D Mel b5 – C H. Maj – C Maj
Notice the use of Harmonic minor b5 and Melodic b5 scales, not as unusual as one might think. The sequence goes:
Forward a fifth to G Major, parallel minor of G Melodic, raise the C to D Harmonic Major, parallel minor, drop the fifth then raise the 6th for D Melodic b5. Finally, drop C# and then raise the Ab to arrive back in C Major. Simple.
A H. min – A Mel – A Maj – A H. Maj – D Maj – E Mel – E N. Maj – E N. min – A H. min
We start with (+1) alterations, raise the F to F#, then the minor third C to the Major C# to get to A Major. Then drop the F# to Harmonic Major and then raise it again at the same time as dropping the G# to G. Now we are in D Major and raise D to get E Melodic, then the twist. Drop the F# for E Neapolitan Major, then the drop the C# for E Neapolitan minor and finish with a simultaneous modulation, drop D# to D and raise G to G#, and voila. Home again.
3) This one comes from the piano sonata in C, K330 by Mozart. It is a great sound and one that shows that the use of the Melodic b5 scale once again, and the fact that it was being used to create an unusual change back in the 18th century, and would become such a popular scale of choice by composers such as Leo Brouwer, William Walton and Toru Takemitsu:
A H. min – A Mel b5 – G H. Maj – G Maj – C Maj – D Mel – A H. min
First, a simultaneous modulation. Raise the F to F# and drop the E to Eb to get A Melodic b5. Nice. Then drop the G# to G and raise the Eb to E to move into G Major. Then it is simply back a fifth, to C Major, raise the C to C# and finish with another simultaneous modulation of raising the G to G# and dropping the C# to C. Bookended with simultaneous modulations. Tasty. One of the hallmarks of the classical period of music as far as modulations are concerned is the increased use of simultaneous modulations instead of incremental changes. But more on that in a later post.
4) This is one of my own circular sequences and includes enharmonic equivalent scales.
C Major – C H. Major – A H. minor – E H. minor – C Mel b5 – G Maj – C Maj
Here, I am starting with the change to C Harmonic Major by flattening the 6th and then substituting the scale for its enharmonic equivalent of A Harmonic minor, the Ab in one scale changing to the equivalent of G# in the next.
Then forward a fifth to E Harmonic minor (E F# G A B C D#) and then the enharmonic equivalent scale once more of C Melodic b5 (C D Eb F Gb A B), the F# and D# in one scale is replaced by the Gb and Eb in the other. Next, the Gb is switched to F# whilst the Eb is raised to get to G Major and back a 5th, and voila. C Major.
5) Finally, a variation of the ground breaking sequence that occurs in the section of the Chaconne in D minor by Bach that modulates from D Harmonic minor to D Major. Here I have altered it for use as a circular sequence:
D Harmonic minor - D Harmonic Major – G Melodic – F Major – C Major – F Major – Bb Major – A Loc nat7 – D Hungarian minor – D Harmonic minor
First, the shift to parallel Major and then the C# is flattened to reach G Melodic. Drop the F# to F and then back three times through the circle of fifths to Bb Major. Raise the G to G# for A Locrian 7 then a simultaneous modulation of raising the Eb to E and C to C# for D Hungarian minor followed by a flattening of the G#. Works well in many musical settings and one that is bound to impress anyone who is listening.
Next up, I shall be cooking with symmetrical sequences, so stay tuned.
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