11d Lesson - Tonal Sequences

Class Discussion

Further to our discussion of the importance of patterns in music, please view the following TED Talk by Dr. Scott Rickard. He used mathematics to try to create music without any repetition, and the results are…interesting.

Melodic sequences

As the class worked through creating the melodic sequences, I realized that I needed to clarify that the pattern itself does not need to be defined. When we are describing sequence, we assume that the reader is looking at the music and therefore can see the entire first iteration. Instead, we focus our description on how the pattern is transposed, not on describing the intervals within the initial segment.

Once this was clear, the class easily incorporated the terms in their description of the pattern because each term is used in a similar manner to previous units. The discussion of chromatic and diatonic sequences, however, required clarification.

• A true diatonic pattern only uses notes within the key signature so they do not require a quality when discussing the transposition. For example, it is incorrect to describe a diatonic pattern using, “The pattern repeats in ascending major 3rds,” because diatonic patterns will have a mix of major 3rds and minor 3rds depending on which scale degree the iteration starts. Instead, we would say, “The pattern is transposed in diatonic ascending 3rds,” because this tells the reader to go up a 3rd and use whatever note is in the key signature.
• Conversely, chromatic patterns do require a quality on the transposition for the interval, because the pattern repeats exactly using the same intervals from the initial iteration. If we isolate the third sequence from the melodic examples (see example below), we have a fixed intervallic pattern – in this case, descending m2, ascending m2, descending P4 – that is then repeated by transposing that exact intervallic pattern down a m2. In short, a chromatic pattern is assumed to transpose every part of the pattern exactly at a fixed interval(s) unless otherwise noted.

The fifth example was the most difficult to complete and classify, because it mixes elements from both diatonic and chromatic sequences. It has a diatonic transposition, but it resembles a chromatic sequence because there is a fixed intervallic structure within the pattern. We could say that it is a diatonic sequence that descends in 3rds, but uses a fixed chromatic pattern within each iteration. The biggest problem lies with the fifth iteration because it is the only pattern that requires an altered fourth pitch rather than just a raised second pitch. There is not technically a “right” answer to this; it would be decided by the context and style in which the composer was using the pattern. In the completed example below, I chose to complete it using an F♯, because it creates a nice leading tone for the following pitch. If the pattern had been repeating at the second rather than third, the next pitch would have been an A, and I would likely have chosen an F♮.

Harmonic sequences

Ex: Harmonize a two-voice sequence Upper line: C5 - F5F5 - E5__E5 - D5D5 - C5__C5 - B4 - C5 Lower line: C3 - A3 - G3 - G3 - F3 - F3 - E3 - E3 - D3 - D3 - C3 Roman Numerals: I - IV6 - V7 - I6/4 - IVM7 - viio6/4 - iii7 - vi6/4 - ii7 - V6/4 - I

• the underscores indicate tied notes
• the tied notes are a string of 7-6 suspensions
• once you establish a pattern in the chord progression you have to stick with it for the sequence to work
• the sequence in this progression is a string of 6/4’s and 7th chords
• it is also a series of descending diatonic 5ths

In the same example, add an alto line: Soprano: C5 - F5F5 - E5__E5 - D5D5 - C5__C5 - B4 - C5 Alto: E4 - C5 - B4 - C5 - A4 - B4 - G4 - A4 - F4 - G4 - E4 Bass: C3 - A3 - G3 - G3 - F3 - F3 - E3 - E3 - D3 - D3 - C3 Roman Numerals: I - IV6 - V7 - I6/4 - IVM7 - viio6/4 - iii7 - vi6/4 - ii7 - V6/4 - I

What is the sequence?

• root movement descends by diatonic 5th
• alternating between root position 7th chord and second inversion triad
• each chord lasts two beats

When looking at diatonic sequences, always identify them by root movement.

Ex: Identify the harmonic sequence Soprano: E5 - D5 - C5 - B4 - A4 - G4 - A4 - B4 Alto: G4 - B4 - E4 - G4 - C4 - E4 - F4 - D4 Bass: C4 - G3 - A3 - E3 - F3 - C3 - F3 - G3 Roman numerals: I - V - vi - iii - IV - I - IV - V

Sequence Patterns:

• descending 4th followed by ascending 2nd (through the third bar)
• diatonic
  • it works best to describe a sequence including as much of the musical material as possible

A sequence, as long as it is strict, can break harmonic rules.