Notice that the progression of chord roots on successive downbeats still matches the purely diatonic sequence shown in Example 1: G–F♯–E–D.Įxample 2. While the sequence contains chromatic chords (the secondary dominants), it is not a truly chromatic sequence because the overall trajectory of the sequence is still one that traverses the scale steps of a single key. Example 2 shows the same descending-fifths sequence, this time with alternating secondary dominant chords. Importantly, chromatic sequences are not merely sequences that contain chromatic pitches. The sequences derive from those that divide the octave equally.The chords within the pattern are of the same quality and type as those within each successive copy of that pattern.The chords that initiate the sequence model and each successive copy contain altered scale degrees.It would become a chromatic sequence.Ĭhromatic sequences differ from their diatonic counterparts in a few important ways: The sequence would rather quickly bring the music outside of the key of G major, and into new chromatic territory. If the interval between successive chord roots was consistently a perfect fifth/fourth, the root progression would be as follows: G–C–F–B♭–E♭–A♭–D♭… and so on. We “cheat” in the sequence in this way in order to keep the music within a single key. For example, the root progression between the IV and viio chords is an augmented fourth, whereas the root progressions between every other pair of chords is either a perfect fifth or perfect fourth. Because the sequence uses chords entirely from the key of G major, the root progressions don’t match exactly throughout the sequence. The sequence model, a root progression by descending fifth, is transposed down by second in each subsequent copy of the model.
Chord voicings should match between all corresponding components.Ĭonsider the following two-chord sequence ( Example 1), often referred to as the “descending-fifths sequence.”Įxample 1. Remember, with all sequences, the voice leading must be consistent within every voice.Diatonic sequences preserve the interval size, but not the quality, to ensure that they stay within a single key. Chromatic sequences differ from diatonic sequences in that both the size and quality of the interval of transposition is maintained throughout the sequence.These sequences avoid strict transposition of both interval size and quality. Chromaticized diatonic sequences include can include chromatic embellishments or chromatic chords, such as applied (secondary) dominants.Diatonic sequences repeat musical segments and are transposed in a regular pattern within a key.
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