Altered 2 5 1 Progression With Modes
The 2 5 1 chord progression, also referred to as II – V – I is a common chord sequence that is used in a wide variety of music and genres and is best known in Jazz harmony. This progression follows its roots up in 4ths for example in the key of C major the II chord would be Dm traveling to the V chord G major and finally to the I chord C major. If using four part chords this example would be the II chord Dm7 traveling to the V chord G7 and finally to the I chord Cmaj7 . Another term that can be used would be the supertonic the II chord Dominant the V chord and finally the Tonic or the I chord.
In a 2 5 1 progression jazz players often substitute the 5 chord with another dominant chord a tri tone away (a flat 5th up or down from the root.)
Dm7 – G7 – Cmajor7th – Traditional harmony
Dm7 – Db7 – Cmajor7th – with a Tri-tone substitute
Why does this work? In a G7th chord the notes would be G, B, D and F. The two notes that really matter are the 3rd and the b7th highlighted in red. When you substitute the G7th for the Db7 the notes are Db, F, Ab and B the 3rd and the b7th tones are the same as the G7th. So both chords share the most important notes, so it really doesn’t change the quality of the 2 5 1 sound as much as you would think.
The bass line also has a very appealing sound that moves chromatically down to the tonic chord.
In this video I will demonstrate the traditional 2 5 1 chords, as well as the altered 2 5 1 progression, in addition I will demonstrate the scales that would typically accompany these chords. Keep on playing and enjoy