Modal Interchange

     In this post, I will be showing you how you can effectively use modal interchange and add variety to your chord progressions and (re)harmonizations. This is a technique that consists in temporarily borrowing chords from a parallel tonality or mode that shares the same root, as a way of adding color and variety through the use of altered chords, without abandoning the established key.

     Although the most commonly used borrowed chords originate from the major and/or minor parallel modes, including the respective harmonic and melodic minor as well as symmetrical scales sharing the same root, there is no reason to limit yourself to these since the premise is that modal interchange can occur with any mode that shares the same root – i.e. E Dorian and E major:

     Even though borrowing chords introduces chromatic tones in a given key center, they are brief enough not to imply modulation so that the sense of tonic is not lost. Nevertheless, their use may be considered as transitory modulations but they are distinct from secondary dominant chords, for instance.

     The reason why is because borrowed chords from parallel modes share the same tonic and, depending on the parallel mode, it will have more or less common pitches. Consequently, modally borrowed chords sound like they are part of the same family due to their tonic relationship.

     Going from one parallel mode to another may be accomplished by directly introducing the borrowed chord in the chord progression, by using common pitches shared between the respective parallel modes and using chord transformations to smooth the process of modal interchange:

Oscillating between E dorian and E lydian

     Modal interchange chords can be used in different ways, such as adding color; reharmonizing sequence; as pivot chords for modulation; or as a link between two diatonic chords.

     When using this technique, it is important to make sure that the original key is clearly established before and after using borrowed chords. Also, making an extended use of borrowed chords may dilute the sense of tonality or lead to an unwanted modulation, unless your goal is to actually modulate through the use of this device.