You may have heard about modal inter­change in pass­ing, but never had it explained. If you want to know what it is then you have come to the right place. I’m going to quickly break down for you what modal inter­change is all about and what it can do for you in song­writ­ing. In short Modal Inter­change is the act of replac­ing chords in a har­monic pro­gres­sion with other chords belong­ing to par­al­lel modes or scales to the key in which the song is writ­ten. Quite a mouth­ful, but don’t worry, it’s really easy. So if we’re replac­ing chords with ones that don’t belong in the key, aren’t we adding wrong notes? Why would we want to do that? Well, by using notes that don’t belong to the key that the song is writ­ten in you are adding what is known as “chro­matic inter­est”, which is just a fancy way of say­ing that you’re adding the unex­pected. To put it another way, you are ‘jazz­ing up’ your piece.

How It Works

There are two ways in which the major and minor keys (which are two classes of modes in the dia­tonic sys­tem) are related to each other, they can be rel­a­tive or par­al­lel to one another. Say we’re start­ing with a major key, the rel­a­tive minor has a dif­fer­ent tonic note than its major coun­ter­part yet has the same key sig­na­ture ( the pat­tern of sharps or flats). To start with the sim­plest exam­ple the key of C major has no sharps or flats, the key of A minor also has no sharps or flats. This makes A minor the rel­a­tive minor of C major. In this dia­gram of the cir­cle of fifths, the inner cir­cle shows the rel­a­tive minors of the outer circle.

Click to learn more about the Cir­cle of Fifths.

Now as you can see if we were to try to use a rel­a­tive key to bor­row chords from it wouldn’t add any chro­matic inter­est as you would not be intro­duc­ing notes into your piece that aren’t already in the key in which it was writ­ten. In con­trast, the par­al­lel minor has the same tonic note yet dif­fer­ent key sig­na­tures. In this case C minor is the par­al­lel minor of C major. They both start on C, but the C minor scale has three flats (A-flat, B-flat, E-flat). On a quick side note: I’ve been speak­ing of par­al­lel and rel­a­tive minors, but the inverse rela­tion­ship applies as well. C major is the par­al­lel major of C minor and the rel­a­tive major of A minor. Par­al­lel and rel­a­tive just describe the type of rela­tion­ship two keys have. So remem­ber: par­al­lel — same tonic note, rel­a­tive — same key signature.

That you use a par­al­lel key to bor­row from is the secret behind modal inter­change. The pat­tern of inter­vals that make up a key is termed its mode. Of the seven modes (Ion­ian, Dorian, Phry­gian, Lydian, Mixoly­dian, Aeo­lian, and Locrian) in com­mon use in tonal music, the major scale cor­re­sponds to the Ion­ian mode and the nat­ural minor scale cor­re­sponds to the Aeo­lian. So what you are doing by sub­sti­tut­ing chords and notes with those from a par­al­lel key is lit­er­ally inter­chang­ing the chords and notes between modes.

I think that I should be clear on some­thing here. So far the dis­cus­sion has lim­ited itself to bor­row­ing between two spe­cific modes, the Ion­ian and the Aeo­lian. To be cer­tain, there is no rule that you must limit your­self so in modal inter­change. Indeed you can bor­row from any mode you please with vary­ing degrees of suc­cess. I sug­gest try­ing the Phry­gian next.

Modal Inter­change in Action

Let’s run through a quick exam­ple of what sim­ple modal inter­change might look like. Here is an easy pro­gres­sion in C major (Ion­ian mode):

C (I) / G (V) / F (IV) / Am (VI)

Play it through to see how it sounds. Now we’re going to make a slight alter­ation by replac­ing the G chord with it’s coun­ter­part in the C minor scale (Aeo­lian mode). Play this one through and lis­ten to how the tone of the pro­gres­sion changes.

C (I) / Gm (v) / F (IV) / Am (VI)

Notice how the pro­gres­sion becomes more ‘seri­ous’ and less ‘light’, yet we don’t have to leave the major key to obtain this effect (com­pletely leav­ing one key for another would be mod­u­la­tion). By just includ­ing the B-flat in the Gm chord tem­porar­ily, we can avoid wan­der­ing into the ‘sad’ sound of a full-on minor key. In a sense we are mak­ing the key less dis­tinct with­out aban­don­ing it com­pletely. Thus modal inter­change is a great way to spice up your song’s har­mony; it becomes less pre­dictable and more expres­sive than it would be if you stuck com­pletely to one mode. In its own right, the nat­ural exper­i­men­ta­tion with modal inter­change will shake you out of the rut you’ve made for your­self of using the same chords over and over again. Think of it as a way to squeeze the cre­ative juice out of your brain.

If you need some ref­er­ence as to what chords go with what scales check out my chord trans­po­si­tion chart, and here is a great post on build­ing pro­gres­sions and chart­ing the chords that belong to cer­tain modes.

Tags: Creativity, Modes, Music Theory, Songwriting

This entry was posted on Saturday, April 18th, 2009 at 1:24 pm and is filed under Everything Else. You can follow any responses to this entry through the RSS 2.0 feed.