# Modal Workshop: Intervallic Structures

February 15, 2011
I’d like to introduce you to a very useful way to expand your chord vocabulary. The voicings we are about to explore work really well for comping and also for harmonizing melodies in a bunch of different musical contexts. All of the following examples are in E Dorian, so you can use the low open-E string as a drone. It is very helpful to be able to hear how each of these chords fit harmonically within a key. But before we get into the chords, let’s take a look at the E Dorian scale. I tend to think of this scale in one of three ways:
• As a D major scale starting on the second degree (E).
• Following the formula for a Dorian scale based off of E major (1–2–b3–4–5–6–b7).
• Simply by the names of the notes: E–F#–G–A–B–C#–D.

Personally, I tend to gravitate toward the scale-degree formula. It simply makes it easier to translate anything you work on into all 12 keys. We are going to think of an intervallic structure as a combination of intervals within a given scale. This structure can then be sequenced through the entire scale, which will result in seven different voicings. Sound complicated? Let’s break it down:

In Fig. 1, you see the notes of an E Dorian scale on the 1st string. Once you have learned these E Dorian notes on the 1st string, take a few minutes and find the same notes on the other five strings.

Next, we’ll try out some two-note intervals (also known as double-stops). Let’s take the interval of a sixth and move it through the entire scale. In Fig. 2, I have shown how to play these on the top two strings. Note that when referring to intervallic structures we talk in terms of diatonic intervals, so we will end up with different qualities (major, minor, etc.).

In Fig. 3, I expanded this idea and added two more notes to the voicings. I used the sixth from the previous example and added a fourth and a second. From low to high, this voicing is based on a fourth, a second and a sixth. Again, I move this structure through the entire scale and, voilà, we now have seven voicings that can work for E Dorian!

Not all of the voicings in Fig. 3 are complete Em7 voicings, some are a bit ambiguous because they are missing the 3rd and/or the 7th, but that’s exactly the point. They work perfectly in a modal context and could be used more as a textural device. Once the key center and mode is established, we don’t have to constantly use “descriptive” voicings. I always tell my students “Don’t put a bagel on a bagel!”

You can also use your intervallic structures for modes other than Dorian. Just be aware, that some modes have an avoid note, for example in Ionian you have to be careful with voicings that contain the 4th. As always, use your ear to judge what fits.

The most common intervallic structures would be quartal harmony (also known as 4th chords). These chords consist of two stacked diatonic fourths. In Fig. 4 you can see these chords on strings 4-3-2 in E Dorian. Download example audio...

What’s next?
• Learn one intervallic structure in the seven modes derived from the major scale.
• Move these around to all 12 keys.
• Apply the same concept to melodic minor or other scales.
• Finally, put some rhythm to these chords.

Every intervallic structure has its own sound. Deciding which structures are suitable for your style of playing is a matter of personal taste. Once you’ve learned a couple of different intervallic structures, start mixing and matching them. This is when it gets exciting—you will discover an entirely new textural quality to that good ol’ one-chord vamp!

Alex Machacek
Originally from Austria, fusion guitarist Alex Machacek has a BA from the Berklee College of Music and currently teaches at the Guitar Institute of Technology in Hollywood. His latest project is 24 Tales, a duo album with drummer Marco Minnemann. For more info visit alexmachacek. com.