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The Shape of Things to Come

By Troy Stetina
GuitarOne Issue 2 - 1996
Updated and rewritten (c) 2020 Troy Stetina

The guitar is a shape-oriented instrument. That is, notes form readily identifiable shapes, or patterns, on the fretboard. And each of these shapes has its own particular sound or quality. So what's the significance of this? Well, not too much except. . . maybe, it's the key to unlocking the secrets of the fretboard, the key to developing your ear for learning how to play songs simply by hearing them, and the key to knowing exactly where on the fretboard to find the sounds that you dream up in your own imagination! Shall I go on? Well, you get the picture. It's important. So it's something you should know. In fact, it's critical if you take your guitar playing seriously. (And I know you do.) So let's take a closer look at this whole shape thing and see if we can make some sense out of it.


Getting Started

Fig. 1, below, shows each two-note shape based on the pitch of A up to the octave. These are called intervals. Now before you blank out staring at all these technical interval names, keep in mind that you don't have to memorize them all just yet. This is mainly for reference. This is so you can see them all lined up together and find their names quickly.

As you play through them, notice how they grow a half-step (one fret) taller each time, The first interval, unison, consists of two notes of the same pitch. Moving up one half step, or one fret, we arrive at the minor second interval. Notice the two different shapes of the minor second depending on whether it is played on two different strings or on the same string. Next is the major second, which also has two different shapes. Continue on through the rest of the intervals--minor third, major third, perfect fourth, diminished fifth, perfect fifth, minor sixth, major sixth, minor seventh, major seventh and octave.


As you've just seen, notes may sometimes fall on the same string. Now, two notes on the same string can't be played together at the same time, of course. This points to another important aspect of intervals. They can appear either with the notes sounding simultaneously, as in a chord, or they can appear with the notes following one another, in sequence. When the notes are played together, we call it a harmonic interval, and when the notes are played in sequence, we say it is a melodic interval.

We should also point out another set of terms often used in describing intervals before we move on, and that is dissonance and consonance. Notes that do not blend together nicely--that is, they sound unstable or "messy" when played together--are said to be dissonant. Notes that do blend together well are consonant. A more distorted guitar sound will accentuate the dissonant qualities of intervals, but in general, unisons, octaves, fourths, fifths, thirds and sixths are considered consonances, while seconds, sevenths and diminished fifths are dissonances.

Now that you're armed with the basics, you're ready for battle, So let's tear into each shape in detail, starting with the ever-present power chord, perfect fifth.

Fifths, Fourths, Octaves and Unisons:

The most common shape played on the guitar is undoubtedly the perfect fifth. You're probably already quite familiar with this one since it's the basic two note power chord found at the heart of so many rock and metal tunes. It has a rather hollow or stark sound and gives us a powerful consonance. Among the many possible examples we could cite that rise perfect fifths is the opening progression of the Offspring's "Self Esteem," shown in Figure 2, below. Notice the consistent shape of the fifth dyads (two note chords) in the A5, F5, C5 and G5 power chords.


Next, let's hunt for some perfect fourths. If you take the typical three string power chord shape and omit the bottom root note--presto! You have the interval shape of a perfect fourth. Figure 3, below, shows this graphically.


Figure 4 is Deep Purple's classic, "Smoke on the Water" riff, which employs these fourth-dyad power chords. Fourths are somewhat similar in sound quality to fifths in that they also have a certain "hollowness," or lack of color. But fourths have a thicker, somewhat unresolved interaction between the notes. (If fourths are played near the low end of the guitar register, they become quite dissonant.) Play fifth and fourth intervals alternately and compare their different vibrations.


Our third target is the octave shape. If you look again at the three string power chord shape back in Fig. 3, above, you'll notice that still one more interval can be found lurking within that pattern. It's the octave shape, spotted by skipping the string in the middle and going from the lowest note directly to the highest note. A characteristic of octave intervals is that both notes will have the same letter name. The opening guitar line of Jimi Hendrix's tune "Fire" employs octaves, as shown in Figure 5, below. To play octave intervals harmonically like this, simply mute the middle string and strike the three strings together. Listen for the relatively thin quality of octaves, as the wave form of the higher note fits perfectly within that of the lower note. Other great examples of octave playing include the work of jazz great Wes Montgomery, as well as music by Steve Vai ("Big Trouble"), Paul Gilbert ("Anything for You") and Stevie Ray Vaughan ("Riviera Paradise").


The riff from Led Zeppelin's "Immigrant Song" Figure 6 (below) shows octaves at work in a melodic context. Notice how the quality of the interval is transformed when it appears as a melodic leap instead of a chord dyad.


Closely related to the octave interval is the unison interval. Two notes in unison are not only the same letter name, they are also found in the same register. In other words, they are the same pitch. Unison intervals are common in blues-influenced licks, often in conjunction with string bending. But they may also appear through the use of open strings, with no bending involved. The opening of Stevie Ray Vaughan's "Pride and Joy," as shown in Figure 7 (below), demonstrates this.


At this point we've covered the so-called perfect intervals: the fifth, fourth, octave, and unison. These all fit together nicely, and you can think of them as belonging to a family, or group.

The Diminished Fifth:

The diminished fifth, or augmented fourth, is the heavy interval. Also known as the tritone, the twisted sound of this interval can be heard working its wonders throughout the metal vocabulary. As a harmonic interval, it gives us the strongest dissonance. Listen for its dissonant character in Satriani's "Crushing Day" in Figure 8, below. You can't miss it. Although the shape is just one fret away from the perfect fifth, the sound is worlds apart. The riff tosses you back and forth, from the clearest consonance to the harshest dissonance. For more on diminished fifths, see the lesson on dissonance.


The opening of Rush's classic instrumental "YYZ" gives us an excellent example of the melodic use of the diminished fifth, as shown in Figure 9, below. Here you'll notice its odd melodic quality instead of its grinding harmonic dissonance. Listen for the characteristically odd melodic leap and overall feeling of tension and lack of clear direction or foundation. Other prominent examples of the tritone in a melodic context can be heard within the main riff of Metallica's 'Enter Sandman," as well as at the end of each verse line of Nirvana's "Heart Shaped Box."


Figure 10, Black Sabbath's "Symptom of the Universe" draws on the darkest aspects of this interval by building power chords onto the twisted, melodic diminished fifth. This type of melodic usage of the diminished fifth interval has become a mainstay of the heavier rock styles. The music of Metallica is full of them. For example, listen to the verse riff of "Sad but True" for another demonstration.

Thirds and Sixths:

Now let's move on to the more colorful intervals - thirds and sixths. Look for the melodic appearance of a minor third between F# and A, bracketed within the main riff of Nirvana's "Come As You Are" (Figure 11, below). It may not be immediately apparent due to the fact that A is played as an open string, but if you hold one finger over the nut at the A string, you will readily see the minor third shape emerge. Keep in mind that open strings don't really change any of these interval shapes. They simply enable you to play one of the notes without fingering it. The same effect occurs with the perfect fifth, also bracketed, incorporating the open low E string. The fifth shape and minor third shape form a kind of mirror image of one another. Notice their similar, yet opposite, patterns.


The Scorpions' classic "The Zoo" utilizes a harmony in parallel thirds, meaning that each note is harmonized with another note a third above it within the key. Consequently, it uses both major and minor third shapes (Figure 12, below). Listen as the harmonized thirds of the riff move down and back up the scale. The minor thirds seem darker than the major third, which feels stronger and brighter. Other similar examples of parallel thirds include the main themes of The Beatles' "And Your Bird Can Sing" and Yngwie's "Black Star."


Sixths are closely related to thirds. In fact, thirds can be transformed into sixths by inverting them; that is, raising the bottom note an octave, thereby putting it on top of the other note and, in effect, turning the interval upside down, Specifically, a major third inverted becomes a minor sixth. This is shown graphically in Figure 13, below.


Now if we consider this major third, A-C# (shown in Fig. 13), to be part of an A major chord (incomplete) for a moment, then its inversion -- the minor sixth -- is likewise part of an A major chord. The only difference is that the C# is on the bottom and the root, A, is on the top. Chords with their third (the chord tone a third above the root) on the bottom like this are said to be in first inversion and are written with a slash symbol. So this minor sixth shape can be used as a first inversion A major chord, or A/C# (read "A over C# "). 

Minor sixths are quite often used as first inversion major chords as shown above. Figure 14, below, shows this chord -- first inversion A major -- as a minor sixth shape at work in the chorus riff of Van Halen's "Feel Your Love Tonight." Notice how the minor sixth dyad sounds as though it wants to pull toward a perfect fifth, which is exactly what it does in this case, as the lower note moves up one fret to form the following D5 power chord.


Next we come to the major sixth shape. This interval is most commonly seen within the basic blues comping figure. Incorporated by early roots rockers like Chuck Berry and Elvis, blues comping figures spread throughout the rock idiom. They appear commonly in the music of the Beatles, the Stones, Clapton, Aerosmith and Kiss, for example. In Figure 15, below, you can see the basic sixth comping figure, which alternates between fifths and major sixths, in the Beatles' classic "Come Together."

Seconds and Sevenths:

Finally, we arrive at seconds and sevenths, our last set of intervals. A minor second is a one-fret interval, also known as a half step. A major second is a two-fret interval, the same as a whole step. Figure 16 (below) shows the verse riff from Metallica's "Enter Sandman," which uses both a minor 2nd and a major 2nd in a melodic context. The minor second is found in the root movement between E5 and F5, while the major second occurs between E5 and F#5.


The minor seventh is one whole step less than an octave. Figure 17 (below) is Alice in Chains' driving groove from "Man in a Box." It contains a perfect example of the minor seventh in a harmonic context. Listen for its characteristic flavor, slightly unsettled yet firmly attached to its E foundation.


And last, but not least, we arrive at the major seventh -- just a half step less than an octave. Metallica's "One," shown in Figure 18 (below), demonstrates this nicely in the 2nd and 4th measures.


Well, that covers all the interval shapes within the octave. Now, as you learn riffs and songs from this point on, mentally take notice of the shapes you see, and you'll begin to get a better feel for the distinct qualities of each interval shape. Ultimately this will enable you to visualize how riffs are played on the guitar even before you touch your instrument!

For more on intervals, ear training, harmony, and mastering all fretboard shapes and scales, see Fretboard Mastery.

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