Many guitarists use chords for rhythm guitar without considering another option: intervals. While a chord is three (or more) notes, an interval is only two. This might seem a trivial difference, but using just part of a chord lets you play intervals for specific reasons, and using only two fingers creates other more advanced possibilities. Let's take a look at chords and see the two main intervals at our disposal.
It may seem that with only two pitches, the sound would be thinner than a chord, but hard rock and metal players have been going with two notes for decades. A healthy distortion more than makes up for it.
The full barre chord is already avoided mostly because many players feel the higher notes don't sound good with distortion. Significantly, one of the higher pitches omitted is the chord's third. In theory, all chords have at least a root, third, and fifth. Simply put, the third is what makes a chord major or minor, so without it, you have a somewhat empty voicing, which is why it sounds more stable and more powerful (not less) with distortion.
Consider the case of the octave, which is the same note at a higher or lower pitch. All octaves are "perfect", and along with the unison, are as stable as an interval can be. Similarly, the fifth is also perfect (usually) and also very stable. When distortion is added, this stability is exaggerated. This is why the "power chord" of root-fifth-octave is a "can't miss" voicing that always sounds strong.
In the same way, the sound of a third is also exaggerated, but it is a less stable interval, a fact that becomes increasingly apparent if the interval is held alone for several seconds. The interval will "shake" just like when you're tuning the guitar, a dissonant effect that is tolerated by some listeners more than others. It is less noticeable in the midst of a larger chord, but with the third removed, stability is easier.
If a rhythm guitarist is not going to play chords or single notes, there are several intervals to choose from (this list is presented in the order of increasing dissonance and decreasing stability):
Our purpose is to use parts of a chord instead of the entire thing, so our two main choices are fifths and thirds. The other intervals will still be used when we get to ornamentation, but let's have a look and listen to our core intervals.
For most guitar players, the fifth needs no introduction. It's what you get when you only play the two lowest notes of a barre chord (Example 1).
As shown in the example, some also play the octave, which adds some brightness and stability but otherwise has no effect. This is one reason many people don't play it, especially in heavier or darker music. Another reason to omit the octave is that, instead of using your pinky for that note, your pinky can hold down the fifth, which is a more comfortable hand position for many.
One advantage is that in standard tuning, the same hand position can be moved around the guitar neck without much thought. All a player has to do is know which notes are in the key, put the index finger there, and retain the same hand "shape". This has one unintended side effect, however. There is always one diminished fifth, not perfect fifth, in a key, but players tend to ignore this as if a fifth is a fifth is a fifth. In E minor, for example, the F# voicing should include a C natural, but most players use C#, introducing a raised sixth scale degree to the music (Example 2). This is fine, but be aware that this might affect lead guitar work.
You've probably heard this before, but for comparison, listen to this simple riff using all fifths.
MP3 - Fifths
The second mp3 is identical except it includes the octave as well. It should sound slightly brighter.
MP3 - Fifths With Octave
Thirds played alone are not very common, which is odd because thirds are the building block of chords, and one would expect to see them frequently. We can only guess the reason is the aforementioned effect of distortion, but the more likely reason is that no one purposely omitted the third when avoiding a barre chord's higher notes, so they haven't purposely played it alone either.
A big advantage to thirds is that they are richer intervals, with more tone color. They are moodier, more dramatic, and thicker.
MP3 - Thirds
In this mp3, the intervals are E minor 3rd, D major 3rd, and C major 3rd, as shown in Example 3.
Thirds come in two varieties: major thirds and minor thirds. This is more diverse than playing a perfect fifth everywhere, but is also one deterrent to using them. To play and/or write an entire riff in thirds, you must know which one you're supposed to play as you move through a key and change your hand shape accordingly. If a full chord would be minor, then you want to play a minor 3rd at each of those points. The same is true of major thirds. In E minor, the first, second, fourth, and fifth intervals would be minor, and the third, sixth, and seventh intervals are major: E minor, F# minor, G major, A minor, B minor, C major, D major.
The tonality of major or minor is immediately apparent, which can be useful for making a noticeable key change, such as from E major to E minor. If you were to do this with fifths in the rhythm, the change wouldn't be noticed at first. In addition, if you want to play an unexpected sound, such as using an E major chord where an E minor one is expected, using a third easily accomplishes this.
Like the fifth, thirds can also be played with the octave included (Example 4). Unlike the fifth, a third has more than just added brightness this way, for the character is changed somewhat.
MP3 - Thirds With Octave
This shape is unusually difficult to move around the guitar.
As mentioned earlier, the third is less stable than a fifth and sounds less desirable the longer it is held. One trick for using it successfully is to play it briefly. While this might seem too limiting, consider that many metal players have a palm-muting style like the audio examples. Notice how the interval is momentarily sounded in between muted 8th-notes, meaning it never has the chance to deteriorate. On the repeat, the interval is held open longer to provide a clearer example of the sound.
As a final note, thirds become muddier and less useful lower on the guitar, but this can be overcome with the above technique.
Switching between thirds and fifths can help provide variety within a riff and between two music sections. One simple trick is to take the same chord succession and do it twice: once using fifths and once with thirds. Another is to write two sections of music where the first interval is different. This helps creates separation between musical ideas.
Much more elaborate things can be done with intervals, as will be demonstrated in future articles, but to give you some idea, listen to these all-interval riffs from my album, The Firebard.
MP3 - All-Interval Riffs
Though chords and fifths are frequently used, the addition of thirds to your repertoire will give you other options, which is always a good thing. We've only touched the surface of interval riffs, but this simple technique can be the foundation for an empire of ideas. Stay tuned for more...
Randy Ellefson is an instrumental guitarist with endorsements from Alvarez Guitars, Peavey, and Morley Pedals, and a Bachelors of Music in classical guitar, Magna Cum Laude.
His most recent album, "Some Things Are Better Left Unsaid", was independently released in July 2007. Ellefson is also known for his extensive experience with tendonitis, which once took away his playing for five years.
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