One of the more common procedures found in metal music is harmonization in parallel thirds. We often hear this in the guise of two guitars playing a melody or dual guitar solos (with one guitar playing in parallel thirds above the line of the other guitar), and we also hear this harmony being used within riffs (with the harmony being played within a single guitar part). This type of harmony is an example of a dyad—an instance of two different pitches being played together—and the reason it is classified as parallel thirds is because the notes of the harmonic line are consistently played a third above the root melodic line.
When parallel third harmonies are constructed, they are typically based rather strictly on the notes of whatever mode is in play. As a consequence, the quality of the parallel third harmony—i.e. whether it is a major or minor third—may change from note to note (the reason being that the notes of common modes aren’t uniformly spaced, so the quality of particular harmonies fluctuates with the change in root note). For example, in the case of E natural minor, parallel third harmonies appear as a succession of major and minor thirds as below:
An alternate, and interesting, way to approach parallel harmonies is to play strictly one quality of the harmony, such as strictly major thirds or strictly minor thirds. The consequence of this is that the coherence of the underlying mode may be sacrificed, and this could be a very useful and desirable effect as it may produce some unexpected and unpredictable notes for the listener.
We find examples of this type of effect in Megadeth’s “Holy Wars…The Punishment Due”, which is among the finest metal songs ever written and exemplifies the incredible riff-writing of guitarist Dave Mustaine. In some of the song’s riffs, parallel thirds are played strictly in one quality, which adds an unusual flavor to the E minor setting. Additionally, we find power chords—i.e. parallel fifth dyads—being juxtaposed to parallel third dyads based on the same root note, which offers the listener two different versions of a dyadic progression.
The first example occurs in the riff that appears at 1:08 in the song. The riff opens with power chords on a progression alternating between F# and G. The notes that fall above the F# and G—namely, the C# and D—are notes that belong to the E Dorian mode and are somewhat ordinary within a traditional E minor key setting. Hence, we hear them without perceiving any disruption to the E minor key:
When that progression returns, the power chord dyads are replaced by major thirds:
The switch to major thirds offers a different flavor of this riff. The chief culprit is the A# that falls above the F#, for this A# is classified as the tritone to the tonic note of E and does not fall within the traditionally-expected setting of the minor key. Because of that, we perceive the A# as disrupting the otherwise normal E minor key setting. (Even though we are accustomed to tritones being utilized freely in the minor key fabric of metal songs, our ears still respond to their inherent dissonance). Hence, between the two versions of the F#-G progression, we hear a juxtaposition between the normal-sounding power chords and the slightly discordant major-third setting.
There is an even greater mixture of dyads in the verse riff (starting at 1:28). The verse riff is characterized by a recurring, ascending, three-note chromatic motive and gallop attacks on the low E string, with dyads interspersed throughout. The dyads in each measure appear as follows:
- First measure: major thirds on G-F#. As with the riff at 1:08, the A# that falls above the F# sounds dissonant within the E minor tonality.
- Second measure: minor thirds on A#-B-A#. The notes that fall above A# and B—namely, C# and D—are themselves acceptable in the E minor tonality (as part of E Dorian mode). However, the root note of A# is, as explained above, dissonant in E minor. Furthermore, though the minor third on B is reasonable within E minor, it is less expected and less powerful harmonically than the major third on B minor that we are accustomed to hearing. (The major third is part of the full major triad on B that constitutes the dominant V chord in E minor).
- Third measure: minor thirds on E-D#. All of these notes are expected in the E minor tonality (as part of the harmonic minor mode).
- Fourth measure: major thirds on F#-G (similar to first measure)
- Fifth measure: major thirds on A-G-A. All of the notes are reasonable in E minor (as part of E Dorian mode).
- Sixth measure: major third on Bb. The Bb is enharmonically equivalent to A# and hence also represents a tritone to the tonic of E. The D that falls above is normal within E minor.
- Seventh measure: major thirds on Bb-A. Again, the Bb is a tritone to the tonic E. We could possibly explain the Bb-A motion as indicating the Locrian mode, but the C# above A is not part of the E Locrian and hence would upset that definition.
- Eighth measure: perfect fifths (“power chords”) on Bb-A. With the F and E that fall above the Bb and A, the notes now fully correspond to the E Locrian mode (unlike the previous measure).
These various dyads contribute to an impressive diversity of sounds within this riff. Not only do the different dyads (major thirds, minor thirds, and perfect fifths) have unique sonic qualities, the different approaches to the minor tonality (Dorian modality, harmonic minor modality, free usage of tritone, and Locrian modality) also create a mixture of different modal and harmonic references. Similar to the example at 1:08, there is also juxtaposition between two progressions on Bb and A: in the seventh measure, on major thirds; in the eighth measure, on perfect fifths.
As complex as the impact of these dyads seem, they are the result of the rather straightforward approach of using parallel harmonies of a particular quality. This strict parallelism undermines the concept of an overall modality and allows for unusual results, some of which can be partially explained within other modal contexts and some of which are just plain quirky and inexplicable within a traditional modal framework. And when different qualities of parallel dyads are used in combination with each other, the results can be even more intriguing.
“Holy Wars” demonstrate how the diverse usage of strict parallel harmonies can arranged with particular artistry and to great effect, and the manner in which this technique is used likewise contributes to what makes “Holy Wars” one of the true masterpieces in metal.