Mastodon has emerged as one of the premiere bands in prog-metal today. Their past three studio albums, Leviathan (2004), Blood Mountain (2006), and Crack the Skye (2009) have all been met with critical acclaim and growing commercial success. Like other prog-metal bands, Mastodon’s music is characterized by performance virtuosity and compositional complexities. One area where they distinguish themselves is in their approach to tonality, in which they deftly weave in disparate elements with sophistication and artistry.
Their famed song “Blood and Thunder” from Leviathan exemplifies this process. E minor serves as the overarching key for the song, but they use different scales and non-harmonic tones that either compliment or contrast with that key. The result is a rich tapestry of tonal colors, a more sophisticated manner of presenting and interpreting the E minor key. (Note: the song is played with the guitars downtuned to D, but for purposes of interpreting this song as it is conceptualized on the fretboard, we’ll consider it in E minor).
The opening riff, (0:00 in the song), which also serves as the verse riff, is based on power chords on D – E – F with the power chord on E emphasized. This chord pattern, with the F used in lieu of the F#, refers to the Phrygian mode that is commonly used in metal music.
The first unusual tonal shift occurs in the chorus riff (0:31), which includes power chords on E – G – Bb – C#. These notes outline a type of symmetrical scale, meaning that each note is spaced evenly apart (in this case, by a minor third). The presence of the G and Bb could lead one to interpret this chord pattern as suggesting the Locrian scale, which belongs to the family of minor modes. However, the C# does not belong to the minor key at all, referring instead to E major. Hence, even though this chord pattern supports the overall E minor tonality of the song, it also diverges briefly from that tonality with the power chord on C#.
The interlude (1:32) features a melody played with parallel harmonies. The first half of the first riff plays that melody in E minor, and the notes of the melody with the accompanying harmonies combine to include each note of the E minor scale. The second half of the first riff plays that same pattern again, only this time it is transposed down a whole step (i.e. in D minor instead of E minor). This transposition does not constitute a formal change to D minor, nor is it particularly difficult to understand—truly, it is simply a shifting of the riff down two frets on the guitar. Nevertheless, it does impact the tonal fabric of the song by briefly introducing the D minor scale in the E minor context. (note: the below examples rearrange and transpose the notes of the interlude riffs to put them in order and in a more readable position on the staff).
The interlude riff is followed by a variation (1:48) in which the essential melody is retained but one of the harmonic lines shifts to a different set of notes. The result of this shift is that the notes of the melody and the harmonies combine to spell the E Phrygian mode instead (as indicated by the F being used in lieu of the F#). Correspondingly, the second half of the riff is changed to D Phrygian (with an Eb instead of an E). It is a subtle change, and one that works perfectly well within the confines of the overall minor tonality, yet it does present a different flavor.
The bridge (2:15) presents a power chord progression that does not fall so neatly within a modal definition. Over the course of its four measures, the chords involve a descending melodic pattern that is sequenced downward twice. With the chords rearranged from lowest to highest, their tonics spell out nearly all the notes of the chromatic scale (with only an A#/Bb and C#/Db missing). Tonally speaking, we hear the overall E minor key perpetuated in this riff, but clearly the approach is very loose and free form, and the presence of the G# alludes to the E major scale.
The coda of the song (3:26) also fails to strictly conform to the E minor tonality. The first riff features a parallel octave chord pattern that emphasizes E with neighbor motion coming from F and D#. With the F referring to the Phrygian mode and the D# serving as an ordinary leading tone, both notes qualify perfectly fine within E minor. Such is not the case with the following riff, which finds the parallel octave pattern shifted upward to an emphasis on G# with neighbor motion coming from A and G. The note G# belongs to E major, and the prominence of the G# in this riff makes the reference to E major sound more powerfully than it has in earlier moments of the song.
In summary, the overall E minor tonality has either been complimented or challenged by the following aspects:
1. The E Phrygian mode of the intro/verse riff
2. The symmetrical minor 3rd scale of the chorus riff, with the C# referring to E major
3. The momentary shift to a D minor scale in the first interlude riff
4. The E Phrygian mode in the second interlude riff (and corresponding D Phrygian mode in the second half of the riff)
5. The nearly complete chromatic palette of the bridge riff, with G# referring to E major
6. The strong emphasis on G#, referring to E major, in the second riff of the coda
The result is an ever-shifting interpretation of the overall E minor tonality, one that freely weaves in a variety of non-harmonic tones and mixes traditional modes with more innovative and obscure note collections. Many of the nuances, such as the Phrygian moments, are basic and perfectly reasonable within a metal song context. Others, such as the symmetrical scale of the chorus and the pseudo-chromatic collection of the bridge riff, are out of the ordinary and pull in unexpected tones. In addition, the combination of all these changes, slight or significant, put the E minor setting in a constant state of flux.
The subtle manner in which Mastodon make references to E major is particularly noteworthy. At no point do they plainly articulate a formal shift to E major but instead make loose connections that are powerful enough to color the E minor core tonality without completely disrupting it. This is in contrast to many metal band’s (particularly earlier ones) approach to using the major key; it is more usual to find the major key overtly stated and employing that key’s characteristics in a more obvious manner. Mastodon, however, seems to be using modes and keys not by their strict definitions but simply as starting points from which they freely depart and explore uncommon combinations and applications.
In “Blood and Thunder”, Mastodon demonstrates how masterful they are in constructing the tonal fabric of their songs. Many of their other songs exhibit the same characteristics, and examinations of their other works may eventually establish how distinguished Mastodon is from their peers in the treatment of tonality.