VII. Popular Music
Pentatonic Harmony
Mark Gotham and Bryn Hughes
Key Takeaways
- As discussed in the previous chapter:
- Many pop songs use harmonic progressions that imply modes other than major/minor.
- A modal schema may be used without the entire song being strictly within that mode.
- The pentatonic collection is
- a five-note collection
- a subset of the diatonic collection (that’s also explainable in terms of fifths)
- not one of the diantonic modes, because it has fewer notes, but it can be considered alongside them, especially in this context.
- Chord progressions can be understood in terms of the pentatonic based on their bass notes, whether the chords are major, minor or anything else.
- Partly for this reason, it’s common to see the “same” scale degree in more than one form (e.g., mi and me [latex](\hat3, \downarrow\hat3)[/latex])
This book covers modes from many different angles. For more information on modes, check Introduction to Diatonic Modes (general), Chord-Scale Theory (jazz), Diatonic Modes (20th/21st-c.), and Analyzing with Modes, Scales, and Collections (20th-/21st-c.).
Rock music, and popular music more generally, owes a great debt to the blues tradition. One of the most pervasive pitch collections in pop and rock music is the pentatonic collection, a five-note collection also firmly rooted in the blues.
Basic Scale Materials
The pentatonic scale is related to the blues scale and the diatonic scale: it is a subset of both of those collections that is distinctive for containing only 5 pitches and no semitones. As a 5-pitch collection, there are 5 different rotations of the pentatonic collection (just like there are 7 rotations of the diatonic). In this case (unlikely some 5-note collections) all 5 rotations are different from each other.[1] In popular music, the pentatonic scale is typically found in one of two rotations: the “major pentatonic” and the “minor pentatonic” scales. shows these two main rotations (on the top stave) and then all 5 (on the bottom).[2]
“Scale Degree conflict” a.k.a. “Cross Relations”
In rock music, a harmonic system based on the pentatonic scale is typically created by using the scale as chord roots. The chords can be major triads, minor triads, power chords (chords with a root and fifth but no third), or anything else (including sevenths, added notes etc.). Note that this flexibility in terms of the chord “quality” means that the total pitch collection is often not exclusively pentatonic: often, the chord tones combine to make a collection that doesn’t correspond to the pentatonic, or even any of the 7-note modes we’ve encountered so far.
[3] Both staves show major triads built on the notes of the pentatonic scale.
shows how this can be understood in terms of a “conflict” or “cross relation” between scale degrees.- The first collection (upper stave) is built on the pentatonic in “rotation 1” and includes:
- ti and te [latex](\hat7, \downarrow\hat7)[/latex] colored blue);
- The second collection (lower stave) builds on pentatonic “rotation 4”. It includes both
- mi and me [latex](\hat3, \downarrow\hat3)[/latex], colored blue) and also
- la and le [latex](\hat6, \downarrow\hat6)[/latex] (colored purple).
“Scale Degree” / “Cross Relation” conflict through parallel triads
shows major triads on pentatonic scale degrees specifically. This is quite a common example of how cross-relations arise in popular music chord cycles. Nicole Biamonte and others have noted that its probably not a coincidence this fits so well on the guitar: melodies and chord roots based on the pentatonic, with parallel (“barre”) chords that are all major.“Higher Ground” by Stevie Wonder (1973), in which the pervasive harmonic loop can be understood as derived from the pentatonic scale. Note that the while first chord quality is somewhat ambiguous (arguably at least based on parallel major triads with or without added tones), the bass is perfectly clear.
shows an excerpt from
Fifths and Fifth Progressions in light of the Pentatonic
The pentatonic collection is a subset of the diatonic collection and both have the notable property that they can be constructed by successive fifths. For example:
- the diatonic collection can be built from hey succession of fifths like F-C-G-D-A-E-B (in order: C-D-E-F-G-A-B), and
- the pentatonic collection can be formed from the central five of these: C-G-D-A-E (in order: C-D-E-G-A).
That being the case, chord progressions like the cycle of fifths can feature in the pentatonic case, or at least part of that cycle can. Likewise, other chord progressions organised around fifths can be understood in terms of the pentatonic.
For example, successive pairs of fifths a tone apart give progressions like:[5]
- D-A, C-G, …
- G-C, A-D, …
The first of these (D-A-C-G) is the chord progression of TLC’s hit song Waterfalls (1994/5). Once again, we can keep the quality of the chord (major, minor, …) separate from the bass here.
As so often, the distinction between different categories gets complicated. For example, we could also view this view this D-A-C-G progression in terms of Double plagal Mixolydian schema (♭VII–IV–I), but with a V, so I–V–♭VII–IV–(I). So if this progression could be pentatonic and/or mixolydian, what really makes a quintessential pentatonic progression.[6]
Quintessential Pentatonic?
- most of the progressions we’ve seen have fewer than five chords in them (they’re a “subset” of the full collection, whether modal, pentatonic or anything else),
- the quality of those chords and the overall pitch content are quite flexible.
There’s no easy answer – many progressions could be described in terms of either pentatonic or other modes. And that clarity (or otherwise) is related to many factors. For example, if the tonic/final is not clear and we consider only the notes, then all pentatonic progressions are subsets of all diatonic modes because the pentatonic collection is a subset of the diatonic. Usually though we have some sense of the tonic/final and can narrow it down to ambiguities like “minor pentatonic or aeolian subset.”[7] This question (and possible answers) are also related to considerations other than chords: how does the main melody work?, what about any improvised solos?, and (crucially) what is the style/genre context?
Are there any progressions with all five notes of the pentatonic? Why yes, there (occasionally) are. Let’s close by considering an example of a 5-chord pentatonic progression that also draws together many of the topics discussed above.
Hey Joe, where you going with that progression of fourths?
“Hey Joe” has been performed and recorded by countless artists, probably most famously by Jimi Hendrix and the Jimi Hendrix Experience.[8]
The (main) chord progression is a sequence of five chords, with the interval of a descending 4ths (or rising fifth) between each, that ends on the tonic. Hendrix version, 1966). The scale degree conflicts are highlighted as they were above:
shows this progression with a tonic root of E (as is the case in the- mi and me [latex](\hat3, \downarrow\hat3)[/latex], colored blue) and also
- la and le [latex](\hat6, \downarrow\hat6)[/latex] (colored purple).
Biamonte (2010) includes this example, noting the chain of fourths, and seeing this kind of progression in terms of pentatonic mode in rotation 4 (look back to [9]
). Pentatonic rotation 4 seems to be relatively common and it also seems to attract longer chord chains (include 5) than other rotations and contexts do (where 2–4 is typical).In any case, a full 5-chord progression hitting all and only the notes of the pentatonic makes a pretty strong case for a pentatonic reading. But even here, it’s ambiguous. This pentatonic rotation is a subset of several diatonic modes, including the Aeolian (without [latex]\hat2, \hat5[/latex]). And this progression of descending fourths could be heard, once again, in terms of an extended version of the Double plagal – now a “quintuple plagal” perhaps? – which we first encountered in terms of the mixolydian. In that reading, the double plagal (♭VII–IV–I) is now extended as shown on (♭VI–♭III–♭VII–IV–I).
All we can advise is to practice analysing parts separately and combine them freely. In encountering a new piece, you might ask:
- what is the overall tonic?
- what are the chord roots ?
- what is the pitch collection in the chords overall (i.e., not only the roots)?
- what is the pitch collection in the piece overall (i.e., not only the chords)?
Having considered those questions separately, you’re well placed to consider combining them:
- do the chord roots and the overall tonic combine to suggest a mode (whether pentatonic or aeolian, etc.)?
- do the rest of the chord tones fit this or suggest some other origin like parallel writing?
- does the rest of the pitch content fit or not?
- how does all of this relate to other pieces you know and wider questions of style/genre?
Finally, don’t feel the need to come up with categorical, comprehensive answers every time: you can recognise the case for both pentatonic and Aeolian, and view those readings as equal, or come down in favor of one while still recognizing the other.
- Biamonte, Nicole. 2010. “Triadic Modal and Pentatonic Patterns in Rock Music.” Music Theory Spectrum 32 (2): 95–110. https://doi.org/10.1525/mts.2010.32.2.95.
- Lewandowski, Stephan. 2010. »›Fallende Quintanstiege‹. Ein Modellversuch«, Zeitschrift der Gesellschaft für Musiktheorie 7/1, 85–97. https://doi.org/10.31751/508
- Spicer, Mark. 2017. “Fragile, Emergent, and Absent Tonics in Pop and Rock Songs.” Music Theory Online 23 (2). http://mtosmt.org/issues/mto.17.23.2/mto.17.23.2.spicer.html.
- Tagg, Philip. 2011. Everyday Tonality: Towards a Tonal Theory of What Most People Hear. 1.3. New York: The Mass Media Music Scholars’ Press.
- Coming soon!
- See more in the chapter on collections. ↵
- See Biamonte (2010, p.104) for more on the significance of the "minor pentatonic" and the reasons for assigning it as "rotation 1". ↵
- See also this book's chapter on "modal mixture". ↵
- Biamonte further notes that the preference for major quality (and likewise power chords) may be related to the use of "distorted timbres, which render major triads somewhat dissonant, but minor triads significantly more so." (Biamonte 2010, p.104) ↵
- Lewandowski calls these two progressions the fallender Quintanstieg (broadly, falling (progression of) rising fifths, and the steigender Quintfall (rising (progression of) falling fifths). ↵
- Excuse pun! ↵
- For more on distinguishing modes, see the previous chapter. ↵
- "Hey Joe" was the first single released by the Jimi Hendrix Experience in 1966. While the exact origins of this song are not totally clear, it was certainly already a cover song by 1966. It seems that lots of artists are attracted to this song, perhaps partly because of the chord progression discussed here. ↵
- See Biamonte 2010, Ex.22, p.107. ↵
A pitch collection built with the interval pattern ma2–ma2–mi3–ma2–mi3. This collection can also be generated by using scale degrees 1̂, 2̂, 3̂, 5̂, and 6̂ only of the major scale.
A group of pitches being used as the basis for a composition. This term is more neutral than "key," which may imply a hierarchy.
1. A scale, mode, or collection that follows the pattern of whole and half steps W–W–H–W–W–W–H, or any rotation of that pattern.
2. Belonging to the local key (as opposed to "chromatic").