The blues is a foundational element of America’s vernacular and art music. It is commonly described as a combination of African rhythms and European harmonies. This characterization is inaccurate. Blues follows harmonic conventions that are quite different from those of European common-practice tonality. Blues does not fit into major or minor tonality, and it makes heavy use of harmonic intervals considered by tonal theory to be dissonant. But blues listeners do not experienced the music as dissonant. Instead, they hear an alternative system of consonance. In order to make sense of this system, we need to understand blues as belonging to its own tonality, distinct from major, minor and modal scales. The author argues that blues tonality should be taught as part of the basic music theory curriculum.
The sound of the blues is heard throughout the world, both directly and via its many stylistic descendants: jazz, R&B, rock, funk, hip-hop, and so on. Given its ubiquity, it is surprising how rarely the blues is addressed by formal music educators. Those scholars and educators who mention the blues at all struggle to make sense of it from a music-theoretic perspective. When approached through a framework of common-practice Western tonal theory, blues is practically nonsensical. Yet blues is widely understood and enjoyed, and it possesses a clear harmonic logic of its own. If music theory claims to explain common practice, it must be able to account for the blues.
The blues emerged in Western culture, and is now a central pillar of it. McClary (2001) observes that while twentieth-century music has no single main stream, it does have a “mighty river” that follows a channel cut by the blues:
When LeRoi Jones published his powerful book Blues People in 1963, his title referred to the African American musicians who fashioned the blues out of their particular historical conditions and experiences. Yet a music scholar of a future time might well look back on the musical landscape of the 1900s and label us all “blues people”: those who inhabited a period dominated by blues and its countless progeny (32-33).
It no longer makes sense to think of the blues, or any other music of the African diaspora, as “non-Western.” Therefore, Western music theory must grow to accommodate the blues, the same way that the music itself has. Rather than seeing the blues as inexplicable, or wildly dissonant, we need to understand its internal logic and how it relates to the broader harmonic universe. This article sets out to explain the characteristic chords and scales of the blues, and argues that they comprise an alternative definition of consonance. It furthermore proposes that we teach blues tonality as a distinct category from major or minor, combining elements of both with elements not found in either.
Defining blues tonality and the blues scale
In order to teach blues tonality, we must first arrive at a precise definition for it. I will argue that blues tonality consists of a scale, the blues scale, accompanied by characteristic microtonal blue notes in between the scale tones. Blues harmony comprises chords whose roots are blues scale notes, but whose other constituent pitches may be drawn from the entire chromatic scale.
There are several scales referred to as “blues scales.” For the purposes of this paper, the blues scale consists of the following intervals: minor third, whole step, half step, half step, minor third, whole step. The C blues scale would therefore be the pitches C, E-flat, F, F-sharp, G, and B-flat.
This is the most commonly used definition both among musicians and scholars, including Levine (1995), Harrison (2001), and Jaffe (2011). However, Jaffe adds the caveat that the “blues scale” is not a cleanly defined scale, but rather a pedagogical convenience, the most prevalent pitches in a larger and more complex set common to blues practice. Whether or not it is a “true” scale, the blues scale as defined above is certainly a richly generative one for creating a sound that registers as blues.
Some authors describe two distinct blues scales, a “major” and “minor” blues scale. Jaffe defines the “Major Blues scale” as the sixth mode of the standard (“minor”) blues scale. The C Major Blues scale would be C, D, E-flat, E, G, and A—the sixth mode of the A blues scale (35).
Greenblatt (2005) uses the same definitions of the minor and major blues scales. Sutcliffe (2006) concurs that there is not a single blues scale. Instead, he understands blues melodies as deriving from the major scale with a flattened third and seventh, i.e., the Dorian mode. However, Sutcliffe also describes blues melodies as including both the major and minor third scale degrees. He further describes a ‘Blues Pentatonic Scale,’ his term for the minor pentatonic scale played over a dominant seventh chord. Intriguingly, he also describes ♭6^ as “an additional blues 3rd against the major subdominant chord” (n.p.).
Blues practitioners use all of the above scales and more. Nevertheless, it is useful to define a singular blues scale, even if it is merely a pedagogical convenience. While there are many scales used in the blues, we do not need a special term for those scales that are already well-described using standard terminology. Rather than referring to the minor pentatonic scale or the Dorian mode as “blues scales,” we should simply use their existing names, and reserve the term “blues scale” for the unique entity described above.
There is less of a need to define a distinct “minor blues scale.” Minor-key blues has merged in modern practice with minor modality generally, to the point of the two being coextensive. John Coltrane’s “Equinox” (1960) is a classic example of minor-key blues.
“Equinox” uses the characteristic minor blues subdominant, ♭VI7, which is comprised “almost exclusively” of the blues scale notes (Jaffe 2011, 37), and can be used in any major or minor-key tune to impart blues feel.
Blues is a tonality, not a song form
If “the blues scale” is a disputed term, “the blues” generally is even more so. Blues as a musical idiom is often equated with the twelve-bar strophic form that shares its name. We must be careful, however, to distinguish between blues tonality and the blues song form. The twelve-bar blues form is what Stoia (2013) describes as a ‘scheme’—a preexisting harmonic ground or melodic structure that forms the basis for the creation of songs. This scheme is neither necessary nor sufficient for defining music as blues. It is the blues’ characteristic harmony that defines it, not any particular song form.
There are many songs using the twelve-bar scheme that do not lie within the blues genre at all. “Shuckin’ The Corn” by Flatt and Scruggs (1957) and Neal Hefti’s theme song to the Batman television show (1966) both use the twelve-bar scheme. However, most listeners would identify the former as bluegrass and the latter as jazzy rock. Meanwhile, it is possible for a song to not use the twelve-bar scheme and nevertheless feel strongly like the blues. Jaffe (2011) cites “Work Song” by Nat Adderley and Oscar Brown Jr. (1960) and “Moanin’” by Bobby Timmons (1958) as blues tunes using alternative song forms. Like all musical genres, the blues lacks crisp boundaries. Nonetheless, blues harmony is a more reliable signifier for “bluesiness” than the twelve-bar form.
It is possible to imbue nearly any piece of music with blues feel by embellishing or replacing its melody notes with blues scale notes. For example, compare Simon and Garfunkel’s original recording of “Bridge Over Troubled Water” (1970) with the version recorded by Aretha Franklin (1971). The song as written is gospel-inflected pop. Franklin retains the gospel elements, but otherwise her interpretation is a wide stylistic departure. She interprets the melody so freely as to essentially rewrite it, replacing its diatonicism with the blues scale throughout. Franklin adds additional blues feel via rhythm and pitch play. The end result is a great deal “bluesier” than Simon and Garfunkel’s version.
Having established that the blues can be identified by its characteristic melodic and harmonic content, we now face the daunting challenge of reconciling blues tonality with the norms of “standard” Western tonal theory. Blues violates several basic rules of common-practice tonality. Should we therefore consider it to be a set of exceptions to those rules, or an different rule set altogether?
Is the blues scale dissonant?
As McClary (2001) observes, “blues musicians privilege a vast palette of sounds that European-trained ears tend to hear as distorted or out of tune” (35). Everett (2004) refers to the tritones and half-steps characteristic of blues as “intrinsically dissonant” (17). Wagner (2003), like Everett, sees the blues as occupying the major-key system, and the blues scale as violating the rules of that system. (Like many authors, she uses the term “blue notes” to refer to blues scale notes, not to the microtonal pitches discussed below.)
Blue notes, by nature, are alienated from their harmonic environment and have a dissonant relationship with them, giving the blues and all its derivatives a rough, angry character. Nevertheless, the hostility of blue notes toward the surrounding world may be mitigated–“domesticated”–through consonantization (353).
Wagner describes blues scale notes as “spoiling” the diatonicism of “clean” chords. By reharmonizing blues scale notes with chords from parallel minor, they become “family” notes that are “at home” in their chords, thus giving them “legitimacy” (354). Reharmonizing a blues scale note “improves” its status because “instead of being an outsider, it becomes a distinguished member of the club” (355). Reharmonized blues scale notes are transformed into “respected members of the community,” although their African roots remain “imprinted on their identity cards” (356). Wagner’s choice of language reveals an implicit assumption, widespread in the music academy, that blues is not native to Western harmony, but rather is foreign, and of lower status.
Tymoczko (2011) echoes Everett and Wagner in his implicit assumption that Western tonality is the “correct” set of rules, and that blues must therefore be in violation of those rules. He understands blues to be an example of the intentional dissonances commonly used in jazz: “polytonality, sidestepping and ‘playing out’” (374). In Tymoczko’s view, blues is the origin of jazz musicians’ willful flouting of tonal rules, part of a larger practice of deliberate asynchrony between melody and underlying harmony.
The origins of [harmonic asynchrony] can perhaps be traced to the blues, which is characterized by ‘blue notes’ that create a delicious dissonance with the underlying harmony… The music thus suggests a kind of polytonality, or clash between independent harmonic streams, in which an upper-register (African-American) ‘blues scale’ contrasts with a lower-register European harmony (374).
Tymoczko immediately follows his discussion of blues with the example of jazz improviser Wayne Marsh playing an E major chord over E-flat major tonality. He is no doubt correct that Marsh is intentionally violating his listeners’ harmonic expectations in order to create tension. However, it is not an accurate analysis of blues practice.
Stoia (2010) joins the above authors in regarding the blues as essentially dissonant, in conflict with its underlying diatonic harmony. He acknowledges, however, that this dissonance does not have the same emotional effect that it does in European-descended music. While blues melodies fall outside of the diatonic system, they do not create the feeling of unease or conflict that they would in a classical context. Stoia uses the term “dissonance” as being coextensive with “notes outside the European tonal system.” However, in a blues context, such “dissonant” notes sound perfectly correct and natural. Weisethaunet (2001) points out that in blues, ♭3^ can sound more correct over a major chord than 3^.
Blues players will also employ the major third in their solos and phrases; however, if this is overdone, it will take the feeling away from that of the blues and make the music sound more ‘jazzy’ or ‘country-like’. From the perspective of the blues performer and listener, the major third against the major chord may thus sound more ‘dissonant’ than the application of the minor third over the major chord (105)!
Blues freely blends major and minor tonality. Hooker’s 1967 recording of “I’m Bad Like Jesse James” is an excellent example: the piano chords contain minor thirds, while the dominant seventh chords in the guitar contain major thirds.
Note that the tritones in the dominant seventh chords never resolve. In fact, Hooker’s song never departs from the tonic chord, E7. The song’s blend of major and minor, its unresolved tritones, and its static harmony all sound perfectly correct to Western blues listeners. How are we to make sense of this fact? We must look outside of common-practice tonality to find our answer.
Is blues really a form of modal mixture?
Since the blues freely combines elements of diatonic major and minor tonality, some authors understand it as a kind of modal mixture. For example, van der Merwe (1992) characterizes blues as a “modality,” not a tonality (118). Turek and McCarthy (2013) see blues as arising from the adding of the flat seventh to diatonic chords:
The lowered seventh present above each root imparts a dominant seventh quality to each chord. The blues and its offspring are the only Western vernacular music in which the Mm7 is routinely divorced from its function as a dominant in need of resolution (584).
By this logic, major blues is merely borrowing elements of parallel minor. Turek and McCarthy regard minor blues to be coextensive with diatonic minor, aside from the addition of #4^, which acts as the only point of harmonic “friction” (594). Tagg (2009) sees blues not as the importing of minor mode materials into major tonality, but rather the reverse. He describes blues tonality as the practice of substituting a major triad for the tonic chord in diatonic minor or Dorian mode.
While explaining blues as modal mixture is an ingenious solution, this rationale is predicated on the underlying expectation that major and minor are inviolably distinct entities. However, “I’m Bad Like Jesse James” defies analysis in this way. Which tonality is the “native” one here, major or minor? Which tonality is being imported in? Hooker treats major and minor as interchangeable. Blues is not in violation of or an exception to the Western tonal system; rather, it gratifies an alternative set of harmonic expectations. Our ears have been conditioned by the blues to hear the breakdown of the major/minor binary as unremarkable. That is why a pop song like Janet Jackson’s “What Have You Done For Me Lately” (1986) can freely mix major and minor without putting off mainstream listeners. In the chorus, the line “What have you done for me lately” is minor, and “ooo-ooo-ooo-oooh yeah” is major. Neither sounds like it is “borrowed” from a parallel modality; they sound like they belong together within blues harmony.
If the blues scale is a disputed term, the “blue note” is even more so. We must distinguish blues scale notes (♭3^, ♯4^, and ♭7^) from blue notes (microtonal pitches that lie between the piano keys.) As mentioned above, theorists and practitioners alike frequently refer to ♭3^ and ♭7^ (and sometimes ♯4^) as blue notes. Quite a few theorists use the term “blue notes” both for microtonal and piano-key notes. For example, Turek and McCarthy (2013) define blue notes both as the equal-tempered ♭3^ and ♭7^, and, later, as “pitches, most notably the third and seventh scale degrees, slightly flatter than their equal-tempered counterparts” (593). Stoia (2013) is one of several theorists who describe the “blue third” both as being minor, and as lying between minor and major. These contradictory usages are needlessly confusing. We can impose some clarity by reserving the term “blue note” exclusively for microtonal pitches.
While the blues scale is consonant within the context of blues tonality, the blue notes do create the feeling of tension and instability that we usually ascribe to dissonance: “So close is the parallel that it is not misleading to use the term ‘melodic dissonance’” (van der Merwe 1992, 120). Blues musicians treat pitches “as mobile, unstable units instead of treating them as discrete points in a scale” (Tallmadge 1984, 155). Should we consider blue notes to be stable units, of equal significance to the blues scale itself? Or are they best thought of as embellishments, the consequences of blues musicians’ pitch play?
The most commonly referred-to microtonal blue note in the literature is the “neutral” third, the pitch lying mid-way between ♭3^ and 3^. Van der Merwe (1992) asserts boldly that, in blues practice, “[i]nstead of the major and minor thirds of the printed page, most of the thirds will be neutral in actual performance” (123). Furthermore, he observes that the third is not the only microtonal note in common blues usage. Several other pitches can be flattened by a quarter tone or a full semitone: “The degrees of the mode treated in this way are, in order of frequency, the third, seventh, fifth, and sixth” (119). These are empirical statements that might or might not be substantiated through analysis of recordings, but van der Merwe does at least categorize the blue notes consistently as microtones.
Titon (1977) believes that blue notes should be included in the basic definition of the blues scale. Using a corpus of recordings of “downhome” or country blues made between 1926 and 1930, Titon identifies the set of the most commonly occurring pitches as the “downhome blues scale” (155). The downhome blues scale in C consists of the following pitches: C; D; “E complex” (E-flat, E, and two distinct intermediate pitches); F; “G complex” (F-sharp, G, and one distinct intermediate pitch); A; “B complex” (B-flat, B, and one distinct intermediate pitch); C’; D’; and E’ complex. Titon maintains that the scale should span a tenth rather than an octave, because the blues musicians in his study treat the lower octave differently than the higher one. He identifies this practice as the basis for the bluesy sound of the 7#9 chord, with ^3 in the lower octave and ♭3^ on top. Titon also tallies the most frequent movements from one blues scale pitch to another within his corpus, and proposes a generative system for blues melodies by cataloging melodic contours derived from them.
Weisethaunet (2001) sees blue notes as a central component of blues tonality, but is reluctant to define them so strictly. In his view, blue notes are a consequence of performers’ pitch play. Rather than viewing them as distinct entities, Weisethaunet argues that we should understand blue notes to be inseparable from the other expressive devices comprising the feel of the blues.
[I]n blues performance every note may be bent or altered, but in different ways depending on style and how such notes appear in the harmonic texture. One of the most frequently heard ‘blue notes’ as regards pitch discrepancy in post-war electric guitar playing may be that of the bent fourth: this is commonly bent to include different pitches between the fourth and the fifth (and higher pitches as well). The second (which does not even appear in what scholars have named the blues scale) also seems to be a very common ‘blue note’ feature of most blues guitarists’ repertoires: moving between the second and the minor third in innumerable ways. In fact every note of the twelve-tone chromatic scale may appear in a blues tune, possibly also as ‘blue notes’, because microtonality, attack, and timbre variation are such essential parts of blues expression (Weisethaunet 2001, 101).
Is Titon correct that there is a finite number of blue notes that can be formalized into a scale, or should we be convinced by Weisethaunet that the entire pitch continuum is available to blues musicians, making it impossible to define a discrete set of blue notes? For the sake of pedagogical clarity, perhaps we should take the view that the blues scale is more than a straightforward set of equal-tempered piano-key notes; rather, that it is a group of islands in the midst of the pitch continuum, home bases from which to explore the surrounding microtones. This issue requires considerable further study.
We can treat the blues scale as the roots of a set of accompanying chords, the same way we do with diatonic scales and modes. Unlike diatonic scales and modes, however, the chords built from the blues scale need not be comprised solely of pitches found within the scale (Sutcliffe 2006). The chords associated with the C blues scale are: C7♯9, E♭maj7, F7, F♯dim7, G7♯9, and B♭7. In Roman numeral notation, that gives us I7♯9, ♭IIImaj7, IV7, ♯IVdim7, V7♯9, and ♭VII7. (The ♭VII chord could also plausibly be defined as a major seventh chord.)
There are several diminished chords commonly used in blues tonality aside from ♯IVdim7. A ubiquitous turnaround/embellishment figure uses I7/iii, ♭IIIdim7, IIdim7, and I7, or those same chords in the reverse order. Furthermore, the pitches in Idim7 are highly idiomatic to blues melodies. In Janet Jackson’s “What Have You Done For Me Lately” (1986), the keyboard line that repeats throughout the choruses uses a diminished arpeggio that lends blues feel to the track’s glossy pop sound.
Should we consider Idim7 and IIdim7 to be as fundamental to blues tonality as ♯IVdim7, or are they merely adornments? There is no clear consensus among theorists or practitioners.
The blues treats dominant seventh chords in a strikingly different way than common-practice tonal harmony. In the blues, dominant sevenths can be tonic chords, destinations for harmonic closure. The V7/I cadence also appears in blues. Did the blues I7 and IV7 derive from the common-practice V7? Both Stoia (2010) and Everett (2004) think so. Stoia in particular bolsters his case by citing the frequently-used blues device of treating I7 as V7/IV in anticipation of the fifth bar of a twelve-bar blues form. However, we cannot understand every dominant chord in the blues to be cadential. Blues songs routinely begin and end on I7, with a feeling of resolution that is as satisfying as a perfect authentic cadence is in classical music. Should the I7 chord’s tritone be considered dissonant or unstable in this context?
Let us consider Michael Jackson’s “Don’t Stop ‘Til You Get Enough” (1979). The song is largely in B Mixolydian mode, and the very first interval of the vocal melody is 3^ dropping a tritone to ♭7^. Each line of the verses begins with this tritone, and it never “resolves.” The tritone’s prominence gives the song a bluesy edge, reinforced by the blues scale used in the keyboard solo.
Questions of genre in popular music are densely intertwined with questions of racial identity. In 1979, Michael Jackson was beginning the process of bridging the racial divide in American pop, a process that would culminate in the unprecedented crossover success of Thriller (1982). His most popular albums struggled to reconcile “black” and “white” music (Roberts 2011, 29). We can hear that struggle manifest in his fusion of blues tonality with more anodyne modal and diatonic harmonies.
Most blues songs use chord progressions, but the chords do not function in the same way that they do in Western tonal music. The V7 chord is frequently absent, especially in rural blues (Kubik 2005, 207). Country blues musicians’ implicit rejection of the V7-I cadence was made explicit by bebop musicians in the 1940s. While their source material of Tin Pan Alley songs was full of cadences, musicians like Charlie Parker and Dizzy Gillespie disguised and obscured those cadences by means of tritone substitutions and other reharmonization techniques. Later jazz musicians abandoned the harmonic skeletons of standards entirely in favor of modes, atonality, and exotic scales. Indeed, the sole consistent thread through all jazz styles is the blues.
Even though so many blues songs eschew V7-I cadences, some theorists continue to insist that blues harmony fundamentally adheres to the norms of Euroclassical tonality. One such theorist is Everett (2004), who describes blues as minor pentatonic melodies lying atop functional diatonic harmony.
[T]he blues has an essentially major-mode structure. In the twelve-bar-based “School Days,” Chuck Berry’s vocal and lead guitar parts are thoroughly pentatonic, but the structure-expressing bass and piano boogie in the major mode. The rarity of exceptions, as found in B. B. King’s minor-mode “The Thrill is Gone,” proves the rule. If this seems out of line with prevailing descriptions, which typically rely on reference to a “blues scale” and don’t seem to discriminate between tonal characteristics of melody and backing, consider the rhythm section’s accompaniment aside from all vocal and solo melodic lines. It is in the supportive major-mode instrumental chordal backing, not in the soloistic melodic material, that structural harmony is expressed ().
Everett acknowledges that not all blues songs use structural dominants, which poses a problem for his analysis. His solution is to propose that even when the V7 is absent in blues, it is nevertheless implicit because “it is of structural value in the major system that is inhabited by that blues” (). This seems like a stretch. When we listen to a song like “Spoonful” by Willie Dixon (1960), which consists entirely of minor riffs over a single static dominant chord, are we really supposed to imagine that functional major harmony is hidden somewhere underneath?
Everett’s theory is further weakened by the fact that wildly non-diatonic chord progressions can nevertheless possess blues feel. For example, the chords in Charles Mingus’ “Goodbye Pork Pie Hat” (1959) are drawn from the entire chromatic scale, but it nevertheless registers as strongly “bluesy.”
Aside from a frequently reasserted tonic, the chords in blues need not follow any functional rules at all.
In blues harmonic practice, unresolved tritones can appear over any root, sometimes generating an impetus for motion and sometimes not. A one-chord blues can be based on a seventh chord over a repeating bass figure, and can easily accommodate extensions beyond the seventh. The addition of the sharp ninth merely adds colour to the tonic in this case, rather than a tension requiring resolution (van der Bliek 2007, 346).
Blues chord progressions may not be “functional,” but they are assuredly not random either. While the chords may not lead to one another with the inevitability of classical harmonies, blues chords are more satisfying in some combinations and sequences than others. The issue of functionality within blues harmony is complicated by the fact that, unlike any other scale in common Western use, the blues scale is a kind of “universal harmonic solvent.” It sounds reasonably correct over any chord in any tune in any American vernacular style (Levine 1995, 230). While the combination of the scale against the chords in a typical blues or pop song produces a great deal of dissonance, in the blues context the dissonance is perfectly acceptable. The clash of adjacent chromatic pitches in blues sounds right, not wrong. We will need a new and broader concept of chord/scale function in order to make sense of blues harmony.
Roots of blues tonality
Blues tonality is a set of harmonic practices distinct from those of Western common-practice tonality. Having made some steps toward understanding what specifically those harmonic practices are, we can now turn our attention to the question of blues tonality’s origins. It is a truism that the blues is a fusion of African rhythms with European harmonies. While this is true to an extent, the previous sections detail the many ways that blues tonality differs from classical practice. So where did blues tonality come from? We may never have a single unambiguous answer, but there are several plausible theories.
Tagg (2009) is one of many authors who explain the blues scale as an extension of the minor pentatonic scale. Harrison (2001) posits that the blues scale descends from the minor pentatonic scale by adding a chromatic “connector” between 4^ and 5^ (35). These theories are reasonable enough, but they do not explain why such minor sonorities came to be used over major chords in the first place. Jaffe (2011) moves closer to an explanation by surmising that the blues scale emerged from the practice of flatting the diatonic 3^, 5^ and 7^—in blues, these pitches can either replace or coexist with their diatonic counterparts. Characteristic jazz sonorities like 7#9 would then emerge out of superimposition of the flatted diatonic scale notes onto the diatonic I, IV and V chords (37).
A more complex explanation of the blues scale can be found in van der Merwe’s concept of the African-descended “ladder of thirds” (1992). By this theory, the blues scale originated by stacking minor thirds above and below a central pitch. Adding a minor third to the tonic gives the blues scale’s ♭3^, and adding another minor third gives #4^. Adding a minor third on top of the major triad gives the blues scale’s ♭7^. Van der Merwe supports his theory with the observation that in blues, the minor third interval has a similar function to the leading tone in Western tonal theory. In blues melodies, ♭3^ can be heard as resolving down to tonic, and 6^ can resolve up to tonic.
Kubik (2005) has observed that listeners to certain field recordings from various regions in Africa find them to be particularly “bluesy,” and that those recordings share particular musical properties.
I discovered that in many cases, the impression was created by just a few traits that appeared in those musical styles in various combinations and configurations: (a) music with an ever-present drone (bourdon), (b) intervals that included minor thirds and semitones, (c) a sorrowful, wailing song style, and (d) ornamental intonation. Songs with a prominent minor seventh in a pentato hexatonic framework also sometimes received this designation, as did pieces that featured instrumental play with a clash between a major and minor third or with a specific vocal style (191-192).
Kubik therefore sees blues and jazz as the effort of black musicians to recreate African tonal practice on instruments designed for European scales. Specifically, the African practices he believes to have led to the blues include the “span” process (a kind of harmonic parallelism), the use of equiheptatonic tunings and scales, and tuning systems derived from the natural overtone series.
African practices are not the only plausible roots of the blues scale. Various European folk musics, particularly those of the United Kingdom, use thirds lying between the equal-tempered minor and major thirds. The “ladder of thirds” is also common to British folk music. It is quite possible that the myriad African musical practices imported to the United States by the slave trade became established due to the “catalytic influence” of British folk styles over the course of the 19th century (van der Merwe 1992, 145). Given the hybrid nature of all other American music, we should expect nothing different for the history of blues tonality.
Blues tonality and genre
Nearly all American popular and vernacular is informed by blues. We can use this fact to help delineate overlapping and vaguely defined genre boundaries. For example, how do we decide that a song is rock, or folk, or country, or country-rock, or folk-rock? Just as we can explain genre in terms of characteristic rhythms and timbres, so too can we explain it in terms of the amount of blues harmony present. Pop and jazz practitioners already do this implicitly–whether through intuition or systematic practice, they must understand how much blues tonality to use in order to sound more characteristically “jazzy” or “country” or “rock.”
Let us use the example of funk. Aficionados know when music is funky, but what on what basis do we make that determination? We can point to the rhythms, but funk shares those with disco, hip-hop, R&B, and some rock. We can define funk more specifically by examining its harmonic content. Like rock, funk is heavily blues-based. Unlike rock, however, funk uses little diatonicism and a great deal of jazz harmony.
Using the blues harmony framework, it is possible to look at two stylistically similar songs and understand why one is funkier than the other. For example, “Jungle Boogie” by Kool and the Gang (1973) is funkier than “Inside and Out” by the Bee Gees (1979). The difference is not in the songs’ respective rhythms; both have impeccably funky grooves. The difference is harmonic. “Jungle Boogie” has no chord changes, and its melodic components are comprised entirely of blues tonality, embellished with some jazz-inflected chromaticism. “Inside and Out” has a similar jazz/blues feel in its verses. However, its prechorus, chorus and bridge are either modal or diatonic. The Bee Gees’ less bluesy harmony combines with their their smoother and more polished timbres to pushes their music from funk firmly into disco.
We can also use harmony to better define country music. While country uses its share of blues harmony, it is largely diatonic, and it rarely if ever introduces jazz harmony. It is instructive to look at the example of “Lovesick Blues” by Hank Williams (1949). Its title notwithstanding, the song is not blues per se; indeed, it is as straight a country song as one could ask for. The harmony consists entirely of diatonic tonality that would not sound out of place in Mozart. The “blues” in the title mostly refers to the song’s melancholy tone, though we can also also detect blues inflection in Williams’ flattened thirds.
Blues tonality and rock
Rock harmony is mostly diatonic, but it features some characteristic deviations from the conventions of tonal harmony as well. These deviations are due to the influence of the blues. This influence is pervasive; a great many rock songs are simply the blues played faster and louder. The first rock song to top Billboard magazine’s main sales and airplay chart, “Rock Around the Clock” by Bill Haley and the Comets (1955), is a straightforward twelve-bar blues (Browne 2001, 358). The blues influence was felt especially strongly by British rock musicians in the 1960s, and they in turn spread awareness of blues to mainstream white American listeners (Schwartz 2007, 22).
Beyond direct borrowing and imitation, how might we gauge the impact of blues on rock? One invaluable resource is DeClercq and Temperley’s corpus analysis of rock harmony (2011). The authors analyze the twenty top-ranked songs from each decade of Rolling Stone magazine’s list of the ‘500 Greatest Songs of All Time’. The Rolling Stone corpus uses a broad stylistic definition of ‘rock’—so broad, indeed, that it includes an assortment of non-rock songs, including representatives from jazz, country, pop, R&B and hip-hop.
The most immediate difference between common-practice harmony and rock harmony as represented by the Rolling Stone corpus is the high incidence of both the ♭7^ scale degree and the♭VII chord. These are rare in common-practice minor tonality, and vanishingly rare in common-practice major tonality (DeClerq & Temperley 2009). While the flat seventh probably entered rock through a number of vectors, like the Mixolydian mode used in various folk musics, blues is likely the main source.
Rock’s other major departure from common-practice tonality lies in the distribution of pre-tonic and post-tonic chords. In rock, the most common chord preceding the tonic is IV, whereas in common-practice music it is V. Furthermore, in rock, the IV, V and ♭VII chords are as likely to precede the tonic in rock as to follow it. Again, rock has many streams of influence, and any number of folk musics have contributed to the relaxation of the rule that V must precede I. Once again, however, blues is likely to have played the strongest role.
Blues tonality is not widely discussed in rock theory, but its presence is often implicit. For example, van der Bliek (2007) describes the dominant seventh sharp nine chord, nicknamed the ‘Hendrix chord,’ as adding a “blues tonal element” (344). The Hendrix chord is built around a set of pitches that represent “a significant portion of the tonal markers of melodic activity in the blues idiom” (van der Bliek 2007, 345).
If there is a single element unifying all forms of Western popular music, it is the loop structure, as opposed to the linear narrative structure of classical music. The static, loop-based harmonic nature of blues is likely a major influence in this regard. Tagg (2009) observes that chord loops in blues-descended pop create a sense of states, conditions, or ‘places to be’, rather than acting as components of a large-scale tonal scheme.
All of the above points notwithstanding, Everett (2004) would have us believe that blues tonality is not a significant component of rock.
There may be such a thing as a blues scale (with or without a lowered fifth scale degree)… but this has nothing to do with rock music, which borrows only from a blues that colors a structural major mode with minor-pentatonic melodic borrowings.
The blues scale may not be a typical feature of rock vocal melodies, but it is the bedrock of rock guitar solos. Indeed, a great many lead guitarists do not know any other scales. A central stylistic difference between a jazz soloist and a rock soloist is that the jazz soloist will generally follow the chord progression, whereas the rock soloist will stick to a single pentatonic or blues scale regardless of the underlying harmony. A typical case in point is “Ophelia” by The Band (1975). The song has a richly functional ragtime-style chord progression full of secondary dominants. However, lead guitarist Robbie Robertson does not follow the changes at all; he simply plays the blues scale over the entire form.
The natural synergy between the blues and the guitar is partially due to an accident of ergonomics: the pentatonic and blues scales are easier to visualize and play on the fretboard than the diatonic scales. Informally trained guitarists typically learn the pentatonic scales first, and then add pitches to them to form additional scales. This approach is not unique to guitarists. Greenblatt (2005) presents a similar method aimed at improvising horn players. His text begins with major and minor blues, and then adds additional pitches to round out fuller diatonic and modal harmonies. Music educators in general might do well to place the blues front and center in their theory pedagogy, since it act as an effective scaffold for the learning of any other Western harmony.
Suggestions for future research
It is challenging at best to pin down American music by genre. The boundaries between rock, folk, country, jazz, R&B, funk, and many other styles overlap and even blur away completely. Blues tonality can be an invaluable tool to help us delineate genres. For example, funk and disco share characteristic rhythms, but funk uses more blues tonality, while disco uses more diatonic and modal tonalities. Country music contains more blues tonality than folk, and rock contains more blues tonality than country. We might even use the presence of blues tonality as a way to make the nebulous concept of “soul” more concrete.
Reasonable people can disagree as to which chords and scale tones are distinct to the blues, and which are modal or pentatonic. We may never be able to settle such questions without a broad empirical study of a wide corpus of blues recordings, as Titon did with country blues. However, we face the difficulty of defining such a corpus in the first place, because we cannot do so without first defining what the blues is, leading us to a tautology. It would be worth investigating the means by which large music information retrieval systems categorize blues for the purposes and automated recommendation.
There is considerable controversy as to whether there is such a thing as the “blues scale” at all. Should we say that the blues scale(s) consist(s) of all the pitches used in the blues? That leaves us with the entire chromatic scale plus many pitches in between, which is such a broad category as to be useless. Do we understand the blues scale to be the set of points on the pitch continuum that are frequently, but not exclusively, visited by blues practitioners? One can play blues perfectly well on equal-tempered piano; does that mean that microtones are an optional embellishment, or is the piano insufficient for full blues expressiveness?
This paper does not address the role of rhythm in determining “bluesiness.” This omission is deliberate, in order to give clearer focus to the analysis of blues melody and harmony. Nevertheless, rhythm is extremely important to understanding the blues, and blues harmony nearly always goes hand-in-hand with syncopation and swing. An interesting example from well outside the blues genre is “Harder Better Faster Stronger” by Daft Punk (2001). The vocal melody uses diatonic minor for the beginning of the song. Starting at 2:30, however, the tonality switches to blues, accompanied by a funkier and more syncopated rhythmic feel.
Can blues tonality be considered independently of rhythm? Or are the two inseparable? This is fertile soil for future research.
We use the term “common-practice tonal theory” for a curriculum that does not address actual Western common practice. The musical traditions of the African diaspora are as fundamental to our culture as those of Europe. African diasporic musical culture expresses itself through all of America’s indigenous music: jazz, rock, hip-hop, R&B, country, and of course, the blues. The music academy gathers all of these genres together under the term “popular music” (with the exception of jazz, which in recent decades has become a “legitimate” art music.) Feld (1988) goes so far as to describe American popular music as “a euphemism for Afro-American popular musics” (31). American popular music has touched every corner of global culture. We do music students a grave disservice if we send them out into the world ignorant of the blues.
Popular musicians, who tend to be self-taught, already effectively treat blues as a core concept, a chord-scale system on an equal footing with common-practice tonality (Green 2002, 43). Some jazz theorists do as well. Jaffe (2011) divides harmony into three distinct tonal systems: diatonic harmony as described by tonal theory, modal harmony, and blues. Given how pervasive the influence of jazz and rock are in all other Western music, the music academy at large should address blues as part of standard theory pedagogy. In order to do so, we must arrive at a consensus as to what blues tonality consists of. This paper represents a step in that direction; hopefully, it will become one among many.
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