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; rather, 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, 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 have great difficulty making 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 1900 s 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. I propose that we teach blues tonality as a distinct category from major or minor, combining elements of both with elements not found in either. Furthermore, I propose that we present blues tonality as being as fundamental a tonal category as major or minor.
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.
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 is comprised of the intervals minor third, whole step, half step, half step, minor third, whole step. The C blues scale would therefore be the pitches C, E♭, F, F♯, G, and B♭.
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 a less a cleanly defined scale in the usual sense, and more a pedagogical convenience. Whether or not it is a true scale, this collection of pitches is certainly a richly generative one for blues music. For example, the chords built on its roots are strongly ‘bluesy’ when used in combination.
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♭, 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) does not believe there to be 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, he also describes blues melodies as including both major and minor third scale degrees. Sutcliffe also describes a ‘Blues Pentatonic Scale,’ his term for the minor pentatonic scale played over a dominant seventh chord. Intriguingly, he also describes the flattened sixth as “an additional blues 3rd against the major subdominant chord” (n.p.).
Blues practitioners use all of the above scales and more. Nevertheless, I believe that it is both valid and useful to define a singular blues scale, to distinguish it from other scales used in the blues that are already well described using existing standard terminology. It would be less confusing to describe the minor pentatonic scale and the Dorian mode by 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 tonality,’ since 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.
It uses the characteristic minor blues subdominant, ♭VI7, which is comprised “almost exclusively” of the minor 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 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 a great 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 the theme song the 1960s Batman television show both use the twelve-bar scheme, but neither one could be mistaken for blues–they are bluegrass and jazzy rock, respectively. Meanwhile, a great many blues tunes do not use the twelve-bar scheme. 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.
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. Though Franklin retains the gospel elements, 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. In combination with Franklin’s characteristic blues rhythm and pitch play, her melodic inventions bring the song squarely into the blues domain.
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). For example, 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 ‘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). We need not suspect Wagner of harboring any racist sentiments, but her choice of language reveals an implicit cultural bias widespread in the music academy. We can certainly question her judgmental language, and her use of terminology so closely associated with the oppression of ethnic and racial minorities.
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 violating 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 violation of tonal rules, part of a larger practice of willful 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♭ major tonality.
Stoia (2010) joins the above authors in regarding the blues scale as essentially dissonant, in conflict with the underlying diatonic harmony. He acknowledges, however, that this dissonance does not have the same expressive 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, blue notes sound perfectly ‘correct’ and ‘natural.’
Rather than viewing blues as a violation of diatonic norms, we need to understand it as a parallel rule set of norms in its own right. These norms can be surprising for classically-trained musicians. Weisethaunet (2001) points out that in blues, the minor third can sound more correct than the major third over a major chord.
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)!
Hooker’s 1967 recording of “I’m Bad Like Jesse James” is an excellent example of the blending of major and minor that characterizes blues: the piano chords are minor, while the guitar chords are dominant.
Hooker’s song violates Western tonal music’s expectations in another striking way: it never departs from the tonic, E. The song’s blend of major and minor and unresolved tritones sound perfectly correct to blues listeners, the author included. How are we to make sense of this fact?
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, and minor blues is 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 the reverse. He locates blues tonality partially in the practice of substituting a major triad for the tonic chord in diatonic minor or Dorian mode. The chords characteristic of blues can be derived by simply placing a major triad on every root of those modes.
While explaining blues as modal mixture is an ingenious solution, it remains unsatisfying. The surprising quality of modal mixture is predicated on the underlying expectation that major and minor are distinct entities. Blues is not fundamentally in violation of the Western tonal system; rather, it gratifies an alternative set of harmonic expectations.
If the blues scale is a disputed term, the blue note is even more so. We must distinguish between blues scale notes (♭3^, ♯4^, and ♭7^) and blue notes (microtonal pitches that lie between the piano keys.) Non-specialists frequently and incorrectly 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) describe 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 illogically describe the ‘blue third’ as being either minor or as lying between minor and major. To avoid needless confusion, we should reserve the term ‘blue note’ for microtonal pitches.
While I believe the blues scale to be 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 “[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 bent note in the blues–several 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 correctly.
Titon (1977) believes that blue notes should be included 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♭, E, and two distinct intermediate pitches); F; G complex (F#, G and one distinct intermediate pitch); A; B complex (B♭, 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 strictly. In his view, the pitch play that produces blue notes cannot be meaningfully separated from the rest of the musical devices that make up blues feel.
[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).
Perhaps, then, 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.
The chords most characteristic to blues are built on the roots of the blues scale. However, the rest of the chord tones need not derive from the scale the way they would in modal music (Sutcliffe, 2006). The chords associated with the C blues scale are: C7♯9, E♭7, F7, F♯dim7, G7♯9, and B♭7. In Roman numeral terms, that gives us I7♯9, ♭III7, IV7, ♯IVdim7, V7♯9, and ♭VII7. The ♭III and ♭VII chords could also plausibly be defined as major seventh chords. The dominant quality is more ‘bluesy’ to my ears, but an empirical survey of blues music could well show that major sevenths are used more frequently.
There are several diminished chords commonly used in blues tonality aside from ♯IVdim7. A ubiquitous turnaround/embellishment figure uses I7/iii, ♭IIIdim7, IIdim7, I7, or those same chords in the reverse order. Furthermore, the pitches in Idim7 are highly idiomatic to blues melodies. Should these diminished chords be considered fundamental to blues tonality, or are they merely adornments? I do not have a clear answer.
There are two significant differences between blues harmony and diatonic harmony: 1) blues tonality’s ambiguity between major and minor as discussed previously, and 2) the function of tritones, particularly within dominant seventh chords. Both Stoia (2010) and Everett (2004) draw a connection between the flat seventh in blues chords and the flat seventh in the diatonic V7 chord, an ‘embellishment’ that increases the chord’s dissonance and creates an expectation of resolution. 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, dominant seventh chords are not necessarily dissonant or unstable in a blues context. 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.
Blues songs use chord progressions, but the chords do not function in the same way that they do in Western tonal music. Indeed, the dominant V chord is frequently absent, especially in rural blues (Kubik 2005, 207). Country blues musicians’ implicit rejection of the V-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.
Many theorists have tried to understand blues as essentially following the rules of tonal theory. Everett (2004) describes blues as a mixture of 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 argue 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 implausible, especially when one considers the great many blues songs that lack harmonic progression entirely. There is an entire subgenre of so-called ‘primitive’ blues that consist entirely of riffs over a single static chord. John Lee Hooker’s aforementioned “I’m Bad Like Jesse James” is one such song. Another is “Spoonful” by Willie Dixon (1960). Whatever this song’s base tonality is, it is most certainly not major.
Everett’s theory is further weakened by the fact that wildly non-diatonic chord progressions can nevertheless possess strong blues feel. For example, the chords in Charles Mingus’ “Goodbye Pork Pie Hat” (1959) use the entire chromatic scale.
Aside from a continually reasserted tonic, blues harmony need not be functional 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 they may not lead to one another with the inevitability of classical harmonies, they 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 correct over any chord in any tune (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. Perhaps the best way to understand blues harmony will be to conduct a statistical study of chord progressions across a wide corpus of blues recordings.
Blues harmony in context
The diagram below gives one perspective on how blues tonality fits into the larger harmonic universe. Blues can be understood as the union of Western tonal practice and non-Western musics. Following the diagram is an explanation of my terms.
The major scale and its associated harmony, as described by conventional Western tonal theory.
The union of the major and natural minor scales. The term was coined by DeClercq and Temperley (2011) to describe the set of pitches most commonly used in rock and pop melodies.
Non-western modes, drones, and pentatonics
The three broad categories of harmonic practices that Western musicians have incorporated from the rest of the world:
- Modes. Pitch collections that map onto the modes of the diatonic scales, as well as more exotic scales.
- Drones. Tagg (2009) groups blues together with bluegrass, blues-based rock, folk rock, and traditional musics of Africa, the Arab world, Europe and the Indian subcontinent as having non-Euroclassical tonality based on drones. The pedal points ubiquitous in the music of the African diaspora could be considered to be rhythmically broken drones.
- Pentatonics. Almost every world culture uses pentatonic scales. Their widespread use in Western music can be ascribed in part to the ease of playing them on both the piano and guitar.
Major-key music enriched with non-diatonic pitches, like ♯4^ and ♭7^, as is common in jazz practice. Levine (1995) and many other jazz pedagogues describe the ‘bebop major scale’ as the major scale with an added ♭6^. The ‘bebop dominant scale’ is the Mixolydian mode with an added ♮7^. (See also Baker 1988.)
The union of all of the different minor scales commonly used in contemporary music: natural, harmonic, and melodic minor; and Dorian and Phrygian modes. Weisethaunet (2001) observes that contemporary blues players will commonly use the Dorian mode against dominant seventh chords, and that 2^ and 6^ are common additions to the blues scale generally.
The diagram does not attempt to harmonically define or classify all of the world’s music. The bottom circle should really be a complex set of overlapping circles describing many different harmonic practices. Nevertheless, for the present purposes, I felt that the simplification was justified.
Roots of blues tonality
Where do the blues scale and its accompanying tonality originate? We may never have a single unambiguous answer, but there are several plausible theories. Conventional wisdom holds that the rhythms of American vernacular music descend from Africa, while the harmonies descend from Europe. This oversimplification neglects the African-descended harmonic practices persistent in American music that depart widely from European norms.
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 plausible enough, but they do not explain why such minor sonorities came to be used over major chords. Jaffe (2011) moves closer to an explanation by surmising that the blues scale derives from the flatted 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 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 scales, and tuning systems derived from the natural overtone series.
African practice is not the only plausible root for 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 UK folk. 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.
Examples of blues tonality
Jimi Hendrix (1967) – “Purple Haze”
The song is centered around the famous ‘Hendrix chord,’ otherwise known as E7#9. The other two primary chords are G and A7, both with roots from the E blues scale. There are additional chords under the guitar solo, but these are merely a decorative modal backdrop to Hendrix’s blues-based playing.
Parliament (1975) – “P. Funk (Wants To Get Funked Up)”
As is typical of funk music, this song mixes all of the minor scales with the blues scale over a harmonically static background.
Michael Jackson (1979) – “Don’t Stop ‘Til You Get Enough”
The song is largely in B Mixolydian mode, but its keyboard solo uses blues tonality. An even stronger blues connotation comes in the first interval of the vocal melody, 3^ dropping a tritone to ♭7^. Every line of the verses begins with this tritone, and its prominence gives the song a bluesy edge. 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. His most popular albums struggled to reconcile ‘black’ and ‘white’ music (Roberts 2011, 29).
Janet Jackson (1986) – “What Have You Done For Me Lately”
Here is another example of freely mixed major and minor. The line “What have you done for me lately” is minor, and “ooo-ooo-ooo-oooh yeah” is major. The keyboard line that repeats throughout the choruses spells out a diminished chord, a stack of minor thirds that further reinforces the blues feel.
Daft Punk (2001) – “Harder Better Faster Stronger”
The vocoded sung 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.
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.
For the most part, classical music can be characterized by its near-total absence of blues tonality. George Gershwin and James P. Johnson are rare exceptions to this generalization, though it is worth pointing out that both composers are better known for their contributions to jazz.
The most stylistically eclectic musicians will occupy correspondingly larger parts of the tonal Venn diagram. For example, the Beatles’ music touches every section. While most of their music is a blend of diatonicism and blues, they also venture into jazz major in “Sun King” (1969), jazz minor in “Come Together” (1969), Indian-influenced drones in “Within You Without You” (1967), and atonality at the end of “Strawberry Fields Forever” (1967).
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.
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.
Beyond the technicalities of chords and scales, there is a broader social justice argument for treating blues as a fundamental music theory concept. Just as the descendants of the African diaspora have been oppressed and disenfranchised politically, so too has their music been systematically delegitimized by institutional gatekeepers. Western musical culture has warmly embraced the blues and its descendants. Why has the academy not followed suit? The Eurocentrism of most formal music theory curricula is strikingly at odds with the music that most of us listen to and enjoy. There is a lingering vestige of institutionalized white supremacy at work here, one that we as educators should be continually struggling to eradicate. It is time for the music curriculum to catch up to the culture it supposedly describes. It is time for us to place blues harmony at the core of our theory teaching, to match the central place it occupies in the past hundred years of music.
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