Blues tonality

See a more beginner-friendly blues primer here. Read this treatise in Spanish, translated by Jesús Fernández.

Abstract

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 description is inaccurate. Blues follows harmonic conventions that are quite different from those of Western European common practice. Blues harmony does not fit into major or minor tonality, and it frequently violates the “rules” of voice leading and chord function. But blues listeners do not experience the music as strange or dissonant. Instead, they hear an alternative form of consonance. In order to make sense of this fact, we need to understand blues as belonging to its own system of tonality, distinct from major, minor and modal systems. Because blues tonality is so widespread and important in Western music, I argue that we should teach it as part of the basic music theory curriculum.

Introduction

The sound of the blues is heard throughout the world, both directly and via its many stylistic descendants: jazz, R&B, country, rock, funk, hip-hop, and so on. Given its ubiquity, it is surprising how rarely the blues is addressed in formal music theory pedagogy. When theory books and curricula mention the blues at all, they struggle to make sense of it. Blues violates many of the norms of common-practice Western tonal theory. Yet blues is widely understood and enjoyed, and it possesses a clear harmonic logic of its own. If music theory pedagogy claims to explain Western “common practice”, then it must be able to account for the blues.

The blues first emerged in the United States, and it has since grown to be a central pillar of Western musical culture. Susan McClary (2000) observes that while twentieth-century Western music has no single main stream, it does have a “mighty river” following 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… 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 (pp. 32-33).

If your only knowledge of Western music came from typical university music theory curricula, however, you might never guess that the blues even existed, much less get a sense of its importance. Theory pedagogy must grow to accommodate the blues, the same way that our culture has.

In this treatise, I set out to explain the characteristic chords and scales of the blues, and I argue that they comprise an alternative system of tonality from European common-practice tonality. I further propose that we teach blues tonality as a distinct category from major or minor, combining elements of both with elements not found in either. Andy Jaffe (2011) divides Western harmony into three distinct systems: diatonic harmony as described by tonal theory, modal harmony, and blues. I believe that mainstream Western music theory pedagogy should adopt this classification scheme, and present the three systems as equally fundamental. Popular musicians, who tend to be self-taught, already consider blues to be a core concept, a chord-scale system on an equal footing with common-practice tonality (Green, 2002, p. 43). For example, like many rock guitarists, I learned the pentatonic and blues scales long before I learned the major scale.

Before we can understand and teach blues tonality, we need to define what we are talking about. I will argue that blues tonality consists of a scale, the blues scale, accompanied by microtonal blue notes. Blues harmony comprises chords whose roots are blues scale notes. In this treatise, I have deliberately chosen to only touch lightly on the rhythmic, timbral and formal aspects of blues. These aspects of the music are critically important. I have chosen to focus only on blues harmony because it is so conspicuously absent from harmonic theory and pedagogy.

The Blues Scale

There are several scales referred to as “blues scales.” I first learned the blues scale as consisting 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 scale first appeared in print in Jamey Aebersold’s 1967 book How to Play Jazz & Improvise. It has since been referenced by many blues musicians, teachers and scholars, including Mark Levine (1995), Mark Harrison (2001), and Andy Jaffe (2011). There is considerable controversy as to whether or not the Aebersold scale is a “real” scale.  This ambivalence reflects the broader unease that the jazz community feels about the institutionalization of Black American music in general (Chodos, 2018). Jaffe argues that the Aebersold scale is not a scale in the conventional sense, but rather, a pedagogical convenience, the most prevalent pitches in a larger and more complex set common to blues practice.

Some authors describe two distinct blues scales, a “major” and “minor” blues scale. Jaffe (2011, p. 35) and Dan Greenblatt (2005) define the “Major Blues scale” as the second mode of the standard (“minor”) blues scale. The C major blues scale would therefore be the pitches C, D, E-flat, E, G, and A—the second mode of the A minor blues scale.

There are several other pitch collections that have been called “blues scales.” For example, Bruce Benward and Marilyn Saker (2009) define the blues scale as “a chromatic variant of the major scale with a flat third and flat seventh” (p. 43), i.e., Dorian mode. It is noteworthy that Benward and Saker list the blues scale in a list of esoteric and non-Western scales; it appears in their text immediately after the whole tone scale and immediately before Todi, a northern Indian mode. This tendency to present the blues as esoteric or exotic is a troubling form of exnomination.

Tom Sutcliffe (2006) also defines the blues scale as Dorian mode used over a major tonality background. 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. Finally, Sutcliffe describes ♭6^ as “an additional blues 3rd against the major subdominant chord” (n.p.). I have not seen this intriguing idea described elsewhere.

Gunther Schuller (1968, pp. 43-44) cites Winthrop Sargeant’s idea that the blues scale consists of two identical tetrachords, one surrounding the tonic, the other surrounding the fifth. These tetrachords include the pitches a minor third below, and a whole step and minor third above the central note. In C, that gives A, C, D and E-flat around the tonic, and E, G, A and B-flat around the fifth. If we combine the two tetrachords, we get the following scale: C, D, E-flat, E, G, A, B-flat. This is Jaffe’s major blues scale with an added flat seventh, or Dorian mode with the major third replacing the fourth. John Fahey’s (2020) study of Charley Patton similarly identifies two main “blues modes”: the union of Dorian and Mixolydian modes, and Mixolydian mode itself. Gerhard Kubik (2008, pp. 176-177) lends credence to Fahey’s first blues mode by positing an origin for blues tonality in the lower and middle overtones of scale degrees 1^ and 4^, a set of pitches whose closest equal-tempered equivalents is the union of Dorian and Mixolydian.

George Russell (2001) proposes two blues scales, the “Auxiliary Diminished Blues Scale” and the “African American Blues Scale”. The Auxiliary Diminished Blues Scale is the same pitches as the half-whole diminished scale. While this would be an unusual scale to play in a traditional context, it does include the tonic diminished chord that is a common feature of the blues. Russell’s African American Blues Scale is the same pitches as Lydian dominant mode with an added natural seventh.

Blues practitioners use all of the above scales and more. Nevertheless, I believe that it is useful to define the Aebersold scale as “the blues scale.” Whether or not it is a “real” scale, it is a useful and distinct set of pitches for creating a recognizably bluesy sound. While there are many other scales used in the blues, it is not necessary to use a special term for the ones that have widely used names. Rather than referring to the minor pentatonic scale or the Dorian mode as “blues scales,” I believe that it would be more clear to simply use their existing standard names, and reserve the term “blues scale” for the Aebersold scale.

Blue Notes

If the blues scale is a disputed term, the “blue note” is even more so. Numerous authors use the term to describe both blues scale notes (♭3^, ♯4^, and ♭7^) and microtonal pitches that lie between the notes in the equal-tempered chromatic scale. For example, Ralph Turek and Daniel 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” (p. 593). Nicholas 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 eliminate confusion by reserving the term “blue note” exclusively for pitches outside of twelve-tone equal temperament (12-TET).

Gerhard Kubik (2008) believes that blue notes are not an alteration of equal tempered pitches, but rather, the reverse: the equal-tempered blues scale pitches are compromised versions of the original pitch set of the blues. Kubik locates the origin of blues tonality in the overtone series of scale degrees 1^ and 4^. Some of these pitches can only be approximated within 12-TET, but they can be played correctly on instruments with finer pitch control: guitar (especially with slide), violin, trombone, fretless banjo, and of course, the voice. By Kubik’s theory, when blues musicians bend notes, they are not trying to make them go out of tune; instead, they are playing them more in tune. This theory aligns with my intuitive experience as a player.

The most commonly referred-to microtonal blue note is the “neutral” third, a pitch lying between ♭3^ and 3^. Peter 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” (p. 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” (p. 119). These are empirical statements that might or might not be substantiated through corpus analysis of recordings, but van der Merwe does at least categorize the blue notes consistently as microtones.

Jeff 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” (p. 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. Court Cutting’s (2018) digital analysis of vocal pitches from fifteen classic early blues recordings aligns with Titon’s findings, identifying three main blue note clusters: the neutral third, a collection of pitches between 4^ and ♯4^, and a collection of pitches surrounding around ♭ 7^.

Hans Weisethaunet (2001, p. 101) sees blue notes as a central component of blues tonality, but he is reluctant to define them strictly. In his view, blue notes are a consequence of performers’ expressive pitch play. Rather than viewing them as distinct entities, Weisethaunet argues that we should understand blue notes to be inseparable from performers’ rhythmic and timbral embellishments. William Tallmadge (1984) agrees that blues musicians treat pitches “as mobile, unstable units instead of treating them as discrete points in a scale” (p. 155). In my own listening and performing experience, any chromatic pitch can be microtonally embellished in the blues.

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 and Tallmadge that the entire pitch continuum is available to blues musicians, making it impossible to define a discrete set of blue notes? Perhaps we should take the view that the blues scale is more than a straightforward set of equal-tempered piano-key notes; instead, that it is a group of islands in the midst of the pitch continuum, home bases from which to explore the surrounding microtones. Alternatively, we might follow the recommendation of Jeff Titon and Panos Charalampidis’ YouTube channel and see blue notes as pitch zones rather than single points. This issue requires considerable further study.

Blues Harmony

We can treat the Aebersold 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 will 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♯°7, G7♯9, and B♭7. In Roman numeral notation, that gives us I7♯9, ♭IIImaj7, IV7, ♯IV°7, 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 in addition to ♯IV°7. A ubiquitous turnaround/embellishment figure uses I7, ii7, ♯ii°7, I7, or those same chords in the reverse order.

The pitches in I°7 are highly idiomatic to blues melodies. Robert Johnson alternates between I7 and I°7 in several of his songs, including “Kind Hearted Woman Blues.” The tonic diminished chord is a fascinatingly bluesy one. It includes three of the four pitches in IV7, and all of its pitches are in the blues scale or major blues scale. Should we consider I°7 and ♯ii°7 to be as fundamental to blues tonality as ♯IVdim7, or are they merely adornments, the equivalent of chromatic passing chords in classical music? There is no clear consensus among theorists or practitioners.

There is one other characteristic blues chord, the minor blues subdominant, ♭VI7 (A♭7 in the key of C.) While its root is not in the blues scale, this chord is otherwise comprised entirely of blues scale notes (Jaffe, 2011, p. 37). The ♭VI7 chord can be used in any major or minor-key tune to impart blues feel. John Coltrane’s “Equinox” (1960) is an iconic example.

Consonance and Dissonance in the Blues

As Susan McClary (2000) observes, “blues musicians privilege a vast palette of sounds that European-trained ears tend to hear as distorted or out of tune” (p. 35). Walter Everett (2004) refers to the tritones and half-steps characteristic of blues as “intrinsically dissonant” (p. 17). Naphtali Wagner (2003) sees the blues as occupying the diatonic major-key system, and the blues scale as violating the rules of that system. (He uses the term “blue notes” to refer to blues scale notes, not to the microtonal pitches discussed above.)

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 (p. 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” (p. 354). Reharmonizing a blues scale note “improves” its status because “instead of being an outsider, it becomes a distinguished member of the club” (p. 355). Reharmonized blues scale notes are transformed into “respected members of the community,” although their African roots remain “imprinted on their identity cards” (p. 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.

Dmitri 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'” (p. 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 (p. 374).

Tymoczko immediately follows his discussion of blues with the example of jazz improviser Warne Marsh playing an E major chord over E-flat major tonality. Tymoczko is no doubt correct that Marsh is intentionally violating listeners’ harmonic expectations in order to create tension. However, I am not aware of any blues players who believe themselves to be playing intentionally “wrong” notes.

Nicholas 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.” In a blues context, this definition does not make sense, since such “dissonant” notes often sound perfectly correct and natural. Hans 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 (p. 105)!

The free blending of major and minor tonality exemplifies the sound of the blues, a fact which I discuss in depth below.

Unlike any other scale in common Western use, the blues scale is a kind of universal harmonic solvent. It can sound correct over any chord in any tune in any American vernacular style (Levine, 1995, p. 230). Some theorists explain the seeming disconnect between the melody and harmony in blues-based music by saying that the relationship does not particularly matter, that there is a “melodic/harmonic divorce” (Temperley, 2007). We could interpret this idea to mean that any melody note would work over any harmony in a blues context. However, this is untrue. There are relationships between melody and harmony and the blues; they simply operate according to different rules and conventions than Western European tonality. Tension and resolution are still there, but the concepts of consonance and dissonance are defined differently. Albert Collins’ song “Don’t Lose Your Cool” includes a fascinating example.

The tune is in F blues. Collins’ guitar melody on the first chorus simply repeats the note F. When he gets to the C7 chord at 0:11, Collins continues to play F. According to the rules of tonal theory, this is a wrong note. The consonant notes on C7 are conventionally C, E, G, and B-flat. In a jazz context, D and A are consonances as well, and even F-sharp would not raise eyebrows. However, F is an unacceptable avoid note against the E. And yet, Collins’ solo does not sound outlandish or dissonant; it sounds like it is well within the conventions of the blues.

While the blues scale sounds consonant within the context of blues tonality, microtonal blue notes can create the feeling of tension and instability that we conventionally ascribe to dissonance. Peter van der Merwe (1992, p. 120) describes blue notes as possessing “melodic dissonance” that is resolved when a bent note resolves to a scale tone. Once again, this idea requires further study.

Dominant Seventh Chords in the Blues

The blues treats dominant seventh chords in a strikingly different way from common-practice European tonal harmony. In the blues, dominant sevenths can be tonic chords, destinations for harmonic closure.

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, p. 346).

The V7/I cadence appears in some blues tunes, though not all of them. Did the blues I7 and IV7 derive from the common-practice V7? Stoia (2010), Benward and Saker (2009) and Everett (2004) all 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. Furthermore, there are many blues songs that never leave I7. Should the I7 chord’s tritone really be considered dissonant or unstable in this context?

Most blues songs use chord progressions, but the chords do not function in the same way that they do in European tonal music. The V7 chord is frequently absent, especially in rural blues (Kubik, 2005, p. 207). Even when scale degree 5^ is present as a root, the chord on top will often lack the leading tone. 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. The sole consistent thread through the harmonies in all jazz styles is the blues, not European tonality.

Even though so many blues songs eschew V7-I cadences, some theorists continue to insist that blues harmony fundamentally adheres to the norms of tonality. One is Walter Everett (2004), who describes blues as consisting of minor pentatonic melodies lying on top of “functional” diatonic harmony. While the blues scale may take up the foreground, by his argument, the blues’ structural harmony is in the major-mode chordal backing ([16]). 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” ([18]). I find this unconvincing at best. When we listen to a song like “Spoonful” by Willie Dixon (1960), which consists entirely of minor pentatonic riffs over a single static dominant chord, are we really supposed to imagine that functional diatonic harmony is hidden somewhere underneath?

Modal Mixture

Since the blues combines elements of diatonic major and minor tonality, some authors understand it as a kind of modal mixture. Ralph Turek and Daniel 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 (p. 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” (p. 594). Philip 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.

Green Onions” by Booker T & the MGs (1962) is a good example of how blues harmony can resemble modal mixture.

In the first four bars, the chords are Fm7, A♭, B♭. All of these chords are built from the notes in F Dorian mode. At bar five, the figure moves up a fourth, and the first chord becomes dominant instead of minor: B♭7, D♭, E♭. The B♭7 is still made from notes in F Dorian, but the D♭ is from parallel F natural minor. (The E♭ belongs to both Dorian and natural minor.) At bar nine, the figure moves up a fifth, and the first chord becomes dominant again: C7, E♭, F. The C7 and F are from parallel F major.

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, many blues songs defy analysis in this way. Consider “I’m Bad Like Jesse James” by John Lee Hooker (1967).

Which tonality is the “native” one here, major or minor? Which tonality is being imported in? I do not believe there is any answer except to say that the song is in E blues.

Groove Harmony and the Blues

If there is a single element unifying all forms of Western popular music, it is underlying groove structure. Anne Danielsen (2006) describes a groove as a short repeating cell with complex internal rhythmic structure and without a larger linear or hierarchical structure. Grooves form the substrate of songs in rock, R&B and other Black American musics. In funk, hip-hop, and dance music, grooves are both the foreground and the background. Blues tonality pairs well with funk grooves, and Tony Bolden (2020) convincingly locates the foundation of funk in the blues. The historical origins of blues tonality are a mystery, as I discuss later, but it may well have emerged hand-in-hand with African-American groove structures generally.

Philip Tagg (2009) observes that the chords in loop-based grooves create a sense of states, conditions, or “places to be”, rather than acting as components of a large-scale tonal scheme. Within these loops, the consonance and dissonance are more a matter of metrical placement and emphasis than intervallic content or voice leading. These loop progressions frequently violate the conventions of Western tonal theory. David Bruce (2021) describes repeated dissonance as the basis of most twentieth century popular music. Over a clip of the guitarist Cory Wong playing a funk groove, Bruce explains that the groove is “based around the simplest kind of dissonant chord, the dominant seventh. That’s a chord that’s thought of as dissonant because it creates a tension that needs to resolve to the tonic” (n.p.). Bruce compares funk to Igor Stravinsky’s rhythmically repeated dissonances, and illustrates his point with a mashup of Cory Wong’s groove and The Rite of Spring. However, this analysis is only valid in the stylistic context of Western European music. Remember that in blues-based grooves, tonic dominant seventh chords are not dissonant, they are consonant. Whatever tension or resolution Wong’s groove possesses, it is not due to resolution of tritones in cadences.

Blues Harmony and the Guitar

There is a natural synergy between the blues and the guitar. This is partially due to simple ergonomics: in standard tuning, the pentatonic and blues scales are easier to visualize and play on the guitar fretboard than the diatonic scales. Adam Neely (2021) connects blues tonality explicitly to the ergonomics of the guitar, pointing out that the open strings form an E minor pentatonic scale, and that playing major chords on the open string roots goes a long way toward creating the sound of the blues. Recall that informally trained guitarists (including the author) typically learn the pentatonic scales first, and then add pitches to them to form additional scales. This approach is not unique to guitarists. Dan 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.

Walter Everett (2004) discounts the significance of the blues scale in rock, arguing that it merely decorates major-mode harmonies with minor pentatonic borrowings. However, while the blues scale may not be a typical feature of rock vocal melodies, it is the bedrock of rock guitar solos. There are many well-known lead guitarists who do not use any other scales. A central stylistic difference between jazz soloists and rock soloists is that jazz soloists will generally follow the chord progression, whereas rock soloists 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 ragtime-style chord progression with several secondary dominant chords. However, lead guitarist Robbie Robertson does not follow the changes at all; he simply plays the tonic blues scale over the entire form.

Blues and the Harmonica

The harmonica was designed in central Europe in the 19th century to play the popular music of that time and place: waltzes, oom-pah music, and light classical. Blowing into a standard diatonic harmonica produces a major triad repeated in octaves. Drawing through the harmonica produces a dominant ninth chord, the V7 in the key of the blown triad. By blowing and drawing, players can produce V-I cadences and the accompanying major scale. Sometime between 1870 and 1920, Black American musicians discovered an alternative way to play the harmonica. They realized that if they mentally reversed the roles of the blown and drawn notes, then the drawn notes became a tonic V9 chord, and the blown notes became the IV chord of the corresponding Mixolydian mode. Furthermore, by drawing too hard, it is possible to bend these notes, making them go flat and thereby producing the blues scale and numerous blue notes.

Blues musicians subvert the intention of the diatonic harmonica’s design with what is “perhaps the most striking example in all music of a thoroughly idiomatic technique that flatly contradicts everything that the instrument was designed for” (van der Merwe, 1989, p. 66). The way that blues musicians creatively misappropriated the harmonica is a neat precursor to the way that rock musicians misappropriated the guitar amp, and the way that hip-hop musicians misappropriated the turntable and sampler. Rayvon Fouché (2006) describes this misappropriation as “black vernacular technological creativity.” There is a clear analogy between the alternative physical approaches to these technologies and the alternative musical thinking that goes along with them.

The Blues Song Form

Blues as a musical idiom is often equated with the twelve-bar strophic form that shares its name. When jazz musicians play a tune like “Sonnymoon for Two” or “Straight No Chaser“, they describe it as playing “a blues.” We must be careful, however, to distinguish between blues as a genre and the blues song form. The twelve-bar blues form is what Nicholas 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. Blues tonality is a more reliable signifier for bluesiness than the twelve-bar 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 for the 1960s Batman TV 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. Andy 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.

Blues Tonality and Genre

Nearly all American popular and vernacular music is informed by blues, but different styles display more or less blues influence. 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? We often explain genre in terms of characteristic rhythms and timbres. We can also delineate genres in terms of how much blues harmony they use. Pop and jazz practitioners already do this, intuitively or systematically. In my own life as a guitarist, I have to know how much blues tonality to use in order to sound more like jazz or country or rock.

Blues tonality is an especially useful marker for distinguishing funk from disco. The two genres are difficult to distinguish in any other way. For example, funk and disco share the same rhythms (and they share these rhythms with hip-hop, R&B, and some rock.) The real distinguishing factor is harmony: funk mainly uses blues tonality, while disco mainly uses diatonic or jazz-based harmony. Compare “Jungle Boogie” by Kool and the Gang (1973) to “Love You Inside Out” by the Bee Gees (1979).

Both songs have undeniably funky grooves. However, “Jungle Boogie” has no chord changes, and its melodic components are comprised entirely of blues tonality, embellished with some jazz-inflected chromaticism. “Love You Inside 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 smoother and more polished timbres to pushes their music away from funk and firmly into disco.

It is possible to imbue nearly any piece of music with blues feel by embellishing or replacing its melody and harmony with the blues scale and blues tonality. 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 blues tonality throughout. Franklin also adds additional blues feel via rhythm and pitch play. The end result is much bluesier than Simon and Garfunkel’s version.

Blues tonality nearly always goes hand-in-hand with syncopation and swing. An interesting example from 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.

Blues and Rock

Rock harmony is mostly diatonic, but it features some characteristic deviations from the conventions of tonal harmony as well. These deviations are mainly due to the influence of the blues. This influence is pervasive; many early 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, p. 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, p. 22).

Trevor DeClercq and David Temperley’s study of rock harmony (2011) is a useful reference point for the influence of the blues. 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’. (Note that this list uses a very broad stylistic definition of rock.) 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, 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, Rob van der Bliek (2007) describes the dominant seventh sharp nine chord, nicknamed the “Hendrix chord,” as adding a “blues tonal element” (p. 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” (p. 345).

The Origins of Blues Tonality

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 European practice. So where did blues tonality come from? We may never have a single unambiguous answer, but there are several plausible theories. Given the hybrid nature of most American musics, we should expect nothing different for the history of blues tonality.

Philip Tagg (2009) is one of many authors who explain the blues scale as an extension of the minor pentatonic scale. Mark 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. Ande Jaffe (2011, p. 37) 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 with the diatonic I, IV and V chords.

An alternative explanation of the blues scale can be found in Peter 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.

Court Cutting (2018) speculates that the blues scale might originate in the “harmonic half diminished seventh chord”, the frequency ratios 5:6:7:9, giving a just intonation chord 1, b3, b5, b7. Cutting’s audio example of this pitch collection sounds quite convincingly bluesy. He points out that the harmonic half diminished chord is the next four-note chord up in the harmonic series from the harmonic dominant seventh chord (4:5:6:7) frequently heard in barbershop quartet harmony. Given that barbershop harmony likely arose in the same African-American communities that birthed the blues, this connection is probably not a coincidence. Barbershop quartets use the harmonic half diminished seventh chord as a rootless voicing of a dominant ninth chord.

Did Blues Originate in Africa?

It is natural to assume that those aspects of the blues that differ from European musical tradition must have originated in West Africa. Gerhard 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, including:

(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 (pp. 191-192).

Lucy Durán (2013) points to Bamana griots in the middle Niger valley as an example of a possible point of origin for the blues. She cites a griot song called “Poyi” that predates the European slave trade, according to oral tradition.

However, African practices are not the only plausible roots of blues harmony. Various European folk musics, particularly those of the United Kingdom, also use thirds lying between the equal-tempered minor and major thirds. The “ladder of thirds” is also common to British folk music. It is 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, p. 145).

We must also remember that enslaved African-Americans did not only interact with European colonists, but also with Native Americans. Ted Gioia (2013) argues that, contrary to widespread assumption, the American colonies and early states were not empty of Native peoples. Furthermore, while West African griot songs might have some sonic similarities to the blues, they are quite different in their social purpose and content. Griot songs typically praise local chiefs and detail their ancestry, rather than expressing the singer’s personal feelings. Morgen Stiegler (2009) explores numerous vectors for Native American influence on jazz (and therefore also blues): the Native ancestry of many Black Americans, including numerous blues and jazz musicians and the extensive contact that Native Americans and Black Americans had, especially in the Southeast. Stiegler also points out that the personal and introspective nature of blues lyrics are a shared characteristic of Native musical traditions, and that the foursquare stomp rhythms and pentatonicism of Native musics are plainly audible in the blues. The vocalistic blues slide guitar style also shows clear influence of Native Hawaiian slack-key guitar.

Music Education and the Blues

Why is it important that formal music theory courses discuss blues tonality? Blues musicians have learned by ear for over one hundred years; surely they do not need formal instruction. I believe that there are two main reasons to nevertheless include it in standard theory curricula. First, the exclusion of such a profoundly important concept as the blues sends a broader message of exclusion. Second, the failure to educate non-blues musicians about the blues results in widespread misunderstanding, with sometimes ugly results.

Aretha Franklin’s classic song “Chain of Fools” (1968) is an archetypal example of blues tonality. It is nominally in C Dorian mode, but the first complete chord in the song’s intro is a C7. The lead guitar and vocals include numerous E naturals, F-sharps, and blue notes. Consider the line “I ain’t nothin’ but your fool” in the first verse, at 0:41 in the recording: Franklin begins the word “fool” on F, moves it down to E-flat, and then concludes it by sliding up to E natural.

There have been several arrangements of “Chain of Fools” for school choirs and wind bands. The choral arrangement by Greg Gilpin (2010) carefully attends to many nuances of the song, but it is entirely in C Dorian mode. Gilpin writes the C7 in the intro as Cm7. There are two possible reasons for such inaccuracy. The first is that Gilpin consciously decided to simplify the song for the benefit of inexperienced student performers. This choice would be understandable, if regrettable. However, it also seems unlikely, as the arrangement is a sophisticated and challenging one generally. The other possibility is that Gilpin did not even hear the E naturals, or that he thought they were out of tune E-flats.

The marching band arrangement by Doug Adams (2019) similarly removes all of the song’s major/minor ambiguity, though he does include the F-sharps. In their marching band arrangement, Dallas Burke and Carl Major (2013) also omits the major thirds, and inserts several V-I cadences. The V chords include sharp ninths, presumably to give them a bluesy feeling, but their presence undermines the original’s static groove harmony. All of these arrangers were presumably motivated by a desire to “diversify” their repertoire, but by removing the blues tonality from “Chain of Fools” (and adding functional Western harmony inappropriately), they are not doing the song justice.

Conclusion

Music theory is important because it sets students’ expectations for what is possible. If students only learn the harmonies of Western European tradition, then they will struggle to understand the blues-based harmonies that pervade the past hundred years of Western music. Worse yet, students may come to believe that such harmonies are not worth studying at all. Meanwhile, I have met many excellent musicians in the blues, rock, dance and hip-hop idioms who abandoned their study of music theory because they were discouraged by its seeming irrelevance to their needs. Music is a site where social and political values are contested, symbolically or directly. By failing to engage harmony that does not descend from Western Europe, traditional harmony pedagogy reveals the lingering effects of the music academy’s white supremacist past. It is time to leave such atavistic and exclusionary practices behind.

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7 thoughts on “Blues tonality

  1. Thanks for that, I have been thinking about this subject for quite some time. Elaine perhaps needs to listen a bit more. Trying to define blues tonality, and tonality is what it is, tonality being knowing or feeling what the central tone is, using traditional theory based on European harmony of the 19th century is quite difficult, if not impossible. I am thinking that that the blues tones, and there are many, are perceived as alterations of traditional tones, meaning those that appear on the piano, that create an emotional response in the listener based on their alterations, sharpening or flattening, from traditional tones. Whatever happens in the music, we still feel the tonic as the tonic and not as anything else even if the chord is a dominant 7th, despite any inclusions of what would normally be considered in standard theory as a tonic to that dominant. E.g. A7/// G/D/ A7///. A7 is the tonic, not D. In other words, I agree with you entirely. Coming up with a way to teach this, besides saying “just use your ears”, is another thing.

  2. Thanks for reading all of that academic stuff on blues. Now I don’t have to bother!

    But seriously, my main question is what do you mean by “tonality” in the phrase “blues tonality”.

    In classical (and jazz) theory, “tonality” refers to which note is “home”. This question only makes sense, from the perspective of theory, in situations where this home changes during the course of a piece of music.

    Because if the tonic never changes, you don’t really have to ask questions about why that note is the tonic, and not another note. Or, what you might need to do to establish a different home, or to get back to your original home.

    From my perspective, these are the questions that justify the utility of any theory of harmony.

    What questions are you answering, that the concept of tonality plays a part?

    It seems to me that you are more interested in describing the feel of blues, and not its harmonic functions.

    Which is great inquiry, but I don’t think what you’re investigating is “tonality”. It’seems probably closer to “modality”.

    While I agree that blues has a vast array of sounds and pitches that are difficult to categorize, or are completely uncategorizable, the aspects of blues that do relate to the establishment of tonicity are exceptionally congruent with Western common practice, jazz and most other folk musics in America.

    • I say tonality rather than modality because blues is more like major and minor than it’s like Mixolydian or Phrygian. Just as the major and minor universes incorporate various scales and modes, so does blues (the blues scale itself, Mixolydian, Dorian, etc.)

      I think you do have to talk about harmonic function in blues even if the tonic doesn’t change, because there is an awful lot of confusion out there about what the tonic of a blues song is. I’ve seen people assert that a blues song in A is “really” in A major, or C major, or even D major.

      My whole point is that blues harmony is only difficult to categorize within the major/minor/modal framework. When taken as a fundamental category unto itself, it makes perfect sense. I want our theoretical language to match the listening experience. Blues isn’t at all difficult to understand aurally, so why should we made it so difficult to understand theoretically?

      I dispute that establishment of tonality in blues is congruent with common practice. In common practice (and jazz for that matter), you establish the key center by looking for cadences, for V-I progressions or the equivalent. Blues asserts the tonic through metrical placement and reassertion only, since V-I is often not present. A lot of bad analysis of blues is based on looking for cadences, thus the ridiculous assertion that blues in A is really in D because of the A7 to D movement.

    • The overtone scale has flat 7, and flat 5 way in the upper partials. Flat 3rd, not really. The closest scale to the natural overtone series is Lydian dominant. A great scale, but more Eastern European than bluesy.

  3. Thank you for taking the time to write this, Ethan! We’ve all been thinking it for a long time, of course, but it needs to be said, over and over, until theory programs change to incorporate the music we know.

    I remember that in his improvisation class at Hampshire College, Yusef Lateef said that the primary scale in audiophysiopsychic music (his name for jazz) was the mixolydian (major with a lowered seventh), and that was the scale for young improvisers to learn first and best, not the major scale.

  4. Right on, brother. A well thought out and sensible piece of writing.

    I wrote a little thing on Quora about the limited utility of time signatures in the blues, kind of related. You’ve probably written something better on the subject here on your website.

    http://qr.ae/Z1aqG

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