Topic: Harmonic Complexity/Content in Country Blues--Where Did It Go?

[Johnm]

Hi all,
I have been thinking a long time about the question of what happened to the degree of chordal complexity and content in the country blues as it has evolved in the period since it was first recorded.  We are accustomed, rightly or wrongly, to thinking of creatures, artistic styles, or anything else that changes over time, as evolving from greater simplicity and lack of specification to greater complexity and  more specification over time.  Yet in the country blues, almost all of the recorded performances showing an expanded chordal vocabulary, extending well beyond the I, IV and V chord, were recorded either within the first ten years of country blues being recorded, or were recorded by musicians who were already active in that period, but who didn't get a chance to record until later years.  How do you explain the music that Blind Lemon Jefferson, Blind Blake, Lonnie Johnson and Papa Charlie Jackson played evolving into the music that Lil' Son Jackson, Dr. Ross, John Lee Hooker, R. L. Burnside played?
   * Generational differences in popular musical style are very short, five years or less, so that the generational age difference between the first and second groups of musicians named above is not nearly as far removed as their generational stylistic difference.  There is every reason to believe, based on their music, that Jefferson, Blake, Lonnie Johnson and Papa Charlie Jackson all heard Ragtime and Classic Blues, and were influenced by them.  Likewise, influences of the Parlor guitar craze of the late 1800s and pre-Blues ditties can be heard in the music of John Hurt Elizabeth Cotton, Henry Thomas, and Frank Stokes.  There appears to be virtually no trace of circle of fifths progressions associated with Ragtime or the expanded chordal vocabulary of Classic Blues in the music of Lil' Son Jackson, Dr. Ross, John Lee Hooker, R. L. Burnside, or Robert Belfour, for that matter.  It would seem that the greater the remove there is between a solo country blues guitarists's years of greatest career activity and the era of Ragtime and the Classic Blues, the less likely it is that the guitarist will use chords other than I, IV and V.
   * It may be that thinking of the music of Blind Blake, Lonnie Johnson and Papa Charlie Jackson as Country Blues gives an unrealistic impression of the degree of chordal complexity that most country blues players of the period 1926-1936 employed in their music.  Even during the early years of recorded country blues, there was a strong strain of blues recorded with a very pared-back harmonic content.  Think of Rube Lacey's "Mississippi Jailhouse Groan", the slide pieces of Sam Collins and King Solomon Hill, and the early solo recordings of Henry Townsend.  In the main, these are one-chord pieces.  Is there any reason to assume that there were more guitarists out there who went un-recorded who had a Papa Charlie-like degree of chordal sophistication, than there were guitarists who played one-chord numbers?  I don't think so.  I think it is more likely that the kind of sophistication that Lemon, Blake, Lonnie Johnson and Papa Charlie Jackson showed, while arising naturally out of the music that was popular in these players' formative years, was nonetheless the exception rather than the rule among country blues guitarists, even during the years when these players were most popular.
   * In the mid-30s and beyond, it seems that whatever impulse there was toward a more chordally complex treatment of the blues went into ensemble music-making like the Harlem Hamfats, and the various Chicago groups led by Tampa Red and Bill Broonzy.  More complex yet were the Jump Blues of groups like Louis Jordan's while the Blues as played by boppers like Charlie Parker and Dizzy Gillespie employed a harmonic language closer to that of Jazz Standards than that of "Mississippi Jailhouse Groan".  Solo country blues guitarists playing chordally complex music in the post-1935 period are as rare as hen's teeth, and where they do occur, they were almost invariably born prior to 1910.  Bo Carter and Rev. Davis were both born before 1900.
   * Changes in the rhythms that country blues employed in the post-1930 period worked against chordal complexity.  In the pre-1930 period, recorded country blues was most often played in cut time, with a 2/2 feel.  John Hurt never recorded a piece in 4/4 in his life, nor did Charlie Patton ever record a shuffle.  The shuffle feel, with its 4/4 meter and under-lying triple feel, was a rarity in the 1920s.  The vast majority of country blues players recording then worked in the duple feel common to Ragtime, pre-Blues and the Minstrel songs of the 1900s.  One of the few musicians anticipating the coming rhythmic direction of the blues was Memphis Minnie, in her duets with Kansas Joe.  Minnie is also unusual for her formal and metric consistency.  She was a great player and played great leads, but when you think of it, it is all pretty much done over I, IV and V, with the exception of an occasional I-VI-II-V number.  The shuffle survives today as the fallback groove of choice for Chicago blues bands and blues jams around the world.  The very predictability of its accompanying chordal progression works in its favor, for it allows musicians who may never have heard the song they are playing along with to join in, so long as they know what to do when someone says, "Shuffle in G".
   * Adoption of the electric guitar as the accompanying instrument of choice also made chordal complexity of less significance than in the era when Blind Lemon and Blind Blake had to fill up musical space on instruments with little or no sustain.  One of the advantages of the electric guitar is the greater sustain it affords the player, thus allowing a more vocal approach to phrasing that was pretty much available only to the best slide players in the pre-amplification era.  When what you're playing sustains longer, you can get by with playing less.  Moreover, if you think of the role of the solo country blues guitarist as being an accompanist to dancing, creation of a strong danceable beat will trump chordal complexity for a dance crowd every time.  That fact goes a long ways toward explaining the popularity of an artist like Dr. Ross, who never met a V chord he liked, but was a groover par excellence.  In many ways, the model of a perfect present-day country blues guitarist as dance accompanist is Robert Belfour, who combines tremendous grooving with smoking bass runs, sinuous treble fills and powerful singing.
It seems possible that Country Blues, at least as played by non-revivalist musicians in the latter part of the 20th century, may have returned to the the musical materials that the Country Blues started with about a century earlier:  heavy emphasis on pulse and phrase length rather than meter, as driving forces, heavy emphasis on riffs for melodic content, and relatively little emphasis on chords or chordal content.  Whatever the explanation is for the rise and fall of the role of harmony in country blues, if what we're left with is the music of Robert Belfour, we're doing pretty darn well.

All best,
Johnm

[dj]

Interesting post, John.  I've been thinking about it all day, and I've come to a few conclusions.

First, although it's counterintuitive, I think it's the tendency of all styles of music to lose complexity over time.  When a style of music is young, it has few conventions and a lot of experimentation, and gradually, as the style ages, it acquires more and more conventions and becomes more and more formalized.  You can see this, for example, in 18th century French instrumental suites, which started out as loose collections of any dances the composer wanted to include, and ended up in a very rigid, formalized set of dances and key relationships. 

I think the tendency is especially apparent in the phonograph age.  In the early days of recording any musical genre, record companies don't really know that much about a style.  They know, for example, that some guy singing "blues" with an acoustic guitar is selling lots of records, so sign up every guy who sings blues with an acoustic guitar and see what happens.  After awhile, they begin to get an idea for what "the blues" is, and consciously mold their artists to that style.

The tendency to record almost anyone who walked in the room and could sing was exacerbated in the twenties as record companies got the idea that if you recorded someone from Bristol, Virginia then people in Bristol would buy a phonograph to hear his record, and once they had the phonograph, they'd want to buy other records.  So if the Carter Family had turned out to be minor recording artists, sales-wise, at least the fact that they'd recorded would have sold some phonographs in their hometown.  By the mid-thirties, the record companies had dropped this attitude and were more focused on artists with a more homogeneous sound who could command a broad audience.

One thing that you touch on that I really wish I knew more about is how dance styles affected the development of the blues.  It's the chicken and egg thing.  Did musicians develop a shuffle rhythm because someone was doing a dance that fit that, or did dances to shuffles arise when musicians started playing that rhythm?  Anyway, I have always had the feeling that if I knew a lot more about the dances that people were doing to the blues over the years, I'd know a lot more about why the blues evolved the way they did.       

Well, that's it.  Thanks for your patience.

David

[GhostRider]

Hi:

Actually I've thought a lot about this, more in connection between country blues and early Chicago electric blues.

I think one point that you, John, didn't address on why country blues became more harmonically simple is that maybe it didn't!

 Entering in on the '30 was the Depression, of course. The record companies could not afford to record artists who might not sell "just on spec". They relied more and more on proven hitmakers (Lonnie J., BBBroonzy, Tampa Red etc.) and fomulistic approaches they thought would sell (survival). Thus harmonically simpler tunes would be the consequence, a proven formula.

It's quite possible that the more complex folks were still out there, but wern't being recorded. That, the distance from when ragtime was more popular, and the availibility of records, providing hits to emulate rather than "figuring it out yourself". may be reasons for a harmonically blander product.

The thing I do about the Greatest Country Blues Hits of 75 years old has made me make the yearly transition, and I've noticed the change.

Or not,
Alex

[Muddyroads]

So you are saying in an ever more sophisticated and technological world the use of the one chord blues form  grew while the more  complex chordal approach waned?  My question then is, what was it in the chordal simple pieces that reached the players and listeners/dancers who responded to this music.  The corporate types were only interested in what would sell.  What sociological pressures lead to this music taking over for harmonically more advanced music?  Was it the rise of jazz and later R&B? 

There is a security in a one chord vamp.  A sureness in its incessant.  Electric guitars make it more powerful.  There is something in the I-IV-V blues changes that persists.  As a forty year + fan of the blues, I find these things still comforting, moving, exciting  and only occasionally boring.

Mud

[Cambio]

I think that the harmonic complexities might have had something to do with the popular music of the turn of the century, which is what all of the early blues greats came up on.  Not just rags, but marches, waltzes, comic songs, coon songs and the like.  If you start listen to some of those old records of people like Collins and Harlan, or Billy Murray, you start to hear hints of where some of the early blues players got some of their  material.  Indeed, some of the great women blues singers started out singing poplular music of the day in tent shows, think of Ma Rainey, before they had even heard of blues.
Maybe the blues lost that complexity after that sound became old fashioned and no one wanted to hear it anymore.  I'm currently reading a biography of Sam McGee and there definately came a time in country music when people didn't want to hear Sam's kind of music anymore.  Instead they favored the simpler music of people like Roy Acuff and Bill Monroe.  The music started to become more standard and sterile.  There was no place for an old medicine show veteran who had apprenticed with Uncle Dave Macon.  What a shame.

[Johnm]

Hi all,
Thanks for your responses to all who answered my post. You've given us a lot to chew on, certainly. I think, David, your point about styles simplifying as they evolve is well taken. It does seem that before a style's identity is fully formed, it encompasses a broader range of influences. As it evolves, it becomes more language-specific, and undergoes a sort of formal hardening of the arteries. This is especially true of the blues, and the movement of the blues from a solo player/singer music to an ensemble music accelerated the adoption of blues conventions, e.g., 12 bars, each of four beats, the IV chord landing on the fifth measure, etc. The need for musicians in an ensemble to arrive at the same place at the same time creates a certain pressure for hard and fast formal guidelines. To the extent that less rigidly structured approaches to the blues survived in the post-30s era, they almost always survived in the playing of soloists, not ensembles.
Ensemble playing need not necessarily result in "paint by the numbers" music, though. As Todd points out, in the early years of country blues, the acceptance of a host of popular music types that ensembles of the era played right along with blues in their performances had the effect of making both the blues and the non-blues material seem fresher, and less bound by formal conventions. Bands like the Mississippi Sheiks or Peg Leg Howell with Eddie Anthony and Henry Williams sound loose as a goose when they play blues, as they do when they play "Turkey In the Straw" ("Turkey Buzzard Blues"). Part of the diffference between these earlier bands and later bands is that the idea of a "blues band", which confines itself to the performance of blues only, is a later development, just as the idea of the "blues musician", who only plays blues, is a later development. Can anyone think of a blues musician earlier than Henry Townsend, who recorded more than a couple of titles and who only recorded blues? I can't think of one right now.
Alex's point about the record companies contributing to the reduction of harmonic content in blues and formularization of the blues is right on, I think. Commercial record companies for the most part, I think, live for two things: Hits, and Covers Of Hits. To the extent that the ensemble recordings of Tampa Red and Big Bill Broonzy sold, they spawned more imitators, speaking the same musical language. And there was much to admire in the smoothness and tightness of the musicianship involved in this kind of music-making. Listeners who would mourn the passing of rougher and more varied earlier styles were probably in the minority.
As time passed, though, this trend resulted in a tipping of the balance of the musical components which combine to comprise the blues. In the early years of recorded country blues, rhythm, melody, harmony, and quality of sound existed in a close to par basis in much of the music, though harmony did did most often take more of a back seat to the other qualities. I think that balance is part of what makes pieces like Lemon's "Bad Luck Blues", Charlie Patton and Henry Sims' "Elder Green Blues" or Papa Charlie Jackson's "Airy Man Blues" so beautiful and strong. As the years went by, harmony's role in the country blues progressively diminished, as did melody's, and rhythm and quality of sound came to predominate. A parallel development occurred in Pop Music, as it moved from the era of the Gershwins, Jerome Kern, Irving Berlin and other writers of that ilk into Rock and Roll.
I think what we're left with is undeniably strong, when played as well as it can be played, and as Muddyroads points out, it is"comforting", in addition to being "moving exciting and only occasionally boring". Prokofiev once said, "Audiences want to be lulled", and I think that sense of predictability and knowing what you are going to get explains the popularity of much blues today. The lack of variety may also explain, though, people who categorically state, "I don't like blues".
One other point that occurred to me about the diminishing role of harmony in country blues over the years, is that I referenced that waning role to the loss of any kind of influence from Pre-blues, Ragtime or Classic blues material in most post-1935 solo blues musicians. I realized, though, that I could think of at least two solo blues musicians of the later years with expanded chordal vocabularies that did not derive from Pre-Blues, Ragtime or Classic Blues: St. Louis pianist Walter Davis and Robert Pete Williams, of Louisiana. Both Walter Davis and Robert Pete employed modal sounds to expand the harmonic vocabulary of the blues, and I think the directions they took in their music show new ways to sound in the music that are nonetheless appropriate to the style. The possibilities they made clear in what they did are still waiting to be explored and utilized.
All best,
Johnm

[blueshome]

What an interesting thread. I've been thinking about this since John mentioned his ideas at Northampton.
 I think a major factor is sociological - the audience moved.

The period under consideration was when the largest migrations were taking place to the cities from the South. Thus old social structures were destroyed and new ones formed. Perhaps the opportunity to learn music from the local home town guitarist or other musician was reduced so that direct aural transmission lessened. Also surely newcomers to the city, like all immigrants tend to want to lose their "country" ways and become more "civilised" thus turning their back on downhome styles.

My thesis is thus that, in addition tp the very valid points made by others, there was less demand for the older styles, and there may have been a smaller pool of musicians versed in them over the course of the period in question. Music in general being a business, folks would play what people wanted to hear and the old style would diminish at the same time as its skills were being lost (except to us middle aged white freaks who dug it 30 years later).

[Muddyroads]

I think that the harmonic complexities might have had something to do with the popular music of the turn of the century, which is what all of the early blues greats came up on.  Not just rags, but marches, waltzes, comic songs, coon songs and the like.  If you start listen to some of those old records of people like Collins and Harlan, or Billy Murray, you start to hear hints of where some of the early blues players got some of their  material.  Indeed, some of the great women blues singers started out singing popular music of the day in tent shows, think of Ma Rainey, before they had even heard of blues.

Cecil Brown, in his book Staggerlee Shot Billy , discusses this issue.  As much of the Afro-American  music was orally transmitted, he makes a case for the music traveling from the bordellos where ragtime was played,, to being sung by stevedores .  It is a short trip to the fields, etc. as the music made its way through the community.  The melding of styles and the eventual  solidification of  a  I-IV-V format  was part of the  reaction to cultural forces then at play.  Ragtime died out as swing started to emerge .  The music smoothed out, if you will with boogie-woogie, an immensely popular  form and the room for improvisation over a simpler  chord structure allowed for  blues to become what it is today.  I may be over simplifying  this but music, like water will take the course of least resistance in at least in  its popular form.

My 2 cents,

Mud

[waxwing]

I think another factor that needs to be considered in this discussion is the regional differences that were apparent in the earliest recorded "country" blues. This came up for me, in a discussion over on the 'Shed,  arguing against Elijah Wald's "blues was created by the record companies" theory .

It seems to me that, if the source of all the musical awareness of the earlier players was the popular music at the turn of the century, there would have been a lot less regionalism. I think the route from Tin Pan Alley to the fields was not quite so smooth. Perhaps a great deal of regional "folk" music was created by the isolation that poor antebellum  blacks lived in. A song, taught to plantation slaves by their white masters, could have taken many different forms as it was passed down from mentor to child over several generations in a rural area with little or no contact from mainstream pop music of the antebellum era. Perhaps these regional styles could have been influenced by an earlier musical heritage, especially in areas where slaves were brought in shortly before emancipation.

It is clear that the southern blacks were still used as an enslaved workforce, but no longer being a possession of the plantation owners, representing monetary wealth, their welfare was no longer much of a concern. They weren't really an issue for anyone until they were recognized as a viable market. Perhaps this occurred because blacks like Scott Joplin started to create music that influenced the white market.

I don't know when the tent shows that led to the blues queens actually started, but, to my limited awareness, this seems to be one of the earliest attempts to mass market music to blacks. There may have been an element of wanting to learn the new "pop" tunes by the local rural musicians, but I don't think that their existing "folk" repertoire would have been so easily dismissed. I think there was a much stronger sense of community at the turn of the century and "folk" music is a strong part of community identity. The pop tunes would have probably been transformed to fit the local styles. Being children of the Transient Age, we often overlook these strong social sensibilities.

Of course, all this was eroded by the transience brought about by the mobility of the 20th century. When blacks learned that there may be a somewhat better life somewhere else, whole communities almost dissappeared or were transplanted to Chicago and other parts north and squeezed into neighborhoods with many other "communities". Not only did sense of community break down, but so did family structures in these communities. Having lost these landmarks of identity, perhaps for many the only sense of identity was one's race. It seems natural that the regionalisms of the music would disappear.

Of course, the record industry had a homogenizing effect, as well. Being easily able to hear other styles in any juke box as opposed to the occasional touring show, made musicians of the late '30s much more able to transform their own style.

As you said, John M, generational differences occur every 5 years. Quite a few would have gone by in relative isolation between the Civil War and the advent of the 20th century. Strong regionalisms were created and certainly have to be considered in addressing the transformation of this music we call blues.

All for now.
John C.

[Johnm]

Hi all,
It does seem likely that migration could have an effect on the music by uprooting people from their past or sense of history associated with where they had lived for as long as they could remember. Similarly, the effect of such dislocations combined with the ability to market musical developments as they occurred to a broad audience via recordings must have worked to change the music too, and smooth out regional differences in musical styles from the pre-mass media era. Why the changes should have resulted in a diminishing of the role of harmony in country blues remains a mystery, though, and will probably stay so.
It may suffice to attribute the changes to two things: generational evolution of the music and the ability of recordings to influence the directions the music evolved. People generally limit their nostalgia for the Pop Music of the past to the Pop Music that was popular when they were in their teens and early twenties. Nothing seems so remote or out of date as the Pop Music of the recent past. It is not hard to imagine young Blues record buyers of the mid-1930s feeling like the music of such 20s icons as Lemon Jefferson and Blind Blake was hopelessly out of date. And to the extent that the earlier music spoke of country matters, mules, etc., it must have seemed all the more out of touch to listeners residing in large industrial northern cities. Musicians always want to be on the cutting edge, too, and for young musicians in particular, part of what is involved in being on the cutting edge is rejection of the music of your forebears.
As long as the music remained popular and people continued to play it, it would continue to evolve. It is interesting that Jazz and Blues evolved in opposite directions with regard to their emphasis on harmony. In Jazz, harmonic complexity and exploration have been hallmarks of the music since the beginning of the Bebop Era, despite a few hold-outs like Ornette Coleman and Albert Ayler. Country blues evolved in the other direction, with an eventual paring down of harmonic content, so that many of the solo players of the 50s and 60s specialize in one chord numbers. As far as assigning causes for these changes goes, it is probably too complex a result to come up with simple explanations.? It had to turn out some way, and this is how it turned out.
All best,
Johnm

[Rivers]

This may or may not be true but here's what I have believed for some time. Provenance was (possibly) some sleevenotes, plus comments I read elsewhere by Big Bill Broonzy. I'm no expert on record labels so it may be hogwash.

As I understood it the push to record ensemble playing kicked in strongly after the depression. This was to compete with jazz and find a wider market, rural blues was being increasingly looked down upon. I believe this movement was spearheaded by Lester Melrose, a slightly dodgy character heading up the Bluebird label. So we see great solo players like Tampa Red teamed up with various other Bluebird artists, Broonzy w/Gillum, etc.

Net result was a move toward a formula that disparate musicians meeting for the first time could intuitively pick up. Quirkiness and broken timing was out the window, as were complex sequences beyond the common ragtime ones. The dreaded bland 12 bar blues bloomed like a toxic algae and became the cliche that laypersons usually think of as the blues.

Probably seemed like a great idea at the time but ultimately it choked the delicate flowers of rural blues. We should learn the lessons of history but quite what that means I'm not too sure.

[Johnm]

Hi all,
I was thinking about this topic again recently and remembered one player who was active in both the pre and post-War periods, and whose post-war recordings continued to show a great degree of harmonic content and sophistication: Jesse Thomas. I heard a tune of Jesse Thomas's recorded in the early '50s, maybe 1952, on a CD Phil Thorne loaned me at the EBA Blues Week last summer. Unfortunately, I can not remember the name of the song, but Jesse's playing on it was a real ear-opener.
The song was an A blues in standard tuning, and for his primary voicing of the A chord, Jesse Thomas chose the following (strings number from 6th to 1st):
0-4-5-2-x-x

Jesse was thus voicing an A7 chord, starting at the 6th string, 5th-3rd-7th-Root. It has a beautiful, deep smooth sound.? And what was particularly slick was that when the song resolved to the IV chord in the fifth bar, he fingered the D7 chord so:
0-3-4-2-x-x

This is a rootless voicing of the D7, and it works out as 9th-7th-3rd-5th. There is a beautiful economy in the way he switches from an A chord to a D chord by simply moving two voices down one fret, while keeping the other two voices (on the 6th and 3rd strings) the same. The elegance of the movement between the two chords wouldn't count for much if it didn't sound good--in fact, it sounds great.
I find instances like this really encouraging, because they make me feel like the musical language is not played out yet, and that there are still little nuggets of this type to be found. It also illustrates that while the post-War harmonic language of the blues may have been pared back in the main, in the case of individual exceptional players, a complex language was still being spoken and innovations were being made.

Edited 12/18 to pick up correction from Waxwing
All best,
Johnm

[Bunker Hill]

As I understood it the push to record ensemble playing kicked in strongly after the depression. This was to compete with jazz and find a wider market, rural blues was being increasingly looked down upon. I believe this movement was spearheaded by Lester Melrose, a slightly dodgy character heading up the Bluebird label. So we see great solo players like Tampa Red teamed up with various other Bluebird artists, Broonzy w/Gillum, etc.

Melrose recalled it thus:

"I believe it was in the later part of 1928 that I met up with Thomas Dorsey, who was quite a composer as well as the leader of the Hokam Boys. They recorded the selections Beedle Um Bum and Sellin' That Stuff on Paramount and the record was a tremendous seller. About a year later McKinney's Cotton Pickers recorded the same selections for RCA Victor. I also recorded Big Bill Broonzy on Paramount and Gennett Records.

In 1930 I received a request from the American Record Corp. to record some of my blues talent. This company had various labels for chain stores. I got together a dozen musicians and vocal artists and went to New York City and recorded about thirty selections for them. The vocalists consisted of the Famous Hokum Boys (Georgia Tom Dorsey, piano; Big Bill Broonzy and Frank Brasswell, guitars). The records turned out very well and I made several more trips with artists to New York for recording sessions. There was very little recording being done in 1932 and 1933 due to the effects of the Depression.

However, in February of 1934, taverns were opening up and nearly all of them had juke-boxes for entertainment, I sent a letter, which was just a feeler, to both RCA Victor and Columbia Records, explaining that I had certain blues talent ready to record and that I could locate any amount of rhythm-and-blues talent to meet their demands. They responded at once with telegrams and long distance phone calls. From March, 1934, to February, 1951, I recorded at least 90 percent of all rhythm-and-blues talent for RCA Victor and Columbia Records.

Along with the Famous Hokum Boys and Big Bill Broonzy, I recorded Washboard Sam, the Yas Yas Girl (Merline Johnson), Tampa Red, Lil Green, the Four Clefs, Big Boy Crudup, St, Louis Jimmy, Roosevelt Sykes, Memphis Minnie, Curtis Jones, the State Street Ramblers, Roy Palmer, Jimmy Yancey, Joe Williams, Walter Davis, Sonny Boy Williamson, Doctor Clayton, Lonnie Johnson, Peter Chatman (Memphis Slim), Tommy McClennan, Big Maceo Merriweather, Amos (Bumble Bee Slim) Easton, the Cats and the Fiddle, the Dixie Four, Leroy Carr, Junie Cobb, Lovin' Sam Theard, Jimmy Blythe, Victoria Spivey, Johnny Temple, Dorothy Donegan, the Big Three Trio (Leonard Caston, piano; Bernard Dennis or Ollie Crawford, guitar; Willie Dixon, bass), Jazz Gillum, and many others."
[extracted from My Life In Recording published in The American Folk Music Occasional, Oak, 1970 p.59-61]

[chipmonk doug]

Wow, ya'll know a lot.  I just pick some music. 
Learn more all the time reading this stuff.

[waxwing]

John M, this is reminding me of the double stop voicings Steve James taught us on the mandolin this summer. Let's see if I can remember this correctly without getting out the mando or class notes. In G, play the G7 by fretting the 7th (F) on the 3rd fret of the 3rd pair, and the 3rd (B) on the 2nd fret of the 2nd pair, you could go the the IV chord (C7) by moving the form down one fret, getting the 3rd (E) at the 2nd fret of the 3rd pair and the 7th (Bb) at the 1st fret of the 2nd pair. Then just move the form up two frets to get the V chord (D7). Making for a very simple comp in G. I realized this was because the interval between the third and the dominant 7th is a tritone, a flat 5th, or exactly half of an octave, i.e. the interval from the 3rd to the 7th is exactly the same as the interval from the 7th to the next higher 3rd. I started to get an idea of just how important the tritone is.

BTW, I think you have a slight error in your description of the A7 voicing above. Shouldn't the open 6th string be the 5th?

Thanks for bringing this over to the guitar for me.

All for now.
John C.