The Jazz Guitar Chord Dictionary
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  1. #1

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    I have heard that a 12 bar blues really in three keys?

    Is this true? how?

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  3. #2

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    Because a 12-bar blues consists out of 3 dominant 7th chords that can be considered as a V (dominant 7) of a key?

    So if you play a blues in Bb, you play the Eb major scale for the Bb7, the Ab major scale for the Eb7 and the Bb major scale for the F7.

    This is one (of many) ways to approach a standard 12-bar blues, but it would sound much more jazzy than just playing the pentatonic minor scale or the bluesscale (with extra b5) of the tonica..... it wouldn't sound like John Lee Hooker!

  4. #3

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    Little Jay posted a good answer to the question, but I'll just expand in a different direction.

    When I first started playing blues, I remember reading on someone's website where he was trying to describe why the blues sounds the way it does. He made a great statement that went something like this: The dom 7th chords create tension that longs for release, so we want to perpetually release it, but instead of releasing it, the blues just gives you another dom 7 so there is never a fully satisfactory sense of resolution. That's why the blues "sounds like a worried mind."

    Exactly! Have you ever noticed that a lot of really traditional delta type blues the guitarist will end the song by really emphasizing the flat seventh of the I chord? Lightnin' Hopkins does that a lot for one. Man it sounds good, but so troubled, as if the song is over but I'm still not at peace...

  5. #4

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    Okay, so something in this thread got me curious and lead me to a revelation.

    This is probably common knowledge, but after figuring it out, I'm pleased with myself anyway.

    For my discovery (as inspired by this thread) I dissected a Blues in E.

    E Mixolydian is the V of A Ionian ("we know!")

    Anyhow, I took the notes of the three chords from a basic 12 bar I IV V blues prog, considering each chord as a Mixolydian, and its own key.

    Mixolydian formula: 1 2 3 4 5 6 b7

    E Mix: E F# G# A B C# D
    A Mix: A B C# D E F# G
    B Mix: B C# D# E F# G# A

    the point of writing all of these notes down was to see what notes all three mixolydian scales had in common. The answer is this:

    E F# A B C# scratching my head, I re-arranged them. A being the I of E Mix, I ordered them in that fashion, which gives me: A B C# E F#

    A B C# E F# are the notes in A Major Pentatonic.

    re-rearranged like so:

    F# A B C# E gives F# Minor Pentatonic.

    If anyone cares to elaborate on what I've discovered and educate me further on the subject, I am all ears.

    .r

  6. #5

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    Cool observation Raylien. Indeed you can play an A pentatonic (F# minor pentatonic) over all of the blues changes in E.

    Also of interest, would be to compose a scale using all of the notes from the 3 mixolydian scales which gives us:

    E-F#-G-G#-A-B-C#-D-D#-E.

    Kind of a half blues scale/half be-bop dominant scale.

    john

  7. #6

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    Quote Originally Posted by John Curran
    Cool observation Raylien. Indeed you can play an A pentatonic (F# minor pentatonic) over all of the blues changes in E.

    Also of interest, would be to compose a scale using all of the notes from the 3 mixolydian scales which gives us:

    E-F#-G-G#-A-B-C#-D-D#-E.

    Kind of a half blues scale/half be-bop dominant scale.

    john
    Ah, of course, the ole Enneatonic scale

    Interesting idea.

    I'm curious now, and will throw a I IV V on my looping pedal and see how this new scale sounds.
    Last edited by Raylien; 12-09-2008 at 03:26 PM.

  8. #7

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    Hey, whaddyea know?!

    Here's a Wikipedia description of Blues Scales: Blues scale - Wikipedia, the free encyclopedia

    The third scale on the page is Enneatonic:

    C D Eb E F G A Bb B

    the spaces between these notes is this:

    C 2 D b2 Eb b2 E b2 F 2 G 2 A b2 Bb b2 B --> b2 C

    the scale mentioned above (doing the same to the example in E) gives us

    E 2 F# b2 B b2 G# b2 A 2 B 2 C# b2 D b2 D# --> b2 E

    The relationship is the same.

    So, this explains where there example came from, eh? How cool.

    In conclusion, the Enneatonic Blues Scale appears to be:

    1 2 b3 3 4 5 6 b7 7

    Seems funny how the "Blues note" (a b5) is not in this scale...

    So, where does the hexatonic blues scale come from, anyhow? (minor pentatonic + b5)

  9. #8

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    Intervals are the building blocks of all things harmonic.

    I attached a chart looking at the function of each note of the
    chromatic scale in relation to I IV V in E.

    I hope this can be helpful in understanding scale choices.

  10. #9

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    I think that 12 bar blues are in one key; maybe there's a modal element rather than the traditional view of major and minor, but it still is a I-IV-V-I no matter how you look at it.

    Sailor

  11. #10
    Stringbean Guest
    Quote Originally Posted by Raylien
    E F# A B C# scratching my head, I re-arranged them. A being the I of E Mix, I ordered them in that fashion, which gives me: A B C# E F#

    A B C# E F# are the notes in A Major Pentatonic.

    re-rearranged like so:

    F# A B C# E gives F# Minor Pentatonic.

    .r
    This is cool, I'm hearing it....thanks man

  12. #11

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    12 bar blues 2 measures of e ,2 of a ,4 of e ,4 of a , half measure of e minor,halfe measure of f#minor, halfe measure of g#minor, half measure of g minor , i measure b7 ,1 measure a7, i measure e major ,and a big measure of b7 --- 3 keys -e -g-and d.-
    Last edited by jimmy; 01-05-2009 at 09:08 PM.

  13. #12

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    Ok, so I am a bit confused now. I am currently learning this 12 bar blues, and from what I see here, in a 12 bar blues, I can play A major blues/F# minor blues.. But it also sounds right to play E minor blues, and it also sounds right to play E major blues. I can even mix them up and still it sounds fine! (ok... so not all the time).. Then someone said that you can also consider them as a V7 of some key. (E7 is V7 of A, A7 is V7 of D, B7 is V7 of E.)

    Are these all valid? Are my statements above correct? Are there any theories set on this, or at this point is it "do what pleases your ear" thing? Any thoughts? Are there too many questions?

  14. #13

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    Quote Originally Posted by rjtorres
    Ok, so I am a bit confused now. I am currently learning this 12 bar blues, and from what I see here, in a 12 bar blues, I can play A major blues/F# minor blues.. But it also sounds right to play E minor blues, and it also sounds right to play E major blues. I can even mix them up and still it sounds fine! (ok... so not all the time).. Then someone said that you can also consider them as a V7 of some key. (E7 is V7 of A, A7 is V7 of D, B7 is V7 of E.)

    Are these all valid? Are my statements above correct? Are there any theories set on this, or at this point is it "do what pleases your ear" thing? Any thoughts? Are there too many questions?
    Ok, I tried playing the A7 over an 12 bar blues progression, but it doesn't seem to fit.. any thoughts?

  15. #14

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    Dominants are tension chords, so you have a lot of note options to play over them. Look at the jazz aproach to the dominants, ask any random person how many scales he knows how to apply over the dominant chords.
    So yes all the options are right.

    Saw you posted as I was typing this. If you mean A myxolydian with intervals 1 2 3 4 5 6 b7 1, playing that all the way through will sound off, play Emyxo during E7 A myxo during A etc.

    There are many aproaches to blues, traditionalists will say over E blues prog you play E minor pentatonic, but if you look here, many people have many thoughts.

    If you are just starting out and learning the blues as a building block ignore all those ideas for now and simply play pentatonic. The function of learning the blues in your building is phrasing. No worrying about changes or a lot of notes, just simple playing to learn how to phrase yourself.
    Last edited by Joe Dalton; 02-20-2009 at 04:04 AM. Reason: side note

  16. #15

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    Quote Originally Posted by Joe Dalton
    Dominants are tension chords, so you have a lot of note options to play over them. Look at the jazz aproach to the dominants, ask any random person how many scales he knows how to apply over the dominant chords.
    So yes all the options are right.

    Saw you posted as I was typing this. If you mean A myxolydian with intervals 1 2 3 4 5 6 b7 1, playing that all the way through will sound off, play Emyxo during E7 A myxo during A etc.

    There are many aproaches to blues, traditionalists will say over E blues prog you play E minor pentatonic, but if you look here, many people have many thoughts.

    If you are just starting out and learning the blues as a building block ignore all those ideas for now and simply play pentatonic. The function of learning the blues in your building is phrasing. No worrying about changes or a lot of notes, just simple playing to learn how to phrase yourself.
    Thanks Joe for the comment!

    However, let me rephrase my earlier comment - I am currently expanding my knowledge over the 12 bar blues. I've been practicing blues way before, and was always stuck with the BB King-like lines. Eventually when you listen to enough jazz, you'd find that E minor blues get boring. I hear a lot of things that jazz guitarists do, but can never figure out why it happened, so what I can only do is to simply imitate (ok - so maybe I don't spend a lot of time with theory as compared to playing.) But the problem is, most of the time I find myself hitting the wrong notes, especially when trying to expand lines that I've just heard.

    But anyway, I guess, the "all approaches are possible to scales applicable to dominant" pretty much answers my question - I thought there was some mystery behind it.. Now all I have to do is learn all the scales applicable to dominants.


    BTW - I mean A Major Pentatonic with a blues note (#2), and not A7. I apologize for that.

  17. #16
    Short answer to original question: Yes, technically a 12 bar blues is in 3 keys. No dom7 chord exists in any 2 keys. G7 is always technically the 5 chord for C major, in diatonic western music.

    However, the nature of blues is to play notes that don't fit over these chords in order to convey tension. The blue notes are the flat 3 and flat 5, and sound most clearly blue when they clash with the chord over which they are being played. If you play nothing but major pentatonics or mixolydian scales over the corresponding chords, it won't sound like the blues, or at least not much.

    SO, with a framework that is basically always tension, does our ear hear 3 keys in a 12 bar blues? No. That's why you can sound good on a straight 12 bar blues just playing the tonic blues scale. You'll be more interesting if you add other stuff, and that's really a rock approach and not a jazz blues, but you can do it. However, when you're playing a jazz standard, and you hit that ii-V, it is a temporary key change and you do have to respect it! Hope I didn't add too much to your confusion.