From: sumrn@dssv01.crd.ge.com (Robert N. Sum)
Newsgroups: alt.guitar,alt.guitar.tab
Subject: Re: What is the 12 bar blues rule?
Keywords: blues progression, 12 bar blues
Date: 27 Aug 92 13:05:42 GMT
Reply-To: sumrn@crd.ge.com
Followup-To: alt.guitar
Organization: GE R&D, DICE Program

In article <sbb1.714878439@Ra.MsState.Edu>, sbb1@Ra.MsState.Edu (Shay B.
Berthelson) writes:
|>What is the rule that when speaking of blues people mention the 
|>standard twelve bar.  Please help.  Also any one have any good sounding 
|>easy to learn riffs, not neccessarily blues.
|>
|>
|>Thanks
|>Shay B.
|>
|>--
|>**********************************************************************
*********
|>** Shay B. Berthelson ******   Don't call me WHITE
***************************
|>** sbb1@Ra.MsState.EDU *****   I am Danish American
**************************
|>**********************************************************************
*********
             
The 12-bar blues is the harmonic progression that has come to be the most
common for blues tunes.  There are many, many variations.  (For those
who may have seen my recent posting [if it made it to the world] on
changing keys, some of the introductory material is the same.  You may
wish to skip a page or so.)

  I assume that the reader is familiar with keys and scales,
particularly major and minor.

  I will assume some familiarity with these few chord types (all
examples have root note of C, but not necessarily in key of C):
  
  major written M (e.g., CM) or nothing (e.g., C) with notes C E G,
  minor written m (Cm) with notes C Eb G,
  diminished written o (Co) with notes C Eb Gb,
  dominant 7th written 7 (C7) with notes C E G Bb,
  major 7th written M7 (CM7) with notes C E G B, and
  minor 7th written m7 with notes C Eb G Bb.

There are others that are useful, but these will do.  I also should make
apparent the use of roman numerals for chords within a scale.  In a
major key (with C as an example):

  C     D     E     F     G     A     B     C
  I     ii    iii   IV    V     vi    vii^o I

where UPPER case represent major chords and lower case indicate minor
chords and the superscript o indicates diminished chords.  (Actually,
you can get a bit pickier, but this will do for now.)  When the seventh
is used in this notation the seventh is assumed to be the one that would
occur in the current key e.g., I7 here is CM7 while V7 is G7.
We're using two different shorthands here.

The simplest 12-bar blues that I've seen has the following pattern:

I    I    I    I    IV    IV    I    I    V    V    I    I
C    C    C    C    F     F     C    C    G    G    C    C

where each chord occupies an entire measure.  The variation used in
many rock tunes (particulary early ones like "Rock Around the Clock")
use a IV in place of the last V chord:

I    I    I    I    IV    IV    I    I    V    IV   I    I
C    C    C    C    F     F     C    C    G    F    C    C

A more "jazz-flavored" version uses a ii in place of the first V:

I    I    I    I    IV    IV    I    I    ii   V    I    I
C    C    C    C    F     F     C    C    Dm   G    C    C

(Once in a great while you might see a IV in place of the ii, but this
runs the risk of sounding too "classical.")

The next common thing to do is to make all the chords either dominant seventh
or minor seventh chords.  At this point the roman numeral system becomes a
mess so I'll skip it and assume that the player can add the sevenths
appropriately.

Sometimes IV is used for the second I chord:

I    IV   I    I    IV    IV    I    I    ii   V    I    I
C    F    C    C    F     F     C    C    Dm   G    C    C

Finally (for this treatise), one sometimes substitutes chords in other
parts of the progression to add things such as "turn-arounds."  (The |
indicate the ends of measures.)

I    |IV   |I    |I    |IV    |IV    |I    |I    |ii   |V    |I    |ii V |
C    |F    |C    |C    |F     |F     |C    |C    |Dm   |G    |C    |Dm G |

Have fun,

  Bob

==
  sumrn@crd.ge.com

  Robert Sum
  G.E. Corp. R. & D.
  P.O. Box 8, Rm. KW-C277
  Schenectady, NY 12301

  Tel. (518) 387-7696

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