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The Evolving Bassist

Discussion in 'Music [DB]' started by pfactor2, Sep 6, 2008.


  1. pfactor2

    pfactor2

    Jun 18, 2008
    Page 104. Explaination on 102, ll-V cycle of fifths starting on sharp four of the chord. I dont get it. First off it looks like cycle of forths and second isnt sharp 4 the altered fourth mode? Please (simply) explain the explanation. Thanks
     
  2. bjm

    bjm

    Jan 2, 2008
    San Jose, CA
    OK, I can see why this is a little confusing. I give it a go.

    First, note that this exercise number 2 is rhythm changes in Bb. You can tell by comparing bars 3-8 to the previous exercise and see that they are very similar. Only bars 1 and 2 are really different.

    Now, in the key of Bb major, the 4th degree of the scale is Eb, so the #4 degree of the scale is E natural. The ii-V progression (actually, "cadence") in Eb is F#mi7 then B7. That's where the first two chords come from.

    A good question is, "why/how can these chords be used instead of the "normal" rhythm changes?"

    It is just a "tritone substitution" that you will commonly find in jazz tunes. Notice that in Bb major, the ii chord is Cmin7 (C-Eb-G-Bb) and the V7 chord is F7 (F-A-C-Eb), whereas in E major the ii chord is F#min7 (F#-A#-C#-E) and the V7 chord is B7 (B-D#-F#-A).

    Let's compare these DOMINANT of chords:

    F7 vs. B7
    ---------------------
    F-A-C-Eb
    vs.
    B-D#-F-A (for convenience, write this as B-Eb-F-A)

    Notice that there is only one different note (B vs. C)! But most importantly, the 3rd and 5th of each chord is a tritone (aug 4th) interval. This is the important quality that makes the chord dominant and it wants to resolve down a fifth (up a fourth), which is exactly what it does in the progression you are analyzing (it goes to Emin). You can pretty much always sub any DOMINANT with another DOMINANT that is an augmented fourth away.

    Then it does the same thing again to get to Dmin, where it "catches up" with the original progression. Subbing one series of chords for another in this particular way (i.e. from around the circle of fourths) is called "back cycling" and is pretty common.

    Hope that helps.

    -jeff
     
  3. I assume that was just a little misprint, but generally dom7's have a perfect 5th, and I believe this is the case with the book. So it should be
    B D# F# A. The explanation is good, but the tritone sub thing seems to be way over explained and I think people (at least I did) seem to be scared of it (not understanding it) when in reality its very simple. It works because of the 3rd and 7th like you said. They're the same, just flipped. The real trick is to use it appropriatley and not overdo it.
     
  4. bjm

    bjm

    Jan 2, 2008
    San Jose, CA
    Yes, I mistyped the F# as F.

    I was intentionally longwinded about it since the original asker of the question asked for simple and I took that to mean "don't leave anything out". One might ask why we can sub one for the other, and your answer is simple:

    The 3rd and 7th are the same, so you can sub it.

    It's all good.

    -jeff
     
  5. pfactor2

    pfactor2

    Jun 18, 2008
    thanks for helping, I understand the theory behind the progression. I've heard it and played it and now understand i have more work to do.
     
  6. pfactor2

    pfactor2

    Jun 18, 2008
    Could this be the case of egg before the chicken. I totally see how the cycle resolves. Did the original be-bop players say check this out, we will start on F# and do the cycle and resolve on Bb and then in the ah hah moment say really it starts on the ii-v sharp 4 of the chord OR visa versa??
     
  7. pfactor2

    pfactor2

    Jun 18, 2008
    Could this be the case of egg before the chicken. I totally see how the cycle resolves. Did the original be-bop players say check this out, we will start on F# and do the cycle and resolve on Bb and then in the ah hah moment say really it starts on the ii-v sharp 4 of the chord OR visa versa??
     
  8. bjm

    bjm

    Jan 2, 2008
    San Jose, CA
    It's hard to say what someone else was thinking, but if you look at the circle of fourths and consider each note a key center, you can see that it hits every key center. Therefore, you can always get from any chord/key to any other chord/key by backcycling, i.e. by plugging in a string of ii-V's until you land on the chord you need.

    BTW, this is often done as a never-ending circle to vamp, say, until a performer starts singing or talking as in a musical.
     

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