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Theory ?'s: key sigs/chord scales/accidentals

Discussion in 'General Instruction [BG]' started by emor, Nov 15, 2004.


  1. emor

    emor

    May 16, 2004
    kcmo
    This may seem like a dumb and obvious question, but bear with me please.

    I am trying to figure out the relationship of key signatures to chords within a piece.

    I will use as an example a line adapted from a Patrick Pfeiffer lesson on activebass.com.

    It was in TAB form; this is how I notated it (more about that in a minute).

    It is a vamp on C7 (right?).

    Now, suppose one were to use this riff on a I7-IV7-V7 progression (C7-F7-G7). If I remember correctly, a dominant 7th chord = mixolydian mode (Major scale with b7).

    The tonal center is "C" (key signature=no sharps or flats); however, C7 has Bb, F7 has Bb and Eb.

    So, question #1: What is the purpose of the key signature?--it seems to apply mainly to establishing the tonal center of the "head" (melody line), and not so much with the chord progression.

    Question #2: When you have passing tones, as in the example given, what is the theoretically correct way to notate? (sharp or flat?). For example in the C7 figure, I have already used a flat (Bb=b7 of C), so I used a Gb rather than F#; but moving up chromatically from Bb to C, should it be a B natural or Cb (which seems awkward); but if I used a B natural here, in the G7 figure, wouldn't it be an F# rather than Gb (as I have written)?

    Thanks,
    emor
     
  2. emor

    emor

    May 16, 2004
    kcmo

    O.K., upon review, that's kind of stupid--it establishes the tonal center of the chord progression, as well, but the notes within the chords are different than those in the key signature.
     
  3. emor

    emor

    May 16, 2004
    kcmo
    I just spent the better part of the last couple of hours doing searches and going to various music theory links.


    (sigh...)



    What I need is a good teacher.
     
  4. Bassart1

    Bassart1 Guest

    Jun 26, 2003
    Materials In Tonal Music by Paul O. Harder

    Volumes I & II


    That'll sort you out.
     
  5. What is the theoretically correct way to notate?
    In Theory the key signatures go by the order of sharps and flats
    ie F-C-G-D-A-E-B for sharps

    B-E-A-D-G-C-F for flats

    So In your example G7 we know that G7 is from Cmaj
    ie From our modes in C maj we get
    I-Cmaj
    II-D dorian
    III-E phygian
    IV-F Lydian
    V-G mixolydian ..... etc
    So G7 is the V ( fifth ) mode of Cmajor so therefore you would use B natural not F# because the key signature for Cmaj has no sharps or flats
    However If G7 was Gmaj then you would use F# because in Gmajor it has one sharp which is of course F
    So the key signature's purpose is to group if you like all its related chords in it's appropiate key
    Does that help you out a bit
    There's some other guys who may hopefully explain in good detail
    Anyway a Teacher will help
     
  6. emor

    emor

    May 16, 2004
    kcmo
    In Theory the key signatures go by the order of sharps and flats
    ie F-C-G-D-A-E-B for sharps

    B-E-A-D-G-C-F for flats



    O.K., I know that.

    The next part about the modes I'm not following.
    If you have a progression that is C7-F7-G7, wouldn't you be playing:
    C mixolydian (C D E F G A Bb C)
    F mixolydian (F G A Bb C D Eb F)
    G mixolydian (G A B C D E F G)
    ?

    My question about the passing tones has to do with notes not found in the key signature (accidentals) or in the chord scales. Since the example is in the Key of C (no sharps or flats), I assume that the B natural in bar 2 and 4, and the E natural in bar 4 are correct.
    But how about the notes (circled in red) In bar 2 and 6? Are they Gb or F#, Db or C#? And how is it determined?
     
  7. WillPlay4Food

    WillPlay4Food Now With More Metal! Staff Member Supporting Member

    Apr 9, 2002
    Orbiting HQ
    I think the notes should be flatted. My reasoning is, look at your scales. If you used A# instead of Bb in C Mixo for example, that would make the note a sharped 6th, not a flatted 7th. I know, they are the same note in that the sound of a Bb == the sound of an A#. BUT, in the scale you derive the chord, the Bb is a flatted 7th (which is what you need for a I7 chord).

    So go with the 7th note, then flat it. In G Mixo you're flatting the F# so you get F. In F Mixo, E is the 7th note in the scale so Eb would == flatted 7th. In C Mixo, B is the 7th, so flat the B to get Bb.

    Does this make sense to you?
     
  8. Howard K

    Howard K

    Feb 14, 2002
    UK
    You know, I'm not sure it actually matters all that much? (but then I'm not the greatest theory head in the world!)

    Generally speaking, I'd avoid using Cb, or E#.. and try to make it consistant, perhaps using #s when the line ascends and b's when it descends?

    If there are more strict rules I'm sure someone here can explain better than I... I'd be intersted to learn too.. try posting the same Q in 'music theory' on DB
     
  9. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    In the C7 sequence, I would write it F#, not Gb, then keep the Bb and B as you have them.

    In the F7 sequence, I would *definitely* write B natural, not Cb, then keep Eb and E as you have them.

    In the G7, I would write C# instead of Db, and F# instead of Gb.

    As for your more general question about there being notes in the riffs that aren't accounted for in the key signature, you've stumbled across a little secret (probably not much of a secret) about much of our popular music, which is that a lot of such music is not perfectly accounted for by standard major-minor theory. In "straight" theory (for lack of a better term), you wouldn't generally have a 7 chord as your I, though that's perfectly acceptable in blues. A I7 in a straight setting is more likely to be functioning not as a tonic but as a V7 of the IV.

    Often, the use of a key signature for certain types of popular music is more an indicator of the tonal center of the piece, rather than a strict guide to key as legit theory would have it. Thus, for a blues in D, there will often be a key signature of D major, even if you then have to use a lot of accidentals to indicate how the piece really has to be played, and even if D major, strictly understood, doesn't entirely explain what's really going on. It's kind of a convention.
     
  10. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Generally, that's not a bad basic policy that will get you acceptably through a lot of situations, though not all. Just remember that flatting an already sharped note means using a natural, not a flat, and sharping an already flatted note also means using a natural.
     
  11. Howard K

    Howard K

    Feb 14, 2002
    UK
    Yeah, I just figured it would be easier on the eye :)

    Although on reflection, if I wrote a melody Bb B C B Bb over a Bb chord I'd write it B natural both times.

    I guess it depends mostly on the chord and what the note does at the time. F# over C7 is the #11. Whereas Gb is the b5, but the natural 5 is still present in the chord... although if it's a passing tone, it's not going to be on a strong beat, so.. :crying:
     
  12. Matt Ides

    Matt Ides

    May 12, 2004
    Minneapolis, MN
    If it has a flat in front of it, then you call it ?b, a sharp in front of it, then ?#. That is the way to call the note. If it is written as Db in notation, you would not call it C#, and vice versa.

    b's and #'s are written with the key signature or temporary key or chord symbol for that measure.

    If you are in Gmaj, you would write F# (key signature for Gmaj) not Gb.
    If you are in Fmaj, you would write a Bb (key Sign again) not a Cbb or A#.

    The circle of fourths and fifths are your key to working this out.

    Hope this helps.
     
  13. Howard K

    Howard K

    Feb 14, 2002
    UK
    Respectfully, I think you missed the point, ssab67. The thread starter was asking about writing, rather than reading notation, and specifically notating a melody over a non-diatonic chord progression.
     
  14. Matt Ides

    Matt Ides

    May 12, 2004
    Minneapolis, MN
    Theory really doesn't help much here since you are using V7 chords.


    I would use Db and F# for practical matters based on the chord symbols above them and common usage.

    If you can't read what you wrote and make sense of it, where does that leave you. More confusion.

    If you want to be more technical and theory based.

    G7 (Cmaj) So use of flats and sharps is more free range (usually helps to stick to one or the other)

    F7 (Bbmaj) Would use flats.

    C7 (Fmaj) would use flats again.

    I bring this up because when you are reading and sight reading it is easier to think in flats or sharps (keys, not both at the same time).
     
  15. emor

    emor

    May 16, 2004
    kcmo
    Thanks for all the responses.
     
  16. Howard K

    Howard K

    Feb 14, 2002
    UK
    People seem to notate blues just fine?

    You have # accidentals in b keys and vice versa.

    I think it depends on the scale/chord more than the key. You wouldnt notate Gb in a melody over a C7 chord because it is a #11, not a b5 regardless of the key signeture.
     
  17. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Actually, you might do just that, depending on the context. F#/Gb doesn't necessrily always function as a #11 in the key of C. If you were playing the notes G-Gb-F, using Gb instead of F# would be IMO both permissible and preferable. If it were going the other way, you'd be more likely to use F#: F-F#-G.
     
  18. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Well, you can notate them, but as I pointed out above, you often have to use a lot of accidentals that aren't accounted for by the key signature. Having a dominant chord as your tonic isn't something that standard major-minor key theory takes account of very well.
     
  19. Howard K

    Howard K

    Feb 14, 2002
    UK
    I was saying F# functions as a #11 over a C7 chord, regardles of the key.. i.e. Gb is the flatted 5th.

    but, yes, fair point.. as a passing tone I guess it makes no difference whatsoeverl.. hang on, I think I said that a few posts ago?... blimey, I'm starting to contradict myself... I'll get my coat... :rolleyes:

    re: blues, keys, etc, yeah totally, i was just rejecting the notion that "theory wont help you here!" :D