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Chords within the key...

Discussion in 'General Instruction [BG]' started by cafepurgatory, Jul 14, 2001.


  1. Alright, I know I learned this 10 years ago in my high school music theory class, but I've had a lot of liquor since then. Sue me. ;)

    In a given key, for the sake of simplicity we'll go with the ever popular C Major, the chords would be (on a BASIC level, at least)

    Cmaj7
    Dmin7
    Emin7
    Fmaj7
    G7
    Amin7
    Bdim

    First of all, is this correct?

    If so, then in the relative minor (A Minor) would the chords be arranged like this?

    Amin7
    Bdim
    Cmaj7
    Dmin7
    Emin7
    Fmaj7
    G7

    I know this is probably a bonehead question that I shouldn't even need to ask, but hey, I do. :D
     
  2. Phil Smith

    Phil Smith Mr Sumisu 2 U

    May 30, 2000
    Peoples Republic of Brooklyn
    Creator of: iGigBook for Android/iOS
    That looks correct.

    The B is half diminished i.e. Bmin7b5
     
  3. Ok. Thanks!

    Please explain, though, half diminished vs diminished.

    ???? (slightly confuzzled over that one)
     
  4. Diminished = B-D-F-Ab (the seventh is diminished, or double flat).

    Half-diminished = B-D-F-A (seventh is flat).

    You shouldn't say half-diminished, the proper term is "minor seventh, flat five".

    When you get into a minor key, some chords change. Am becomes Am maj7 (A-C-E-G#)and Em is E7, the latter being the dominant chord. It's also common to see the G7 having is 3rd sucked up. It becomes a G7 sus4.
     
  5. Groovy. I appreciate it Eric. :)
     
  6. stephanie

    stephanie

    Nov 14, 2000
    Scranton, PA
    Just a little confused here on how a half-diminished chord is made up.

    I mean, I know it's like what you said. But what scale is it derived from?

    Does it come from a regular W-H or H-W diminished scale or, being it is equal to a m6, does it come from a m6 scale? Or is it just simply the R, b3, b5, and b7 of the major scale?

    Sorry, does this make any sense? LOL.

    I'll go now.

    Cheers,

    ~stephanie
     
  7. Pacman

    Pacman Layin' Down Time Staff Member Gold Supporting Member

    Apr 1, 2000
    Omaha, Nebraska
    Endorsing Artist: Roscoe Guitars, DR Strings, Aguilar Amplification
    It's derived from the locrian mode of the major scale. It's called half diminished because though it has the flat 5th associated with the dim chord, the 7th degree is only lowered once, rather that the doubly lowerd 7th.
     
  8. jazzbo

    jazzbo

    Aug 25, 2000
    San Francisco, CA
    Most jazz cats I've met say "min7b5" while the classical guys tend toward "half-diminished." That's just been my experience.
     
  9. Phil Smith

    Phil Smith Mr Sumisu 2 U

    May 30, 2000
    Peoples Republic of Brooklyn
    Creator of: iGigBook for Android/iOS
    Using the scale of C major and starting on the seventh note(locrian) of the scale i.e. B, the corresponding chord would be B D F A or a minor chord with a minor seventh and a flatted 5th. The intervals are a minor 3rd, minor 3rd, major 3rd, whereas diminished would be minor 3rd, minor 3rd, minor 3rd or minor 3rds stacked on top of one another i.e. B D F Ab.
     
  10. stephanie

    stephanie

    Nov 14, 2000
    Scranton, PA
    Thanks Pacman and Phil. I understand that better.

    I guess I won't go into asking why the B is automatically a minor chord. It's late and I'm sure I'll figure it out after I get some sleep. LOL. :D

    Oh wait...maybe I'm answering my own question here: Is it because the 7th of the scale is diminished (tho half-diminished)?

    Oh well. I should learn not to ask things when I'm dead-tired. I apologize.

    Thanks again,

    ~stephanie
     
  11. Phil Smith

    Phil Smith Mr Sumisu 2 U

    May 30, 2000
    Peoples Republic of Brooklyn
    Creator of: iGigBook for Android/iOS
    We start with the C major scale:

    C D E F G A B C

    The locrian mode would be:

    B C D E F G A B

    If we take the Root, 3rd, 5th, and 7th of this mode
    we get B (min 3rd) D (min 3rd) F (maj 3rd) A.

    The easiest way to work this out is on a piano or keyboard using the C major scale i.e. all the white keys. Play the first 7th chord starting on C, which will be C E G B or C Major 7, arpegiate it, meaning play one note at a time, then play all the notes at once. Do the same thing starting with D, E, etc...