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B diminished

Discussion in 'General Instruction [BG]' started by DarkArwen, Apr 26, 2010.

  1. DarkArwen


    Oct 29, 2009
    Yes, I searched and I am sorry if I missed the answer to my question already.
    So major pentatonic is 1-2-3-5-6
    Minor pentatonic is 1-3-4-5-7
    What is the diminished pentatonic? Specifically for B dim.
  2. mambo4


    Jun 9, 2006
    In a strict sense there's no such thing.

    First, I'll cut and paste my words from another thread:
    Let's define things in terms of the major scale:
    Maj scale: 1 2 3 4 5 6 7
    Maj pentatonic: 1 2 3 5 6

    Min scale: 1 2 b3 4 5 b6 b7
    Min pentatonic 1 b3 4 5 b7

    You probably know that the minor pent is the same notes as the major pent , just started on the 6th instead of the 1.
    Usually, "pentatonic scale" refers to this exact sequence of whole steps and 3rds as derived from the major scale.

    So in the sense described above there is no "diminished pentatonic scale"

    technically you can string together any 5 notes and declare them to be a pentatonic scale, if you want. But how you do it depends highly on the context you want to do it

    so to construct a 5 note sequence that works over a diminished chord, you need to make sure it uses the chord tones.
    The primary harmonic characteristic of a diminished chord (triad) is a flat 3rd and flat 5th , so you could try a minor pent with a flat 5th:

    Min pentatonic 1 b3 4 5 b7
    "Dim" pentatonic 1 b3 4 b5 b7

    realize that diminished chords have a variety of flavors that may or may not work with this.

    Dim triad chord: 1 b3 b5
    min7b5 chord: 1 b3 b5 b7
    min 7 chord: 1 b3 b5 bb7

    the double flat 7th in a minor 7th chord is outside of the above "diminished pentatonic" scale, so you could even try to replace the b7 with the bb7.

    Seem like too much theory for your purposes? It probably is.

    I assume you want to either:
    1.) come up with something to play over a diminished chord
    2.) Explore serious riffage with a diminished flavor
    3.) Are trying to come up with a bass line to support someone else's diminished flavor riffage.

    If #1, then just play the chord tones and let your ear choose the passing tones you use
    If #2 just use the diminished scale or locirian mode and your ear, or minor pent with a b5
    If # 3 you are most likely stuck following the riff, or at least doubling the most emphasized notes...
  3. +1 to what mambo4 said.

    Want to make any scale a pentatonic......
    If it's a Major scale omit the 4 and 7.
    If it's a Minor scale omit the 2 and 6.

    Bdim would be the diminished scale, which also means it's a minor scale - so, use the minor scale - with it's b3, b6 and b7 - then flat the 2 and 5 to get the diminished taken care of, then omit the 2 and 6 to turn it into a pentatonic.

    Shifting gears --- Letting this logic flow -- Add a #4 or b5 to the minor pentatonic and you've got the blues scale. Take the major 7 note scale and flat the 7th and you've produced Mixolydian, sharp the 4th and you made Lydian, etc. Just take it one step at a time and figure out what you want to accomplish. Start with a known - change a note and you've built something new.

    Again as mambo4 pointed out you can get to the diminished pentatonic, however you are probably better off ".... just using the diminished scale or locirian mode - or minor pent with a b5 and let your ear decide."

    Good luck.
  4. DarkArwen


    Oct 29, 2009
    Lots of theory, but I need to know these things! To be honest, I was seeing if I could play B dim under a Fmin (played by the guitar) without it it crashing into the C. So, I am guessing the C will crash. I will have to come up with something else. Thanks alot!!!
  5. No need to guess. Go here:
    http://www.riddleworks.com/modalharm3.html See what it says about what chord vamp to use with Locrian or the diminished mode.
    Give some thought to a modal vamp (chords) of Bm7b5 and Cmaj7 under B Locrian. See how that sounds to you.

    Like notes in the melody line and chord vamp seem to work fine. http://www.looknohands.com/chordhouse/guitar/index_rb.html may be something you can use. Call up the Bm7-5 chord and the Cmaj7 chord to see what notes they contain, then compare that with the B diminished mode aka B Locrian.

    Good luck.
  6. SanDiegoHarry

    SanDiegoHarry Banned Supporting Member

    Aug 11, 2008
    San Diego, CA
    I'm no theory expert, but I took years of piano - and they always said " A flat 5 is diminished; A sharp 5 is Augmented".

    So just flat that 5 and BAM - Diminished. Like the smarter guys than me said above.
  7. BassyBill

    BassyBill The smooth moderator... Gold Supporting Member

    Mar 12, 2005
    West Midlands UK
    A diminished scale is constructed by using alternate semitone and tone intervals. Starting on B, we could have (representing all notes as either naturals or single flats for ease of reading here):

    B, C, D, Eb, F, Gb, Ab, A, B


    B, Db, D, E, F, G, Ab, Bb, B

    Notice the following:

    a) These scales both include one extra note compared to standard modes of the major scale (Ionian, Dorian and so on).
    b) The notes common to both are B, D, F, Ab (B) and the interval between any adjacent two of these notes is always 3 semitones / a minor 3rd.
    c) These four notes would make up the chords B dim, D dim, F dim or Ab dim.
    d) The B Locrian mode (B, C, D, E, F, G, B) doesn't include the very important Ab note and so it is not usually the best choice for playing over a diminished chord.

    You could choose either of the scales as a basis for playing over a B dim chord, depending on the musical context. Easiest note choice would be just to use the four notes contained in both scales - B, D, F, Ab.

    As always, try experimenting around with this info and see what you think sounds good to you.

  8. benc


    Jan 29, 2002
    Houston, TX
    Mambo4, MalcomAmos, BigOldHarry and Bassybill posted some great, useful, educational and theoretically-correct stuff above. DarkArwen, you didn't mention it in your original post so I'm sure they didn't realize you were wanting to play Bdim over an Fm chord.

    I'm not sure what you meant by "crashing into the C" and "the C will crash." I think you meant C would CLASH with the Fm chord. Not true. Playing a "C" note over an Fm chord is fine. Hell, it's the fifth of the chord - about as consonant as it gets. There are much worse notes to play over Fm. It's all about context, though. Horn players know any note over any chord is fair game as long as it's played in the right place and at the right time.

    We bass players are counted on to keep it simple, though. It's our job to outline the harmony and let the soloists expound on it.

    That said, playing B Locrian (all white keys - BCDEFA) over an Fm chord is probably not a good idea. C and F are good notes for sure. D is probably ok too, depending on the context of the Fm chord. "A" natural is about the worst note you could play over Fm. B (#4) and E (#7) are likely bad note choices, too.

    Again, it's all about context, though. DarkArwen, what does the Fm resolve to? What key is the song in? How many beats or measures is the Fm chord held? What kind of song is it?

    Yeah, what Bassybill said. Stacking minor thirds starting on B kinda makes the diminished Pentatonic scale you were looking for (even though it's only 4 notes). That "scale" might actually work ok over Fm. If I was hell-bent to play Bdim over Fm, I would play the stacked minor thirds arpeggio. (I wouldn't play B natural on beat one of an Fm measure, though. That wouldn't sound so hot. Better to start on Ab, an Fm chord tone).

    The half-note-whole-note scales that Bassybill mentioned are great to play over a diminished chord. If you choose to play one of those on Bdim over Fm, I would suggest the one that starts with a whole step - the one without A natural. Again, A natural is the worst note you can play over Fm.

    I'll stop now. I've had enough wine to believe I know what the hell I'm talking about.
  9. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    boy, you guys come up with some wordy ways of saying 1-b3-b5-6 or B-D-F-G#!

    but ultimately Dark, once you digest the info they gave you, you'll get some really good stuff that will help you more than simply giving you the scale degrees.
  10. Chris K

    Chris K

    May 3, 2009
    Gorinchem,The Netherlands
    Partner: Otentic Guitars
    Wow Jim, I guess you just got this close to a dim chord.
  11. DarkArwen


    Oct 29, 2009
    @jimmy. I was calling it Ab, is there some kind of reason it's G# instead?
    It's a song I wrote. The Fm goes to Bdim. Song is in Cmin. The reason for the issue is the guitarist is having some trouble shifting from Fm to Bdim (and also Gmin to Bdim)

    I was trying to find a way around the issue w/o abandoning the Bdim, which I guess I could do, but the entire song was written as an excuse to play Bdim. I was wondering if maybe she could keep playing the Fmin and I could just arppegiate the Bdim, which from what I am gathering may work with the Fmin, but not at all with the Gmin.
    I'm singing when it goes Fmin to Bdim but not Gmin to be Dim, so I can change the Gmin. It's the Fmin I wonder about.
    Thank you guys so much. This is a lot to digest, but I'm sure it will make my life a lot better to really internalize the whole modes things.
    Thanks again.
  12. DarkArwen


    Oct 29, 2009
    and speaking of which?? Why can't I play Ab since it's in Fmin and Bdim7? Or was I supposed to search for that answer?
  13. A new guitar player...??? :D ;)

  14. Bdim is not your problem - the Fm chord is. Keep the Bdim aka B Locrian. Which gives you:

    B Locrian
    intervals: 1,b2,b3,4,b5,b6,b7
    half-steps: 1-2-2-1-2-2-2
    notes: B,C,D,E,F,G,A --- sure looks like C Major to me - you suppose a Cmaj7 chord will work in here somewhere?

    Then use a vamp of Bm7b5 and Cmaj7. Look at the notes in these chords. These chords have the same notes as B Locrian, which means they fit and will sound good.
    a.k.a.: B°7, B½dim, B½dim7, Bm(b7), Bminor7b5
    intervals: 1,b3,b5,b7
    half-steps: 3-3-4
    notes: B,D,F,A

    C maj7
    a.k.a.: CMaj7, CM7
    intervals: 1,3,5,7
    half-steps: 4-3-4
    notes: C,E,G,B

    Now draw your melody notes from the chord's notes, i.e. when over the Bm7b5 chord use B, D, F, A in your melodic phrases. And then when over the Cmaj7 use C, E, G, B in your melodic phrases. Every one of those notes can be found in B Locrian. Not necessary to use arpeggios, just make up melodic phrases - couple of passing notes not found in the chord as long as they are in the scale/mode is OK - if not on the 1st and 3rd beat. It's here that pentatonics over the chord is great for gathering melodic phrases as the pentatonic will give you three chord tones and two safe passing notes. Give pentatonics a try, much easier than modes, and that diminished mode --- do those much later.

    Cheat --- use http://www.looknohands.com/chordhouse/guitar/index_rb.html and find what chords have the same notes your scale/mode have. If you do that it will work every time.

    With modes think vamps. Vamps sustain the modal mood. Chord progressions have a tendency of sustaining the scale's tonal center, in this case C Major.

    If you gotta have that F chord -- change it to F (Major) and it will fit with the B Locrian notes.
    F Major
    a.k.a.: F, FMaj, FM
    intervals: 1,3,5
    half-steps: 4-3
    notes: F,A,C

    Now it's your song if you like Bdim and Fm - fine with me. If it sounds good to you that's all that matters.

    Have fun.
  15. DarkArwen


    Oct 29, 2009
    @planetearth. HAHA, nah she's great. We are currently a trio, and I am seeing how we could def use a proper rhthym guitar though. Sides, they should have gotten rid of me long ago. Lots of better bassists out there than me.
  16. mambo4


    Jun 9, 2006
    If the Key is Cmin (of some kind)
    and you are using a B dim chord
    it implies that you are using C harmonic minor
    Which, if you are a key Nazi, makes the Gmin chord a G7.

    but you probably just like the sound of the B dim and don't care.

    If the B dim is simply a result of you using a B natural in your bass line,
    the guitarist can probably just use a G7 every where there is a B dim...
    since B dim triad with a G in its root = G7...
    and you can hold down the B natural with your bass.

    and if your guitarist can't play G7, you're in trouble :)
  17. ryco


    Apr 24, 2005
    half dim: 1 b2 b3 b5 b7 = B C D F A
    full dim: 1 2 b3 b5 bb7 = B C# D F Ab
  18. ;)

    Seriously tho: Have you tried voice leading the two?


  19. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    absolutely! if we're in the key of B, the scale is B-C#-D#-E-F#-G#-A#-B, no flats, only sharps. i get a lot of charts on gigs where the arranger mixes flats into a key where sharps should be used, and it drives me insane! so i always do my best not to imappropriately mix the two.

    another key that drives me nuts is F#. Some call it Gb, but compare the F# major scale to the Gb major scale and tell me which is easier to write/decipher:



    ok, not a big huge difference, but when you read F# charts, it's a lot easier to remember to play a B that's on the B line than remembering that a note on the C space should be flat. at least that's the way i see it. as always, ymmv.
  20. JeffBerlin

    JeffBerlin Guest

    Jan 10, 2009

    It's supposed to be F natural, not Fb in the Gb scale.

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