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Thread: Diminished third issue?

  1. #1
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    Post Diminished third issue?

    I'm in a theory course at my highschool, and we were working on intervals last week. I had a question that my teacher couldn't answer so I'm looking for help here.
    Gflat. Gb, if you will. The major third is Bb. The minor third is Bbb. What is the diminished third? Can you have a triple flat?

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    Registered User bluesking's Avatar
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    I've never come across such a thing as a "diminished 3rd". Intervals are not generally termed "diminished" they are either flat or sharp (or in the case of the 3rd major/minor).

    Diatonically speaking, a "diminished 3rd" would be the same as a 2nd. This would be labelled Ab in your example.

    The only double flat interval I have seen in theory is the bb7 in a diminished 7th chord.
    Last edited by bluesking; 04-02-2010 at 12:36 AM.
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    You might check out this wikipedia article...it's going to be enharmonically equivalent to Ab. This article suggests a triple flat symbol exists; I've never seen one.
    Last edited by walternewton; 04-02-2010 at 01:28 AM.

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    Registered User Malcolm's Avatar
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    Quote Originally Posted by LRellim12 View Post
    Gflat. Gb, if you will. The major third is Bb. The minor third is Bbb. What is the diminished third? Can you have a triple flat?
    OK your answer lies here http://www.musictheory.halifax.ns.ca/10intervals.html. Way deep, beyond my caring one way or the other.

    If I read it correctly -- that Bbb -- there are other markings used.
    Last edited by Malcolm; 04-02-2010 at 02:10 AM.

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    Registered User bluesking's Avatar
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    Quote Originally Posted by walternewton View Post
    You might check out this wikipedia article...it's going to be enharmonically equivalent to Ab. This article suggests a triple flat symbol exists; I've never seen one.
    Wow, I never knew most of that. Probably in one ear and out the other for me! Thanks.
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    bitter old fool Jed's Avatar
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    Any major/minor interval (so 2nds, 3rds, 6ths, 7ths, 9ths, 13ths) can have a diminished form. As was said earlier, a diminished 3rd would be enharmonically equivalent to a major 2nd. A diminished 2nd is enharmonically equivalent to a unison. etc, etc

    The number of flats of sharps is immaterial. Sharps and flats are alterations we use to gain a "proper" intervallic spelling. So the diminished 3rd of Gb would indeed be Bbbb. So why haven't we seen a Bbbb or any other triple flat? It's one of those things that exists theoretically but is never seen in actual music. Why would anyone ever want to use a diminished 3rd? What function would it serve to call it a diminished 3rd? That interval has no functional use to my knowledge.

    cheers,

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    I know that the diminished third of Gb would be enharmonically equivalent to Ab, but it is a third. So it must be written in terms of B.

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    Quote Originally Posted by Jed View Post
    Why would anyone ever want to use a diminished 3rd? What function would it serve to call it a diminished 3rd? That interval has no functional use to my knowledge.

    cheers,
    Now, I'm just a mere student, but what if the diminished third were in a chord that is to be resolved into a minor third? Or something similar.
    If I were the composer, I'd just write it as the second for clarity purposes. But theorists are much different from composers.

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    Quote Originally Posted by LRellim12 View Post
    Now, I'm just a mere student, but what if the diminished third were in a chord that is to be resolved into a minor third? Or something similar.
    If I were the composer, I'd just write it as the second for clarity purposes. But theorists are much different from composers.
    Rules about enharmonics are very tight in CPP (common practice era, basically "classical") music, and always make sense in context, often to do with alteration and resolution.
    Eg, an "augmented 6th" is what jazz or rock musicians would call a "minor 7th" - but in classical theory it derives from a specific alteration, and resolves in a specific way whicn means it has to be called an augmented 6th. In brief it resolves outwards (semitone each way) to an octave.

    In fact, the diminished 3rd is the inversion of an augmented 6th - and as such (I'm guessing ) would resolve inwards to a unison.

    Eg, if you have a chord Ab-C-F# (an "Italian 6th"), the augmented 6th is Ab-F#. So if the Ab were to be doubled above the F#, you'd have a diminished 3rd, F#-Ab. Either way, the resolution is to a G chord (V of C minor), with F# and both Abs moving to G.
    It would be theoretically wrong (ungrammatical, even nonsensical) to say F#-Ab was really a major 2nd (Gb-Ab or F#-G#). This is because the Ab is diatonic to the key (C minor), while the F# has been raised from F.

    The reason your Gb-Bbbb dim 3rd would not exist in practice is that it would come from the key of Dbb minor. How often do you see that???

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    For the sake of a beginner's theory assignment, though, would a triple flat be written? And if so, is there a specific symbol, or would it just be bbb?

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    Registered User JonR's Avatar
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    Quote Originally Posted by LRellim12 View Post
    For the sake of a beginner's theory assignment, though, would a triple flat be written? And if so, is there a specific symbol, or would it just be bbb?
    bbb, as far as I know. (There's no special symbol for a double flat, so I doubt there is one for a triple.)

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    There is a symbol for double flat but I have never seen a triple flat.

    double b, although you would rarely see this symbol. Is 'db' basically, but with no separation between the two characters. I learnt this one in high school from my music teacher, classically trained (pretty hot **** player with good credentials so I never doubted his word on this one). Then in later years the subject came up when i was studying jazz and my teacher thought I was crazy for even suggesting it.

    Sooo. Personally I would not think in terms of 'diminished third' It would be a 2nd.. In context to a chord It would be named x sus2.

    Ahh.. This site http://www.cgsmusic.net/Classical%20...%20Symbols.htm

    Gives double flat as just bb ... double Sharp is X too for those interested

    ciao.

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    use the tripple flat!

    i have never in my entire life heard of a symbol for a double flat (bb).

    that being said, if your theory teacher told you to put a diminished third on top of a Gb, you should slap a smile on your face and a Bbbb on your paper. although for the sake of simplification, try as hard as you can when writing your own music to avoid circumstances that would leave you trying to read something like that.

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    Quote Originally Posted by donald432 View Post
    i have never in my entire life heard of a symbol for a double flat (bb).
    No disagreement here.
    What we're saying is there IS a symbol for a double flat, but it's just that: a double flat "bb". (no separate special symbol.)
    Quote Originally Posted by donald432 View Post
    that being said, if your theory teacher told you to put a diminished third on top of a Gb, you should slap a smile on your face and a Bbbb on your paper. although for the sake of simplification, try as hard as you can when writing your own music to avoid circumstances that would leave you trying to read something like that.
    Agreed.
    The OP should also ask his/her teacher to give an example (from a real piece of music) where a triple flat is not only required theoreticaly but makes the music easier to read and understand than any alternative.
    (Such examples may well exist - but we need to know what they are!)
    Last edited by JonR; 05-03-2010 at 11:06 AM.

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