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Hi I am a newbie jazz guitar player and I have a question about chord structure specifically with the b half diminished seventh chord. Now the chord structure is 1b3b5b7 and my question is there is minor 3rd on the second and third notes but on the 4th note of the chord structure it’s says there is suppose to be a minor 3rd but to my knowledge it is a major 3rd because there is 4 half steps or semitones from the previous note.
B TO D MINOR 3RD
D TO F MINOR 3RD
F TO A MINOR 3RD BUT WHY ISNT IT MAJOR 3RD THERE ARE 4 HALF STEPS?
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11-10-2018 03:08 PM
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You may be thinking of a diminished 7th chord
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JGilbear,
I know just enough music theory to be dangerous. However, I'll give it a shot.
The Half-diminished chord is also known as a minor 7 flat 5 (Bm7b5). Which to me is more descriptive. In a fully diminished 7th chord (Bdim7) the 7th degree is flatted twice - 1 b3 b5 bb7. A double flat 7th is enharmonic with a 6th.
That's why it's called "half-diminished." The 7th degree isn't fully diminished.
Half dim = stacked minor 3rd, minor 3rd, major 3rd
Full dim = stacked minor 3rd, minor 3rd minor 3rd.
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F to A is a major 3rd. F to Ab is a minor 3rd.
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The m7b5 or half-diminished chord is diatonic to the major scale 7th degree. For the key of C major, the pitches are B D F A, with intervals m3 m3 M3, or relative to the chord tonic the pitches are 1 b3 b5 b7.
The fully diminished 7th chord is diatonic to the harmonic minor scale 7th degree. For the key of A harmonic minor, the pitches are G# B D F, intervals m3 m3 m3, or relative to the chord tonic the pitches are 1 b3 b5 bb7.
You can generate these chords by "harmonizing the scale in thirds", which means start with the scale; then stack on top of the scale tone the scale pitch a third above it (e.g., E above C, F above D, and so on); then stack on top of this diad the next third (e.g., G above E, A above F, etc.). To this triad add another pitch a third above the last (e.g., B above G, C above A, and so on). This four-note chord is a 7th chord. You can keep going with this recipe to get diatonic 9th, 11th, and 13th chords.
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Originally Posted by JGilbear
If you count in m3s from the root B you get, as you say, an Ab at the end, not an A.
So that's not how it's done.
The intervals of a m7b5 chord are R b3 b5 b7 - based on the major scale of the root note of the chord.
B major is B C# D# E F# G# A#
So, following the formula R b3 b5 b7 above, the notes are B D F A.
Voila.
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Originally Posted by dconeill
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Incidentally, the formula for a diminished 7 chord is 1 b3 b5 bb7*. Applying that to a Bdim7 from B major you get
B D F G#
which is correct.
(The name half-diminished is popular but I don't think it really describes the chord accurately. Half of what? So personally I prefer m7b5. Easier to understand.)
* 'Diminish' means flatten, so you've got to flatten the b7, hence bb7.
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Originally Posted by ragman1
Flattening the b7 would give you Ab, so the correct spelling of Bdim7 is B D F Ab.
As to half diminished, there are two diminished intervals in a diminished 7th chord - the 5th and the 7th. if only one of those intervals is diminished (the 5th), you have half diminished.
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Originally Posted by ragman1
Do you?
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Originally Posted by ragman1
Chords are certainly generated by the harmonization of scales, but we don't need scales to form chords. Chord qualities need only be defined in terms of the interval qualities relative to the root. In this case:
minor 3rd
diminished 5th
minor 7th
BTW - m7b5 also occurs when we harmonize the Melodic and Harmonic Minor scales.
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Anybody up for a good debate on how many angels can dance on the head of a pin?
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Originally Posted by FwLineberry
In G major, for example, the progression GM7/G#o - Am7 is commonplace. It's not called Abo.
As to half diminished, there are two diminished intervals in a diminished 7th chord - the 5th and the 7th. if only one of those intervals is diminished (the 5th), you have half diminished.
Someone who wasn't familiar with all this would find it much easier to imagine a m7 chord with its fifth note flattened than trying to imagine half a diminished chord, that's all.
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Originally Posted by Jonah
Diminished chords can also be related to the major scale of their root. The formula for a dim7 is 1 b3 b5 bb7. Without a reference point that is a meaningless statement. Flat 3 of what? Double-flat 7 of what?
Or he can just carry on wondering why, if Western harmony is tertiary, the intervals of a m7b5 chord are two minor thirds and a major third.
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Originally Posted by JGilbear
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Originally Posted by Jazzstdnt
Here it is:
'I have a question about chord structure specifically with the B half diminished seventh chord. Now the chord structure is 1b3b5b7 and my question is there is minor 3rd on the second and third notes but on the 4th note of the chord structure it’s says there is suppose to be a minor 3rd but to my knowledge it is a major 3rd because there is 4 half steps or semitones from the previous note.'
He couldn't understand why, if the formula of a m7b5 is 1b3b5b7, and Bm7b5 is the 7th chord of C major, why is one of the intervals a major third and not a minor one?
That's what he wanted to know. He doesn't understand what 1b3b5b7 refers to. Why b3? Or b5? Or b7? What of? I've told him, the B major scale.
In short, if you want to use the formula use the root major scale. If you don't want to use the root major scale, ignore the formula!
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Originally Posted by Jack E Blue
Both traditional and jazz theory courses tend to start with:
- half steps and whole steps,
- intervals,
- scales (or scales then intervals)
- then chords
If every time you want to discuss a different chord quality you have to drag a scale reference around with you it only adds to the confusion.
If one knows their intervals they can understand the half diminished or m7b5 chord as result of the intervals involved - nothing more. And the same goes for every chord. Bottom line - chord names are descriptive of the intervals in them, not their parent scales.
If every chord quality was generated by one and only one scale source - and degree* - then maybe it would be different, but it ain't.
* m7b5 is harmonized from both degrees 6 and 7 of the Mel. Minor scale, for example, not to mention degree 7 from Major, or degree 2 from Harm. Minor...
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Originally Posted by Jazzstdnt
Sorry for the misunderstanding.
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Originally Posted by Jack E Blue
The way we name things is the way we understand them.
Correct names for enharmonic intervals is very important for understanding how functional tonality works, espcially at the beginning of learning process.
The fact that today we begin to see enharmonic as rudimental is connected with integration of equal temeperament that as consequence changed the musical language...
Strictly speaking lots of modern music (including modern jazz) even when it looks functional ofte is about 12 tones (not in Schoebergian sense)... and to be absolutely correct totally new termonology and theory is needed to describe it (CST is probably one of the attempts to create it... maybe not the most succesful).
So far we use terminology borrowed from classical music and this terminology describes functional tonality, function is the key word there - not scale, mode, voice-leading - though is all there - bit function is the charaterestic feature of it...
Besides... even now and even in modern music G# and Ab and Bbb can be three different pitches in different contexts! It depend on the player's ears skills and the possibilities that the instrument gives to him.
So when you begin teaching from Bdim7 is B-D-F-G# (which is wrong because of key (and fucntion within a key) it is related to first of all) you actually cut a student from possibility to hear differences I described above...
Is it trivial?Last edited by Jonah; 11-13-2018 at 05:06 AM.
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Originally Posted by Jack E Blue
Sorry, I thought this was a discussion about theory.
If somebody insisted on calling a Les Paul a Stratocaster, would it be trivial to point out the error?
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Jonah -
Then you will have to explain to JGilbear (who's probably gone off and asked somebody sensible by now) what the formula means. He introduced it and there's nothing wrong with it.
The formula for a m7b5 chord is 1b3b5b7. Would you dispute that? No? Good.
So explain what that means. Go ahead.
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Originally Posted by ragman1
"the chord structure is 1b3b5b7 and my question is there is minor 3rd on the second and third notes but on the 4th note of the chord structure it’s says there is suppose to be a minor 3rd'
No, it's not supposed to be a minor 3rd. In half-diminished it's supposed to be a major 3rd.
And that was explained to him immidiately by a few members
(FwLineberry even made it in just one sentence actually.)
If he asks more question I will explaine.
Regards
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Originally Posted by Jack E Blue
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Originally Posted by ragman1
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Originally Posted by ragman1Originally Posted by ragman1
Formula is chord roots + intervals, in the formula they are abstract from any scale. That's the whole sense of these formulas actulaly.
b7 is always minor7th and 7 is always major7th, no realtions to any scale (the whole chord has functional or scale relations, but formula does not represent it).
Essentially the formula is not realted to scale at all, it is purely intervalic.
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