Chord Structure question

[JGilbear]

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?

[Jazzstdnt]

You may be thinking of a diminished 7th chord

[Jack E Blue]

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.

[FwLineberry]

F to A is a major 3rd. F to Ab is a minor 3rd.

[dconeill]

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.

[ragman1]

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?

Very good question!



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.

[matt.guitarteacher]

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.

Great post.

[ragman1]

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.

[FwLineberry]

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.

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.

[Jonah]

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.

However diminished chords are used in modern jazz... the terminology comes form their diatonic functional context, so you should realize what kind of mess in the head of a novice can create relating Bdim7 to B major and maming its bb7 a G#.
Do you?

[Jazzstdnt]

The intervals of a m7b5 chord are R b3 b5 b7 - based on the major scale of the root note of the chord.

.

I really don't mean to rag on you Ragman, but there is no need to bring the major scale or any scale into it.

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.

[Jack E Blue]

Anybody up for a good debate on how many angels can dance on the head of a pin?

[ragman1]

Flattening the b7 would give you Ab, so the correct spelling of Bdim7 is B D F Ab.

Not when related to B major which is a sharp key. Since G# and Ab are the same note the name can be changed according to context.

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.

Calling it m7b5 as opposed to a half-diminished is a personal preference, and that's what I said.

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.

[ragman1]

However diminished chords are used in modern jazz... the terminology comes form their diatonic functional context, so you should realize what kind of mess in the head of a novice can create relating Bdim7 to B major and maming its bb7 a G#.

The OP wanted to know how these chords are structured. The general way is to relate it to the major scale. I agree B major is tricky but at least with Bm7b5 we end up with nice clean notes without sharps and flats.

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.

[KirkP]

... 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...

I don’t who “it” is, but “it” is wrong. You are correct, it’s a major third.

[ragman1]

I really don't mean to rag on you Ragman, but there is no need to bring the major scale or any scale into it.

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.

I know, but I'm approaching it from the point of view of someone unfamiliar with this stuff. If there wasn't that confusion would the OP have asked his question?

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!

[Jazzstdnt]

Anybody up for a good debate on how many angels can dance on the head of a pin?

No, it's not that.

Both traditional and jazz theory courses tend to start with:

1. half steps and whole steps,
2. intervals,
3. scales (or scales then intervals)
4. 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...

[Jack E Blue]

No, it's not that.

Both traditional and jazz theory courses tend to start with:

1. half steps and whole steps,
2. intervals,
3. scales (or scales then intervals)
4. 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...

My snide remark wasn't directed at you. It was directed at the little back and forth about the "proper" name for an enharmonic. It drives me nuts when people get so pedantic about something so trivial.

Sorry for the misunderstanding.

[Jonah]

My snide remark wasn't directed at you. It was directed at the little back and forth about the "proper" name for an enharmonic. It drives me nuts when people get so pedantic about something so trivial.

Sorry for the misunderstanding.

It's not trivial.

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?

[FwLineberry]

My snide remark wasn't directed at you. It was directed at the little back and forth about the "proper" name for an enharmonic. It drives me nuts when people get so pedantic about something so trivial.

Sorry for the misunderstanding.

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?

[ragman1]

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.

[Jonah]

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.

What to explaine? THere is nothing to explain any more. He just made a mistake
"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

[Jazzstdnt]

My snide remark wasn't directed at you. It was directed at the little back and forth about the "proper" name for an enharmonic. It drives me nuts when people get so pedantic about something so trivial.

Sorry for the misunderstanding.

not a problem atall

[Jazzstdnt]

I know, but I'm approaching it from the point of view of someone unfamiliar with this stuff. If there wasn't that confusion would the OP have asked his question?

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!

OK I get it. Not bad.

[Jonah]

I know, but I'm approaching it from the point of view of someone unfamiliar with this stuff. If there wasn't that confusion would the OP have asked his question?

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!

On the contrary the formula is not related to the root major scale at all.

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.