Diminished chords vs min7b5 chords

[AquaRover]

What is the difference between diminished chords and minor7b5 chords? and what are their basic functions within the major and minor diatonic sequences? I know the grips and the scale degrees for the most part, but i dont quite understand how to use these chords. Also how do they usually get notated?

Thanks!

[BigDaddyLoveHandles]

The minor seventh b5 chord is:
root, minor third, diminished fifth and minor seventh.

For example, Bm7b5 = B D F A

The most common use of a m7b5 is as the ii chord in a minor ii-V-i:

Bmin7b5 Ealt Aminor [EDIT: fixed it!]

I think by "Diminished" you mean a diminished seventh chord:
root, minor third, diminished fifth and diminished seventh.

For example, Bdim7 = B D F Ab

[ksjazzguitar]

A fully diminshed seventh (or dim7 or °7) is (1 b3 b5 bb7, also called the fully diminished 7th in classical) is often used as a leading tone chord, in other words resolving up a half-step to the target chord. It's often used as a sub for dominant chord, being built of the 3rd of the dominant chord (or any note but the root) giving a rootless X7b9. This is essentially the same as leading tone function.

It can also be a common-tone diminished. It is a Idim7 (or an inversion.) It is often seen resolving to I or as a connector from iii->ii.

The m7b5 (1 b3 b5 b7, called half-diminished or ø7 in classical) is commonly used as the ii in minor (or as a secondary ii paired with a secondary V.) It can also have leading tone function or sub as a rootless X9, similar to the dim7.

Peace,
Kevin

[lotuscent]

a min7b5 is also built off of scale degree 7 in the major scale, something i am certain both previous posters know, but did not mention. as they both mention, it is far more commonly used as a ii chord in minor.

the fully dim7 is not diatonic as it cannot be extracted from a natural scale or mode, and also very commonly used in bar 6 of a 12 bar blues, or to pass between two chords a whole step apart - Cmaj/C#dim/Dmin (my favorite Garth Brooks song!)

good luck, it's a harmonic jungle out there

[Jeremy Hillary Boob Ph.D]

Dim7 is built from minor 3rds. It can be built from the dim scale, and the harmonic minor. Most dim7 are rootless dom7b9 chords. The enharmonic spellings to indicate bass lines is very misleading. G#dim7 is vii of A HM. It leads to Am just like the V7 E7 (or rootless E7b9/G#)

The actual dim scale produces them as well. They are used to resolve to MAJ or Doms instead of minors in most cases.

***

The m7b5 aka half-dim id vii of the major scale (or ii of minor). As mentioned above, they are used in ii V7 i in minor (or modal interchange) progressions.

It also is the 6th mode of melodic minor. It is enharmonic of a min6th chord. ie Fm6/B and Bm7b are the same. They are also used as ii's in minor and as minor plagal cadence subs. ie Fm G7 C = Dm7b5 G7 C.

pwn

[NayNay]

Quite extensive, anyways, I'll give it a try... and probably will fail misarably...

so:

minor7b5: 1 b3 b5 b7

e.g.: B-7b5: b d f a

Harmonically:
Resolves to:
A half step up or down. Whatever you like.
(like this : Cmaj7 | Db-7b5 | D-7 | Eb-7b5 | E-7 | Fmaj7 | Gb-7b5 | G7 | Ab-7 b5 | A-7 | Bbmaj7 | B-7b5 | Cmaj7 | )

Every minor7b5 might also resolve into a Dom7 or maj7 on the same root (e.g. : B-7b5 | B7 | E-7 | or: B-7b5 | Bmaj7 | B-7 | E7 | A7 etc)

Furthermore, it might lead to a Dom7(alt) a fith down, which would then resolve into the VI-7 (e.g.: B-7b5 | E7#5 | A - )

Melodically:

scales to use: locrian #2, wholestep-halfstep(diminished), diminished pentatonic,

basically anything, as long as it covers the b3, b5 and b7 degrees. b9 might sound nasty if you over-use it.

Trivia:

can also be interpreted as a Imaj7b9 (IVmaj7 respectively) without the root.

dim7: 1 b3 b5 bb7

e.g.: Bdim7: b d f ab

harmonically:
almost identical to a minor7b5. Can be used in the same places as the minor7b5 in the progressions shown above.

melodically:
scales to use: locrian, halfstep-wholestep (BUT be caruful with that one), wholestep-halfstep (diminished), diminished pentatonic, chromatic

just dont hit a natural 3 on a heavy time. if you want to keep up the diminished feeling.


Trivia:

Can also be interpreted as a Dom7b9 without the root.

[Aristotle]

What is the difference between Diminished chords and minor7b5 chords?

A half-step.

Raise any of the four notes of he dimished chord a half step, and you have a m7b5.

[RunningBeagle]

-7b5 is also a rootless dominant 9. On the top 4 strings, in root position drop 2, this is a common James Brown chord. Most people don't bother inverting it for this function, though, which is a shame.

You can also find -7b5 hiding out in rootless 7b9b13 chords. For example G7b9b13 contains F, Ab, B (Cb), and Eb. And again, inverting it is totally dope.

So there you have it - a "natural" dominant substitution and an altered substitution. Root and 2nd inversion drop 2s are most common.

[lotuscent]

A half-step.

Raise any of the four notes of he dimished chord a half step, and you have a m7b5.

nice. that's actually pretty obvious and not obvious at the same time. never thought of that one.

[Aristotle]

nice. that's actually pretty obvious and not obvious at the same time. never thought of that one.

Usually it is said the other way around, lower any note a half-step and you get a 7th chord.

[lotuscent]

They are also used as ii's in minor and as minor plagal cadence subs. ie Fm G7 C = Dm7b5 G7 C.

pwn

trying to wrap my head around that one... i get it harmonically and aesthetically, of course, but it's the labelling - minor plagal cadence - that throws me off. i remember (perhaps wrongly) plagal as being IV-I (a-men was what prof used to say). could you explain?

[lotuscent]

Usually it is said the other way around, lower any note a half-step and you get a 7th chord.

i've been living in a cave...

[Flyin' Brian]

i've been living in a cave...

It's a big Pat Martino thing.

[lotuscent]

It's a big Pat Martino thing.

yeah yeah.
it's definitely something i know and do, but it's just funny how the easiest explanations sometimes are so obscured by circumtheoreticalogical avenues

[monk]

The minor seventh b5 chord is:
root, minor third, diminished fifth and minor seventh.

For example, Bm7b5 = B D F A

The most common use of a m7b5 is as the ii chord in a minor ii-V-i:

Bmin7b5 Galt Cmin

I think by "Diminished" you mean a diminished seventh chord:
root, minor third, diminished fifth and diminished seventh.

For example, Bdim7 = B D F Ab

I think you meant Dmin7b5 G7alt Cmin for your minor ii-V7-i example.

[JonnyPac]

I see boob's thing there. Fm to C is a "minor plagal cadence" Dm7b5 has the same notes. Dm7b5 to C is the cadence he mentioned. Tossing in the V7 is typical of doo-wop, etc. It's modal interchange.

[ksjazzguitar]

Trivia:

can also be interpreted as a Imaj7b9 (IVmaj7 respectively) without the root.

trying to wrap my head around that one... i get it harmonically and aesthetically, of course, but it's the labelling - minor plagal cadence - that throws me off. i remember (perhaps wrongly) plagal as being IV-I (a-men was what prof used to say). could you explain? [emphasis added]

Yeah, I'm not seeing that either.

Peace,
Kevin

[Ron Stern]

From the basic level, where I'm at, I figure, if they're only one note apart, is it possible to put them right up next to each other? So that whatever the difference is, it stands out?

Do like this:

Am7 (575555) Fm7b5 (x8989x) Fdim7 (x8979x) Am7 (575555)

. . . and you get a big chunk of You'd Be So Nice To Come Home To/Black Orpheus.

Why does the b5 come first? Because it's higher, and the basic idea is a descent. Why is it higher? Etc.

This is how I attempt to zero in on the difference between two things, in a way that I can hear and remember.

[NayNay]

Yeah, I'm not seeing that either.

Peace,
Kevin

The Imaj7b9. In C: c e g b db. The appropriate Scale would be Ionian (b2) or Lydian (b2).


The Term "Minor Plagal Cadence" is incorrect. A Plagal Cadence (IVm - I) is always in a major Key. If it were minor, it would not be plagal. then it would just be a normal IV - I in minor. Or a I - V in aeolian. Whatever. "minor plagal" simply does not exist.

However, in between the IV and the I you can put as many chords as you like. For example:

A-7 (IV-) | D7 | Ab7 | Gmaj7
Cmaj7 | Eb7 | Dmaj7 | B7 | Emaj7 (I)

Just to give an example. You can do whatever you like. Paint Pictures.

[ksjazzguitar]

The Imaj7b9. In C: c e g b db. The appropriate Scale would be Ionian (b2) or Lydian (b2).

I understood the term (though I doubt it's usefulness) I just didn't understand it's relation to the topic.

The Term "Minor Plagal Cadence" is incorrect. A Plagal Cadence (IVm - I) is always in a major Key. If it were minor, it would not be plagal. then it would just be a normal IV - I in minor.

Here we go again.

No, in traditional theory a plagal cadence is just IV-I, regardless of the qualities. Yes, it can be a iv-I using modal mixture, but usually in major it is IV-I and in minor it is iv-i. It can also be any kind of subdominant harmony - I remember Chopin using a ii7 in first inversion (which just resembles a IV with an added 6 - yes, they do sometimes talk about 6th chords in classical music.)

Now, looking around the net, some "pop" theorists call all their iv-I changes and backdoor turnarounds a "minor plagal cadence." Perhaps that's where the confusion arises. I think that is a confusing use of the term, unless it is truly functioning as a plagal cadence - an "amen" tag at the end of a song. (Jazz and pop people tend to label every V-I change as a cadence - really it's only a cadence if it closes a phrase.)

But in classical music, a plagal cadence just means substituting subdominant harmony for dominant harmony in the final cadence. "Plagal" just means "oblique" or "sideways" and comes from the same root as "plagarism." (We also have "plagal" modes in the early church where the range extends farther below the tonic, coming at it "obliquely.") There are some in the classical world that argue that the plagal cadence is not a real cadence but just an ornament.

Peace,
Kevin

[Aristotle]

From the basic level, where I'm at, I figure, if they're only one note apart, is it possible to put them right up next to each other? So that whatever the difference is, it stands out?
Do like this:
Am7 (575555) Fm7b5 (x8989x) Fdim7 (x8979x) Am7 (575555)
. . . and you get a big chunk of You'd Be So Nice To Come Home To/Black Orpheus.
Why does the b5 come first? Because it's higher, and the basic idea is a descent. Why is it higher? Etc.
This is how I attempt to zero in on the difference between two things, in a way that I can hear and remember.

Disagree that you are on a basic level with that analysis.

[Aristotle]

It also is the 6th mode of melodic minor. It is enharmonic of a min6th chord. ie Fm6/B and Bm7b are the same. They are also used as ii's in minor and as minor plagal cadence subs. ie Fm G7 C = Dm7b5 G7 C.

Ouch.

You know people can play the piano competently for 50 years, be very familiar with going from F to Fm from 100 different tunes, and know intuitively that the A gets flatted, but the other 6 notes of the scale are still the white keys. Or using the same note G#-Ab, if the chords go from C-E7, you sharp the G and all the other keys stay white. And never have any idea of what mode of what scale named for an ancient Eastern Mediterranean city-state or civilization it might be; and how that is the enharmonic equivalent of some altered synthetic non-Pythagorean scale invented by a music computer program in a basement lab Berklee (or Berkley, for that matter).

Sometimes this forum makes me glad I learned to play in the days of the dinosaurs, when we used to just change the one note of the major scale and keep going without circumnavigating permutation numerology; when basic piano lessons where required courses no matter what your instrument inlcuding voice. That's even before the melodic minor was the 5th mode of the Lydian b7. Now I guess the Lydian b7 is the 4th mode of the melodic minor.

Progress. Gotta love it.

[NayNay]

I understood the term (though I doubt it's usefulness) I just didn't understand it's relation to the topic.



Here we go again.

No, in traditional theory a plagal cadence is just IV-I, regardless of the qualities. Yes, it can be a iv-I using modal mixture, but usually in major it is IV-I and in minor it is iv-i. It can also be any kind of subdominant harmony - I remember Chopin using a ii7 in first inversion (which just resembles a IV with an added 6 - yes, they do sometimes talk about 6th chords in classical music.)

Now, looking around the net, some "pop" theorists call all their iv-I changes and backdoor turnarounds a "minor plagal cadence." Perhaps that's where the confusion arises. I think that is a confusing use of the term, unless it is truly functioning as a plagal cadence - an "amen" tag at the end of a song. (Jazz and pop people tend to label every V-I change as a cadence - really it's only a cadence if it closes a phrase.)

But in classical music, a plagal cadence just means substituting subdominant harmony for dominant harmony in the final cadence. "Plagal" just means "oblique" or "sideways" and comes from the same root as "plagarism." (We also have "plagal" modes in the early church where the range extends farther below the tonic, coming at it "obliquely.") There are some in the classical world that argue that the plagal cadence is not a real cadence but just an ornament.

Peace,
Kevin

Thanks for enlightening me.

[BigDaddyLoveHandles]

I think you meant Dmin7b5 G7alt Cmin for your minor ii-V7-i example.

Doh! You're right. I think I wanted to do that in A minor but I took the wrong turn on the interstate. I'm going to go back and edit it.

[ksjazzguitar]

...going from F to Fm from 100 different tunes, and know intuitively that the A gets flatted, but the other 6 notes of the scale are still the white keys.... Or using the same note G#-Ab, if the chords go from C-E7, you sharp the G and all the other keys stay white. ...

Not necessarily. I can think of many examples to the contrary. Usually I use F Dorian on that Fm and might use E Span Phrygian or E Altered or E Mixolydian or something else over that E7. For neither of those chords would I just change the one note. I think that that simplistic thinking is rather limiting.

And never have any idea of what mode of what scale named for an ancient Eastern Mediterranean city-state or civilization it might be;

You have this huge problem with geographical names. That was one of your big objections with the Neapolitan chord. They're just labels. If you don't like "Dorian," call it the "Waffle Freak Butternut Squash" scale. It matters how it's used, not your little anti-geography crusade.

Peace,
Kevin