For sure, the Minor7b5 chord is less common, but you need to have it under your fingers!
View the full lesson at Minor 7♭5 Chords | JustinGuitar
When making the C7, by flattening the 7th to Bb, where is the 5th, G in the cord?
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Hi James,
In the minor 7b5 chords the 5th is also flattened, so in C min7b5 you have a Gb instead of a G note.
In dominant 7th chords the 5th is optional.
That’s what I was wondering, in the Dominant C7…the G turns into a flattened Bb 7th…so it’s optional, Thanks
So honestly up to this lesson I have gotten everything quite easily but HOW and WHY we make these different chords is just killing me! Has anyone else run into this in the past and what did they do to get through it. Justin also always makes so much sense but now I don’t understand him, he is glazing over chords and it’s confusing!!!
I think a big part of my struggle is that it’s only been a few months since I understood where the notes on the keyboard are but knowing where to find them and memorizing them are two very different things!
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James. Can I suggest the way you asked this question is coming it at from a problematic perspective.
There is no B note, 7th scale degree, within a C major chord.
So to think of flattening it is not helpful as it isn’t there in the first place.
Making a dominant 7 chord is all about adding something to a triad.
C = 1, 3, 5 = C, E, G
C7 adds something to that triad.
C7 = 1, 3, 5, b7 = C, E, G, Bb
When played s a chord in open position on the guitar, we actually omit the 5th, the note G, entirely.
This is perfectly fine and quite common in extended chords. The 5th of any chord when extended can be played or not played and it does not affect the quality of the chord type whatever.
No to the first part (see my previous comment) and yes to the second part.
Cheers 
| Richard | JustinGuitar Approved Teacher, Official Guide & Moderator
@Lasher I’m not sure how to help as you don’t ask a specific question. Are you still struggling?
Cheers
| Richard | JustinGuitar Approved Teacher, Official Guide & Moderator
I’m not sure either. I seem to have put down the theory course at this point because I am finding it a bit difficult at this point. I have learner my Major 7th chords and am currently learning my Dom 7th cords the whole “quadad” concepts I am finding a bit overwhelming so for the past few months i have been focusing on other things.
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HOW
As with all chords learned up to this point, the how is relatively straightforward. They are made by stacking thirds. The exact same concept you will have seen when learning triads simply gets extended to the next leap in the sequence.
Key points to know as you read this.
Major third = four semitones
Minor third = three semitones
Use the Note Circle as a guide also.
Looking at the C major scale and the seven quadad chords derived from each of its scale degrees.
All chords must by definition be made only from notes within the C major scale.
For each and every chord, the numeric name of the 3rds and 7ths (whether flat or not) is found with reference to the major scale of the chords root note.
C major 7
C = 1 (root)
E = 3
G = 5
B = 7
Each note is found at an interval of one third from the previous note. The interval from root to 3rd is a major third so the chord is a major type.
D minor 7
D = 1 (root)
F = b3
A = 5
C = b7
Each note is found at an interval of one third from the previous note. The interval from root to 3rd is a minor third so the chord is a minor type.
Why is the 3rd a b3 and why is the 7 a b7?
Look at the D major scale: D, E, F#, G, A, B, C#
Within that scale we have C# and F#. Within the chord we have C and F. Therefore the 3rd and 7th scale degrees from the D major scale must be flattened to match the 3rd and 7th within the chord.
E minor 7 quadad
E = 1 (root)
G = b3
B = 5
D = b7
Each note is found at an interval of one third from the previous note. The interval from root to 3rd is a minor third so the chord is a minor type.
Why is the 3rd a b3 and why is the 7 a b7?
Look at the E major scale: E, F#, G#, A, B, C#, D#
Within that scale we have G# and D#. Within the chord we have G and D. Therefore the 3rd and 7th scale degrees from the E major scale must be flattened to match the 3rd and 7th within the chord.
F major 7 quadad
F = 1 (root)
A = 3
C = 5
E = 7
Each note is found at an interval of one third from the previous note. The interval from root to 3rd is a major third so the chord is a major type.
Here we have a 3rd and a 7th (no alteration).
Look at the F major scale: F, G, A, Bb, C, D, E
The notes within the chord are all found in the scale, none of them need to be altered to match.
G dominant 7 quadad
G = 1 (root)
B = 3
D = 5
F = b7
Each note is found at an interval of one third from the previous note. The interval from root to 3rd is a major third so the chord is a major type.
Here we have a 3rd and a flat 7th. Why is the 7th a b7?
Look at the G major scale: G, A, B, C, D, E, F#
Within that scale we have B and F#. Within the chord we have B and F. Therefore the 3rd can remain as is, unaltered, but the 7th scale degree from the G major scale must be flattened to match the 7th within the chord.
A minor 7 quadad
A = 1 (root)
C = b3
E = 5
G = b7
Each note is found at an interval of one third from the previous note. The interval from root to 3rd is a minor third so the chord is a minor type.
Why is the 3rd a b3 and why is the 7 a b7?
Look at the A major scale: A, B, C#, D, E, F#, G#
Within that scale we have C# and G#. Within the chord we have C and G. Therefore the 3rd and 7th scale degrees from the A major scale must be flattened to match the 3rd and 7th within the chord.
B minor 7 flat 5 quadad
B = 1 (root)
D = b3
F = b5
A = b7
Each note is found at an interval of one third from the previous note. The interval from root to 3rd is a minor third so the chord could be seen as a minor type … BUT … the interval from 3rd to 5th is also a minor third meaning this is a diminished type of chord.
Why is the 3rd a b3 and why is the 5 a flat 5 and why is the 7 a b7?
Look at the B major scale: B, C#, D#, E, F#, G#, A#
Within that scale we have D#, F# and A#. Within the chord we have D, F and A. Therefore the 3rd and 5th and 7th scale degrees from the B major scale must all be flattened to match the 3rd, 5th and 7th within the chord.
Think of this as a minor chord but with a b5 - hence the name.
It can also be called a half diminished.
I hope that helps.
Cheers
| Richard | JustinGuitar Approved Teacher, Official Guide & Moderator
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Coming from a keyboard background why is this called a Minor 7thb5 in reality this is a diminish 7th.
First the 3rd is flatten for the minor, then the 5th is flatten which makes this a diminish chord. then add the 7th. So starting with a C Chord c e g it becomes c eb gb (C diminish) then add the 7th a Bb. I like the sound of it with the 7th added without it you’ve got the diminish sound. Is this just another way of naming this type of chord. I have seen this same chord named as a Minor 7thb5 and a diminished 7th. Just Curious???
Thanks John Boy
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Hey John,
In a m7b5, the 7th is minor. So you have a diminished triad with m7. Also called half diminished because its only the triad thats diminished.
So in your example, you have C-Eb-Gb-Bb. All stacked minor 3rds.
In a dim7, both the triad and the 7th are diminished.
So from your example you would have C-Eb-Gb-Bbb.
So its the quaility of the 7th thats the difference.
Cheers, Shane.
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Correct. Diminished can have several meanings, so it can be helpful to describe diminished chords more explicitly.
A diminished C chord can be:
- a diminished triad = C Eb Gb
- a half-diminished 7th = C Eb Gb Bb (AKA the minor 7 flat 5)
- a full diminished 7th = C Eb Gb Bbb
And then there are a zillion ways to notate / symbolize the chord. Shamelessly taken from Wikipedia:
Half-diminished seventh chords are often symbolized as a circle with a diagonal line through it, as in Cø7 or simply Cø. It also can be represented as (e.g.) Cm7♭5, C-7♭5, Cm7(♭5), etc.
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Hi Shane & Jeff
Ahh, I see now🙃, I did not know the 7th is also diminished in a dim7 makes sense now.
Thanks for that great info. I’ll be keeping this email in my Theory folder
Thanks👍!!
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Another addition to the great explanations offered by @sclay and @Jeff …
Think of the naming (minor 7 flat 5) as indicating that you have what is, in essence, a minor 7th chord but with the crucial difference being that its 5th is flattened.
In using this particular choice of name, the implication is that minor 7 refers to the substantial part and flat 5 refers to the alteration compared to a minor 7. Whilst that might not be the most technically accurate view (because a m7b5 undoubtedly derives from, is an extension of, a diminished triad), it is the one commonly used. In guitar land at least.
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Am7 = 1, b3, 5, b7 = A, C, E, G
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Am7b5 = 1, b3, b5, b7 = A, C, E, Gb (A half diminished)
Also
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Am7b5 = 1, b3, b5, b7 = A, C, E, Gb (A half diminished)
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Adim7 = 1, b3, b5, bb7 = A, C, E, Gbb (A full diminished)