diminshed 7th chord

patb

Blues Junior
Can anyone direct me to a segment explaining and demonstrating a diminshed chord and dimished 7th chord?
Thanks, Pat
 

ChrisGSP

Blues Journeyman
There's a lesson somewhere in the BGU Blog on the Peter Green song "Need Your Love So Bad" which has a diminished chord in it - maybe Griff explains the chord in that lesson, I don't remember.
Apropos your question - Be aware - my understanding is that the Diminished chord and the Diminished 7th chord are exactly the same thing - a Tonic (Root), Flat 3rd, Flat 5th, double-flat 7th. In C that's C, Eb, Gb, Bbb (which is the same as A).
Do Not mistake that for the "half-diminished" or Minor 7th Flat 5 chord, which is a Tonic (Root), Flat 3rd, Flat 5th, Flat 7th. In C, that's C, Eb, Gb, Bb.
The half-diminished has a Flat 7th, while the (full) diminished has a double-flat 7th (enharmonic of the 6th).
 

david moon

Attempting the Blues
There's a lesson somewhere in the BGU Blog on the Peter Green song "Need Your Love So Bad" which has a diminished chord in it - maybe Griff explains the chord in that lesson, I don't remember.
Apropos your question - Be aware - my understanding is that the Diminished chord and the Diminished 7th chord are exactly the same thing - a Tonic (Root), Flat 3rd, Flat 5th, double-flat 7th. In C that's C, Eb, Gb, Bbb (which is the same as A).
Do Not mistake that for the "half-diminished" or Minor 7th Flat 5 chord, which is a Tonic (Root), Flat 3rd, Flat 5th, Flat 7th. In C, that's C, Eb, Gb, Bb.
The half-diminished has a Flat 7th, while the (full) diminished has a double-flat 7th (enharmonic of the 6th).
A lot of times that 4th note in the chord doesn't even count. It's just the half step of the root passing to the next chord and the resulting b5 and b3,
 

Paleo

Student Of The Blues
To avoid confusion many musicians reserve the term “diminished chord” strictly for the “fully-diminished” 7 chord (1 b3 b5 bb7). Fully diminished because both the 5 and 7 are diminished, resulting is 3 stacked minor 3rds. There are only 3 of these chords, since moving up or down 3 frets results in an inversion of the same chord. This is not a chord naturally occurring on the 7 of a Major scale.

You can use m7b5 for the “half-diminished” 7 ( 1 b3 b5 b7) where only the 5 is diminished and the 7 is minor; a Major 3rd on top of 2 minor 3rds.

And mb5 for the “diminished” triad ( 1 b3 b5) where the 5 is diminished and you have 2 minor thirds stacked atop each other.


In Griff's lessons:

For theory, the only full lesson I know of that Griff did was the November 15, 2019, AAP Live Session on the Diminished Arpeggio.

In "Guitar Theory Made Useful", he discusses the construction of the diminished and m7b5 chords in Lesson 7 on Tall Chords (Dominant/Altered family, from 8:35 to10:30).

He discusses the diminished triad in Lesson 6 on "Basic Chords" and Lesson 9 on "The Standard Harmony Rule".

For fingerings:

In “Acoustic Blues Unleashed” he introduces a diminished chord diagram with the root on the 4th string on Page 89 in Lesson 22, “Mean Old Woman Blues”.

He also uses this fingering in “Nobody Knows You” and in “Deep River Blues”.

In “Amazing Grace” he uses the root on the 6th string fingering.

That's all I got.
 
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Paleo

Student Of The Blues
And finally, most likely only for my own amusement.

Using the “root on the 4th string” form for C diminished (C Eb Gb A) at the 10th fret

Eb----------Gb---------A-----------C----------Eb (1st string)

-A------------C----------Eb---------Gb---------A

Gb-----------A----------C-----------Eb--------Gb

-C-----------Eb--------Gb-----------A----------C (4th string)


Moving up 3 frets (minor 3rd) at a time results in the same 4 notes and repeats starting with C an octave higher at the 22nd fret.

Vertically across the neck:

C diminished = Eb diminished = Gb diminished = A diminished

Each chord is spelled "in order" horizontally going up each string.

( "Juggling" some enharmonic spellings.:sneaky:)
 
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