I'll start:
From the lesson "FB Bb Jazz Blues Fingerpicking" discussing E Diminished 7th chord.
Tomo said:
The " Double Flatted 7th" note of a Diminished 7th chord is also the "Natural 6th".
When I heard this, I wanted to try to understand more about the concept.
The same note with 2 different names are called "Enharmonic equivalent" notes. C# = Db.
Edim7
E G Bb Db
R b3 b5 bb7
E MAJOR scale: E, F#, G#, A, B, C#, D, E
The natural 6th of the E MAJOR scale is C#.
C# can also be called Db. C# is the enharmonic of Db (and vice versa).
I compared the construction of Edim7 to Cdim7.
Cdim7
C Eb Gb Bbb
R b3 b5 bb7
C MAJOR scale: C, D, E, F, G, A, B.C.
The natural 6 of the C Major scale is the note A.
A can also be called Bbb, Bbb is the enharmonic equivalent of A. (and visa-versa)
Thanks for bearing with me as I am working through some of these concepts.
Kurt
OK Kurt now youāre just baiting me! My mind loves to chew on this stuff. The origin of the diminished seventh chord is the 7thĀ° degree of the harmonic minor scale. So: C-D-Eb-F-G-Ab-B harmonized from B = B-D-F-Ab > Bdim7.
What the Dim7 chord is called depends on the context and often involves a naming-change where sharps/flats can be used in the same spelling of the chord. In context, spelling can change if its function is a leading tone as compared to a dominant function. The adjustment is made based on context.
This explanation an 50 cents will get you a cup of coffee!
Thanks Ken! This is helping.
So, a diminished 7th chord is the 7th degree of the harmonic minor scale.
The Edim7 chord is just passing in the Bb jazz blues. Eb is the 4th note of the key of Bb,,and the note E is the sharp 4 of Bb, not in the key of Bb.
For Edim7, I related the notes of the chord to the E Major scale, not the songs' key which is Bb/G minor.
I was thinking the natural 6th degree of the key of E is C#. When I saw Tomo name it Db I spaced out and forgot it was the same note as C#!
The double flatted 7th note from the chord's Major scale is the natural 6th note located one whole step below the natural 7th degree of that major scale.
I owe you a coffee! I need something stronger :-)
Thanks so much!
Kurt
Hey Kurt, that is really cool how you worked that out in the forum -=logically=. A lot to write, yet you proved how it worked in comparison of two relative keys. I have also wondered about this topic with E and C- using sharps vs. Flats. You got me reviewing the relativity theory again, and yes it makes sense. Good to review. Now my question is when to apply a dim7 to what scale degree, any degree or mainly minor 2nd, and major 7th, or anywhere that fits in theory ?? In Bb jazz blues has is a diminished perfect 4rth or Ebdim7. Musical Brain teasers. .Thank you, - johno
Well, Seattle is the coffee capital of the US! So how about a cuppa and then a visit to see Joe? Double expensive entendres!
Tomo sees Edim7 here as #4 diminished which I like. Can it be seen in a dominant context?: Eb7(b9):
rootless where E is the b9 of Eb. If you spell it out youāll see it as related to Eb7.
Because diminished 7th spawns from harmonic minor it is difficult to see it related to the major scale. It will hurt.
Seventh degree of major scale is often referred to as half diminished 7th: in C: B-D-F-A (half diminished). So technically the proper naming of a diminished 7th chord would be to call it a ādiminished-diminished 7thā, but who has time for that! We are left with a mind tweaker due to the language thatās used.
This is helpful Ken and John! Come on up and over to Seattle and we'll have coffee, buy expensive guitars and get diminished-diminished or at least half- diminished :-)
Kurt