[iltpff]

I am trying to fiogure out why the seventh chord in a key is a Diminished 7th and not just a Diminshed. I have seen it listed both ways and it seems to lean more heavily on haveng the Diminished 7th than the standard Diminshed.

Can anyone explain this as to which one is the standard, and if it is right or wrong to use one or the other at any given point?

Which one are we supposed to use as a standard?

[Fretsource]

Originally Posted by iltpff

I am trying to fiogure out why the seventh chord in a key is a Diminished 7th and not just a Diminshed. I have seen it listed both ways and it seems to lean more heavily on haveng the Diminished 7th than the standard Diminshed.

Can anyone explain this as to which one is the standard, and if it is right or wrong to use one or the other at any given point?

Which one are we supposed to use as a standard?

Are you talking about TRIADS or SEVENTH CHORDS?

If you're talking about TRIADS (3 note chords built from thirds), then the chord is DIMINISHED, not DIMINISHED SEVENTH.

If you're talking about SEVENTH CHORDS (4 note chords built from thirds) then the chord (in major keys) is HALF DIMINISHED SEVENTH

Only in minor keys does the true DIMINISHED SEVENTH chord appear as a chord built from scale notes.

[Fretsource]

I could have made that answer clearer
Take 2 ....

In C major (for example) the seven TRIADS (and chord notes) are:
C major (CEG)
D minor (DFA)
E minor (EGB)
F major (FAC)
G major (GBD)
A minor (ACE)
B diminished (BDF)

The seven SEVENTH CHORDS (and chord notes) are:
C major 7 (CEGB)
D minor 7 (DFAC)
E minor 7 (EGBD)
F major 7 (FACE)
G7 (GBDF)
A minor 7 (ACEG)
B half diminished 7 (BDFA) (aka Bmin7b5)

Neither of those lists contain a diminshed 7th chord

[iltpff]

Originally Posted by Fretsource

Are you talking about TRIADS or SEVENTH CHORDS?

If you're talking about TRIADS (3 note chords built from thirds), then the chord is DIMINISHED, not DIMINISHED SEVENTH.

If you're talking about SEVENTH CHORDS (4 note chords built from thirds) then the chord (in major keys) is HALF DIMINISHED SEVENTH

Only in minor keys does the true DIMINISHED SEVENTH chord appear as a chord built from scale notes.

Hi Fretsurce, I am talking about the 7th triad in a major key, which I see some make the 7th triad a diminshed 7th and some just dimished. Are you saying that only when teh key is a minor key that the 7th triad becomes a diminished 7th? I thought the 7th triad in a minor key was a Major chord?

[Fretsource]

Originally Posted by iltpff

Hi Fretsurce, I am talking about the 7th triad in a major key, which I see some make the 7th triad a diminshed 7th and some just dimished. Are you saying that only when teh key is a minor key that the 7th triad becomes a diminished 7th? I thought the 7th triad in a minor key was a Major chord?

Now that I know you're talking about TRIADS I can say definitely that the vii chord is DIMINISHED only, not any kind of 7th chord. Triads can only be major, minor, diminished and augmented. It's impossible for a triad to be a diminished seventh or any kind of seventh - they've only got 3 notes.

As for the minor key. Yes chord VII is Major if using the natural minor scale. But if you use the harmonic minor scale, chord vii is diminished. And if you take 4 notes instead of 3 you get diminished 7th
For example, in A harmonic minor
ABCDEFG# A
G# diminished 7 = G#BDF

[iltpff]

Originally Posted by Fretsource

Now that I know you're talking about TRIADS I can say definitely that the vii chord is DIMINISHED only, not any kind of 7th chord. Triads can only be major, minor, diminished and augmented. It's impossible for a triad to be a diminished seventh or any kind of seventh - they've only got 3 notes.

As for the minor key. Yes chord VII is Major if using the natural minor scale. But if you use the harmonic minor scale, chord vii is diminished. And if you take 4 notes instead of 3 you get diminished 7th
For example, in A harmonic minor
ABCDEFG# A
G# diminished 7 = G#BDF

Thanks for the info, I guess the confusion is that I have been to numerus sites and they did in fact show a diminished 7th triad as the seventh one in the key in a major scale. I wonder why they are doing this? Also, there is a book called "How to play guitar in every key" that shows either a diminished or diminished 7th triad as the seventh chord in a key.. go figure. No wonder there is so much confusion abroad.

[Fretsource]

I've often seen the half diminished 7th included for practical reasons. They show 6 triads but the one built on note seven of the scale, they make it a half dim7 instead of the simple diminished triad because the diminished triad is about the most useless chord out there. It's very weak and there aren't many decent shapes for it.

But if they include the fully diminished 7th chord, then that's just plain wrong. The dim 7 always contains a foreign note.

But another source of confusion is the symbol °
It actually just means diminished but many song book publishers use it to mean diminished 7, when they should really write °7.