Question about Diminished and Half-diminished

**Rainer.** · 03-29-2009, 12:09 PM

Quote:

Originally Posted by Guitarbite1985

So if I play a G7 chord, the tritone substitution would be Db7...simply because to get a Diminished chord from the G7 you would have to diminish the 5th (with the addition of the minor 3rd); or more simplified Db is the tritone of G. That's what I get from it at least.

I think the more important relation of the chords is that they share a tritone dissonance between the notes B and F, while the root of Db is a half-step away from its new resolution of I, that is, C. Which is why it works as a leading chord into C.

Guitarbite1985 · 03-30-2009, 11:13 AM

Ah...very true Rainer. I see where you are coming from now. It also makes sense that B and F resolve back to C and E to complete the C chord as well.
I'm going to go back to the G7 chord for a minute. So from analyzing the G7 chord its dissonance comes from the B and F simply because they are a tritone pair?

**Rainer.** · 03-30-2009, 12:32 PM

Quote:

Originally Posted by Guitarbite1985

Ah...very true Rainer. I see where you are coming from now. It also makes sense that B and F resolve back to C and E to complete the C chord as well.
I'm going to go back to the G7 chord for a minute. So from analyzing the G7 chord its dissonance comes from the B and F simply because they are a tritone pair?

The tritone interval is dissonant, and those two notes beg resolution to C and E respectively.

Guitarbite1985 · 03-31-2009, 05:16 AM

Then, in theory, you could substitute both Bdim7 and Db7 for G7 and vice-versa because of their tritone interval relationship.

Nate · 03-31-2009, 06:07 AM

Quote:

Originally Posted by Guitarbite1985

Then, in theory, you could substitute both Bdim7 and Db7 for G7 and vice-versa because of their tritone interval relationship.

Sure.

**Rainer.** · 03-31-2009, 10:09 AM

Yeah, but the tritone substitution is an idiom much more common in jazz.

Guitarbite1985 · 03-31-2009, 03:58 PM

Which is good to know, because I'm starting to study jazz a bit. Speaking of jazz, I came across the Bebop scale. The explanation I got was that it is derived from the mixolydian scale with an added chromatic tone (I believe it is a half step down from tonic--from memory--), and is played descending.

G mixolydian (decending): G-F#-F-E-D-C-B-A

Am I understanding this correctly?