OT: small theory question

forgive me if i'm saying a lot of stuff you know already.

the IV of IV is has a blues feel for a number of reasons. most of them have to do with the fact that you're setting up a false cadence that seems to make the IV chord a resolution (since gospel is as likely to resolve from IV-I as it is to resolve from V-I). a lot of blues and jazz uses the retrograde circle of 5ths movement (C-F-Bb-Eb-Ab-etc.) which as you can see, is a circle of 4ths.

a) when you're using a fourth substitution with triads, the IV of IV in F is a Bb triad, which is pulling in the dominant seventh note from C (and blues uses dominant 7ths a lot, as you know)

b) if you're using dominant 7th chords, the IV of IV has the flat 3rd degree in it. in other words, if you're in C, and playing a blues, when you substitute in a Bb7 over the F7, you're picking up an Ab, which would ordinarily be way out of key, but sounds consonant because blues scales tend to always sound in key, and it also sorta feels like the blues scale in F.

c) The combination of Bb-D-F-Ab (the 4, 13, 1 and b3 of the IV chord) also leans towards the feeling of a natural minor scale for the tonic chord (since these notes are the b7, 9, 4, and b6 of the tonic), and blues is all about major and minor laid on top of each other.

d) that bVII triad (which is really what the IV of IV is) also has a nice sus4 feeling in relation to the tonic and the IV chord. it "feels" more modal because you're emphasizing notes that would be avoided in conventional diatonic harmony. a lot of jazz players use the blues scale based on the 5th degree of the scale (so it's like using a G minor blues over a C blues progression) because it has a more modern sound. that Bb triad really implies a G minor blues scale. when you put together the weak IV cadence and some substitutions, you get the essence of gospel as a quasi-modal style, which i guess it is in a way.

I know there are more reasons. And I'm also pretty positive that most gospel players don't think about it this way, but that's okay.

thanks johann

that was a very nice detailed answer
i had an intuitive feel for some of that
but was too lazy to work it out
and you laid it out really well
with a lot of information new to me
thanks

there's a few other sections i found at the site that i'll be exploring soon as well
one i can't find now had to do with something like backfilling using the circle of 5ths
you want to get ffrom C to G, but you back fill C A D G to get there

and in a few days teh whole Coltrane changes
http://www.angelfire.com/fl4/moneychords/coltrain.html
that looks really interesting
but i'm not ready for that

Good job gourd,


Nice stuff here.
I have always just accepted that one as... well it's sounds good that's just the way it goes.
I think in ancient music they also made use plagal cadences.

I especially like the bVII(IV / IV) = 7sus/I theory, which relates the IV/VI to the I chord.
Check this, take this classic plagal cadence, "Yesterday" :

Dmin7 G7 / Bb F

This Bb - F is typically plagal. Now take the Bb chord and replace it by Bb\C.

Dmin7 G7 / Bb\C F

That gives you a form of V - I cadence and the sound is very similar.

The IV also has a grace note quality down to the I, especially in the 2nd inversion.

C F A resolves on
C E G

This I think also makes it a very strong chord movement.