So in a KEY you have 3 functions
Tonic ( relaxed
Subdominant ( tense
Dominant ( the most tension that moves toward tonic )

So C lydian occurs in G major Key as a Subdominant ( tense )
But C lydian occurs in the C major KEY
As a tonic ( home, relax )
So the answer is that is different for each key.

The way to understand this.
Is to look at how all 12 notes work per key.

In C major
Our dominant is G7


GBDF G# A A#. C#. D#
1357. b9 9 #9. #11 b13

So no F# in G7 but F# is #11 for the tonic Cmajor

CEGBDF#A
13579#11.13

G7 resolves to C lydian

Where in G major , C lydian is a Subdominant .

Cmaj7/ D7/ Gmajor)

So you have this cool thing that any chords in G major Key can be played in C major key ( just function is different )

Think of it as the 4 chord of the key a fifth higher than yours is the tonic of yours ( it's based in the 12 notes of your current key though )


Take A key say C major.

So let's take C ,E, G

How does all other of the 12 notes resolve to these ?

C is C
C# resolves down to C
D resolves down C or up to E or stays still ( as 9th
D# resolves up to E
E is E
F resolves down to E
F# is #11 in Cmaj
G is G
G# resolves down G or up A ( A is 6th in Cmaj
A is 6th in Cmaj
A# resolves down to A or up to B ( b as 7th in CM
B resolves up to C ( or stays still as maj7th CEGB
C is C

So that's C major how all 12 notes relate
So C lydian is this.
CEGBDF#A
13579#11.13

Yes it is in G major ,but that's not what we looking for in terms of C major .
We looking at how any of 12 notes resolve to C,E,G
( That's what it means to be KEY of C major that C major is the tonic )
So a KEY
Means a center focus.
A point of home base or relaxation.

Key of C major it's that C,E,G, is home base .
And that you still have all 12 notes in this KEY
But they are moving toward the point of relaxation.
There's tonic as the center point .C,E,G notes

There's dominant as the tension that has to resolve to C,E,G notes.

And Subdominant is just some tension moving toward either dominant or tonic.

The Subdominant combines notes from the tonic and the dominant .

Let's take a look.

The Subdominant in key of C major is 2 chords.

2.Dmin7 DFAC
4.Fmaj7 FACE


So looking at 2 chord DFAC
We have the D from G7 dominant
We have the F from G7 dominant
Then we have the A from Cmajor tonic
We have the C from C major tonic.

Let's instead look at 4.FACE

We have F from G7 dominant
We have A from G7 dominant ( A is 9th of G7
We have C from C major tonic
We have E from C major tonic

So any chord progression in the key of C follows this function movement


Tonic/ Dominant/ Tonic/

Tonic / Subdominant/ Tonic

Subdominant/ dominant/ tonic/

These are like blueprints for chord Progressions .


We have non diatonic substitutions as well.

IVminor category in C major

Fmin7 resolves to Cmaj7

Bb7 resolves to Cmaj7


Also #IV diminished .

F#dim7 resolves to Cmaj7

This just means that no matter how complex music
You write in the key of C major .

Is always simple in terms that how the 12 notes resolve to C,E,G,

Then simply breaking down to 3 functions .
Tonic
Subdominant
Dominant

When you get to the more advanced substitutions.
It's still that simple.


Take #IV ( non diatonic Subdominant substiutions


F#dim7/ Cmaj7/

Subdominant to tonic

F#ACD# resolved to CEGB

In this case this F#dim is a Subdominant resolving to tonic.

Subdominant/ Tonic/

( It just means there's more variety then only having
Dominant resolving to tonic.)

So even bumping up against to most complex music you can make in a key it always works the same as the simple diatonic progressions .

Fmaj7/ Cmaj/
IV to I

F#Dim7 / C6
IV to I

So no matter how complex you ever write music
( Even going to the maximum complexity it can offer )

It's a matter of seeing how all 12 notes resolve to your keys tonic.
( As demonstrated above )

Disclaimer
{
This entire explanation is regarding
" Functional harmony in 12 tone ET "
If your dealing with another context things work different than this explanation offers .}

 

Last edited: May 1, 2020