Sooo true!Legend has it that propper use leads to complete enlightenment.
II V I
Flat 5 substitution....
You take the V chord, and get it's b5, thus creating a "secondary dominant"....
II bII I
A chromatic progression where the bII is in most respects the same as
the V chord.
II V I
D G C
II minor 7th
D F A C
V 7th
G B D F
I Major 7th
C E G B
Now look at bII 7th
bII 7th
Db F Ab B
G7th has F and B... so does Db 7th.... close enuff to use in it's place....
You can look into this further but basically in every resolving chord
progression you'll find semi-tone movements between the chords... Their
root might be totally different, but the 3rd of one might be a semi-tone
from the 5th of another. This is why tunes like "Air on a G-String" sound
so balanced, it's always moving in 5ths and between each chord there are
several semi-tone movements... The instrumentation can make this more
obvious which is why some of the older classical tunes are good
examples... Specially when you have one instrument simply coming down
the chromatic scale with others picking up the notes of the chords which
move around more.
So without going into tooo much detail.... there is a relationship between
flat 5ths and semi-tones... and thus every chord progression....
Take it a step further...... You can use a process called "plurals" but I
never really "got it" so instead came at it this way....
Combine the chords above....
C Db D E F G Ab A B
Gives us a few more notes which relate to C Major yet aren't in the actual
scale, modes, harmonisation or whatever...
Now lets make the bII 7th from the last substitution our new V chord...
II V I
Ab Db Gb
II minor 7th
Ab B Eb Gb
V 7th
Db F Ab B
I Major 7th
Gb Bb Db F
Giving us....
Db Eb F Gb Ab Bb B
+
C Db D E F G Ab A B
=
C Db D Eb E F Gb G Ab A Bb B
Chormatic scale...... Now we have a way to include every single note in C
Major and feel good about it..... "Play what you feel!"
Lets have a look what happens if instead of using Db 7th as the new V
chord we instead use it as the new key (I chord Maj7th)...
II V I
Eb Ab Db
II minor 7th
Eb Gb Bb Db
V 7th
Ab C Eb Gb
I Major 7th
Db F Ab C (C was B in dom)
C Db Eb F Gb Ab Bb
+
C Db D E F G Ab A B (our original sub)
=
C Db D Eb E F Gb G Ab A Bb B
Damn what ya know.... Chromatic again....
So lets now try to skim it down a little, chormatic is great, but we need
something with gaps in it so we can use it....
Now if only I can remember how I derived Altered Scale from flat 5th subs....
-Ben