The Concept Of Three IV Chords

​     The primary intention of Modal Jam Theory is to provide a structure of thought that affords an approach to experimenting with the sound(s) of modal triads (G C F Bb Eb Ab Db) that are 'suspended' over various 'Bass Roots.'
​     Modal Jam Theory suggests the employment of three unique 'harmonic shapes' for beginning this exploration.
​
     

       

    
              The Harmonic IV Chord

     
​     In Diatonic Harmony - the harmony of the IV Chord is [virtually] inevitable... when the tone 'Fa' makes an appearance (on any harmonic pulse) in the melody. At the moment the IV Chord ('F') occurs -- 'Do' ('C') becomes the perfect fifth of that IV Chord -- and sounds like 'So.' 
​     The following harmony suggests an 'F' triad -- with the Bass Player enjoying a 'C' note. In this scenario: 'Do' ('C') sounds like 'So' -- and 'C' Mixolydian is the melodic terrain. We could refer to this 'harmonic shape' as 'The Harmonic IV Chord' -- I call it the 'Harmonic Shape of Mixolydian.' 

 


​             
   
                        The Melodic IV Chord

​     When 'Do' pivots to become 'So' -- a new 'Fa' is created that is one whole-step down from that 'Do.' This suggests that any time we hear the progression of 'Cma' -- 'Bbma' -- it sounds like 'V' - 'IV' (double pivot). But what happens when we 'keep' the triad that causes 'Do' to sound like 'So' ('F') and (simply) move the 'home root' ('C') down to 'Bb?'
     The following harmony suggests an 'F' triad -- with the Bass Player enjoying a 'Bb' note. In this scenario: 'Bb' sounds like 'Fa' -- and 'Bb' Lydian is the melodic terrain. We could refer to this 'harmonic shape' as 'The Melodic IV Chord' -- I call it the 'Harmonic Shape of Lydian.' 

     Before we move on to the third 'IV Chord Type' -- let's take a look at what can be understood 'within' the makeup of these first two 'Harmonic Shapes:'  

​
​




              Where's The One Chord?

     When any triad is assumed to be a 'V' Chord ('Root' sounds like 'So') -- we can use 'its' I Chord (a perfect fourth above) for melodic embellishment:

​


​
​     When any triad is assumed to be a 'IV' Chord ('Root' sounds like 'Fa') -- we can use 'its' I Chord (a perfect fifth above) for melodic embellishment:

​

The three harmonic shapes of Modal Jam Theory 'abandon' the I Chord (as a theoretical construct from the root of Ionian).

     When we are focused on a 'C' Triad (as the Tonic) - we think of 'C' as being the root of the 'Harmonic Shape of Mixolydian:' 'F/C.'  
​     When we are focused on the 'tighter' harmony of 'Cma7' (as the Tonic) - we think of 'C' as being the root of the 'Harmonic Shape of Lydian:' G/C.
​
​

           




                
                           The Minor IV Chord

     When 'Fa' (F) pivots to become 'So' -- a new 'Fa' is created that is one whole-step down from that 'Fa.' This suggests that any time we hear the progression of 'Fma' -- 'Ebma' -- it sounds like 'V' - 'IV' (double pivot). But what happens when we 'keep' the root of 'C' -- under this new IV Chord?
     The following harmony suggests an 'Eb' triad -- with the Bass Player enjoying a 'C' note. In this scenario: 'C' sounds like 'Re' -- and 'C' Dorian is the melodic terrain. We could refer to this 'harmonic shape' as 'The Minor IV Chord' -- I call it the 'Harmonic Shape of Dorian.'

​

​               



                
                        Three Harmonic Shapes

​

     Let's take a look at the three 'Harmonic Shapes' of Modal Jam Theory:

​

​     Even though we have 'declared' the 'Harmonic IV Chord' as the 'Harmonic Shape of Mixolydian' -- realize that its tones are those of the 'true 'IV' Triad of Ionian' ('F'). Of these three harmonic shapes -- the 'Harmonic Shape of Mixolydian' is the most 'flexible' - making it ideal for exploiting melody with modal triads.
     The following example suggests that it's not much of a stretch to hear 'F/C' as having the melodic terrain of 'F' Mixolydian ('C' Dorian)... and to my way of thinking -- It's also not much of a stretch to think of a II-V-I progression as a II-V-IV.
     Study the following II-V-I model well - with both ears and eyes. The ear's reaction to the harmonic overtone series results in a leap in mental logic. It is this 'leap' that musicians can learn to see... as well as they hear: 

​​