the iv Chord - part two

Orchestral Bass Movement

By D.C. Large

In part one, we were searching for a harmonic/compositional justification for the ubiquitous iv (four minor) chord.

In part two I wanted to back up a bit to illustrate a distinctive attribute of the whole chord pattern.

As mentioned before, the iv chord is normally found in this progression;

I I7 IV iv

example...

C C7 F Fm6

The progression is normally played using specific tones in the bass...

I/1 I/b7 IV/3 iv/b3

example...

C/C C/Bb F/A Fm6/Ab

This produces an interesting descending bass line.

Orchestral Bass Movement

Its fascinating to me that not a century after the church organ keyboard had become fully chromatic, and practice instruments became available (small stringed clavichords) that composition had leapt so far. It’s as if remarkable minds (Pachelbell - Bach) were poised to take advantage of the full harmonic compass. Diatonic music was fully explored and then expanded, with the introduction of extreme tension/resolution with secondary dominants, faux modulation, and diminished harmony, all within a relatively short span of time.

Part of this revolution was the implementation of orchestral bass movement.

Originating as “inversions” to facilitate movement on the keyboard, pronounced to achieve an effect, and reenforced in ensemble by other instruments (bass viols).

Harmonic Justification

In short, any tone of the chord may serve as it’s bass tone.

Example: Pachebell’s Canon in D

An early, and perhaps the most famous example. later reflected in countless compositions.

? “Air” - Johann Sebastian Bach

? “Whiter Shade of Pale” - Procol Harem

? “In My Life” - Beatles

? “For No One” - Beatles

? “Piano Man” - Billy Joel

? “Welcome to the Black Parade” - My Chemical Romance

? “One Day More” - from Les Misérables

A skeleton pattern of eight diatonic chords, over eight measures, with arpeggios and melodic inventions superimposed.

D A Bm  F#m

G D G   A

analysis...

I  V    vi    iii

IV   I    IV   V

Not much on its face, what made it memorable is the descending bass line...  

D/D  A/C#  Bm/B  F#m/A

G/G  D/F#   G/G   A/A

analysis...

I/8  V/7    vi/6    iii/5

IV/4   I/3    IV/4   V/5

Note

These issues are discussed in depth in 

Harmony & Composition vol 1

Harmony & Composition vol 2

Harmony & Composition vol 3

by DC Large