Music in Theory; Functionality of Rootless Chords

This is the third post in a series of specific posts where I just talk about my passion for music theory, different exercises and things that i've thought up that may shed light on something or somethings that musicians are either struggling with or else it's a completely new subject to them or opens a completely different door to them musically.
If I can inspire my fellow musicians as much as they inspire me, then I can die happy.
so here goes.
Lesson 3 in the aptly named: Music in Theory

Functionality of Rootless Chords

Voicing?

Ok so, before I go diving head first into everything about rootless chords, there is one small term that I want to shed light on so that no one gets lost or confused and that is the term 'voicing' or 'chord voicing' and what is meant by it.
If we take a simple triad chord for example, C major, nice and simple. we know the notes of the C major chord are the root, C, the major third, E and the perfect 5th, G.
The term chord voicing refers to how those notes are arranged, which notes are at the bottom, which are doubled up etc.
For Example; CGCE, GCE, CGECEG are all different voicings of the C Major chord.

With that basic shit out of the way lets bang on to craziness. Mwuhahaha.

Rootless Chord Voicings

Rootless Chord voicings, sometimes referred to as Bill Evans chord voicings since he was a pioneer of the inventive interpretation of harmony that gave way for rootless chords, are effectively a chord without the root.
The End.
Bye - Bye.

I'm kidding. There is slightly more to it than that. Primarily, a Rootless chord will be a variation or an alteration in flavor of a chord, Usually a chord with a 7th degree in it, such as a Dominant 7, Major 7 or Minor 7, as opposed to a triad.

Bill Evans, being absolutely rad with his mad harmony

The root is removed from the chord, and an additional degree is added, usually the 9th, 11th or 13th.
A simple example would be, say we have a G min7 chord. The notes of which are G, Bb, D and F.
I want to remove the root and add the 9th of G min7; which then gives me Bb, D, F and A, which is our rootless chord.

Rootless chords arent particularly jarring in sound, some inversions of the chord will be more than others, but with the lack of a root, the chord does have a sense of ominousness or ambiguity to it.

If you are good with your chord theory you probably would have noticed that Bb, D, F and A are also the notes of Bb maj7.
likewise, if we start with  a G min7 b5 chord, the notes Bb, Db, F and A are also common to a Bb min maj7 chord.
Therefore, by removing the root, you are allowing the chord to evolve into something else momentarily, which serves as variation for the tonal quality of the chord you are playing.

The Key is harmony.
When the Bass is playing the root of a G min7, and the guitarist plays Bb, D, F and A it can sound bomb as fuck.

Other uses of the rootless chord rule is of course for soloing and improvisation. you may choose to apply a rootless voicing over a 251 progression.

I prepared an example of a Funk lick played over a rootless G dominant 9 chord which you can find below:

https://soundcloud.com/craig-mccomish/a-study-in-audiosynthesis-rootless-funk-over-g9-chord

The ambiguity of the chord voicing comes across in the note choice, in this case using the Major 3rd, flat 7th, major 9th and Perfect 5th. (it also includes an odd passing note which is the major 6th).

If you'd like to check out better uses of rootless chord voicings, my best recommendation would be listening to Bill Evans' work.
Sunday at the Village Vanguard (1961) by the Bill Evans is renowned for being one of the best live jazz albums of all time, and features the late great Scott LaFaro on Bass duties.