Since the release last month of "The SUPER 4" Shortbook™ and blogpost, I've subsequently come across a few additional interesting and potentially useful musical relationships between aspects of this "super" 4-note grouping, known technically as a tetratonic.
Specifically, I've been checking out the effect of expressing them in intervals of a minor 3rd, which divides the octave into four equal parts - forming the diminished cycle.
As mentioned, the results proved to be quite interesting - and musically useful to boot.
Dom7 13
Maj7#11
min6 9
Dom7 alt
min7b5.
After all, they're really just melodic expressions of time-honored piano voicings to begin with. Why should keyboard players have all the fun?!
In Ex. 1 below, a sequence made up of four identical tetratonic shapes descends in minor 3rds in bars #1 & 2. Each 4-note shape consists of a tritone and a Perfect 5th. This creates a neat, symmetrical, intervallic line which, after several repeats, resolves to a singular tetratonic in bars #3 & 4.
The chord choices, from the five listed above, are interesting in that, while attempting to create some type of ii-V7 movement, I realized that a line with the tetratonics ascending in minor 3rds (instead of descending, as it is here), would lend itself to a more traditional ii7b5 - V7alt (the ACE method).
To clarify that, and hopefully not to confuse; if we were to work backwards from the end of bar #2 to the beginning of bar #1 (creating an ascending line with exact same notes, retrograde or not), instead of B7 13 and F-7b5 in bar #2, we could have D#(Eb)-7b5 G#(Ab)7alt.
In bar #1, it would be A-7b5 D7alt.
In either case, the relationship between bars #1 & 2 remains a tritone.
Ex. 1
The first two measures are tritone substitutions for each other. Which led me to a startling discovery!
Bb-C-D-Eb-F-Gb-G-A, which is non other than a Bb Major BeBop Scale, aka Bb 6th/ Diminished Scale.
Are you startled yet? Logically, the same thing would be happening in bar # 2 - a tritone away: E-F#-G#-A-B-C-C#-D# = E 6th/ Diminished (BeBop) Scale.
The significance of this earth-shattering revelation, as far as I can tell, is in the ascending version of this sequence (described above the Ex. 1 graphic), whereas D#-7b5 G#7alt (bar #2) is the ii-V7 of C# min, the relative minor of E Maj. Likewise in bar #1; A-7b5 D7alt is the ii-V of G min - the relative minor of Bb Maj. Make sense?
Whew! I´m glad that´s out of the way!
Ex. 2 below again shows the same sequence - four SUPER 4 tetratonics (tritone & P5th) descending in minor 3rds - transposed and rhythmically broken up with triplets and rests. The chords, again chosen from the basic 5, have their roots ascending in min 3rds - in contrary motion to the line itself - before resolving V7-I7 to a Bb7 13 tonic dominant.
Can you tell which 6th / Diminished Scales are in play here?
(Answer: E & Bb, in bars #1 & 2 respectively - the reverse of Ex. 1.)
Ex. 2
The BeBop Scale equivalents here are C (bar #1) & F# (bar #2).
Ex. 3
The SUPER 4 tetratonic is a great little tool for the improviser - allowing for a leaner, meaner set of note choices.
Make it work for you!
B. Stern
the following Shortbooks™ break it down even further.
Available for immediate download!