Music theory for banjoheads, pt. 5, On Beyond Zebra (9ths, 11ths, and 13ths, alterations...)

"On Beyond Zebra" is the name of my favorite Dr. Seuss book from when I was a kid. In the beginning a little boy, one Conrad Cornelius O'Donald O'Dell, is standing on a chair writing the alphabet on a blackboard and telling a bigger kid what each letter stands for. The other kid is like huh, is that all you got?

"I'm telling you this 'cause you're one of my friends

My alphabet starts where your alphabet ends!"

Spoiler alert: You use the letter "yuzz" to spell yuzz-a-ma-tuzz.

We won't be imagining new worlds or Seussian zoology here, but my "what-you-need-to-know-to-play-in-my band" series usually ends with 7th chords, and we need to press ahead a bit further. So...

Ninth chords

In part 2 (intervals) we identified the interval of a ninth as a second plus an octave (2 + 8 = ......9!). The reason why it's a ninth chord and not a "second chord" - even though we're talking about the same note above the root - is this: The "ninth" in the chord is arrived at by stacking another third on the "root-third-fifth-seventh" ladder. So a "ninth chord" is a five-note chord, R 3 5 7 9.

Obviously you can't play all five notes on the banjo, nor should you feel obligated to. Most of the time, the three notes you want to be sure to have in your voicing are the 3rd, 7th, and of course the 9th. Here are the spelling of some ninth chords built on C:

Cmaj9 - C E G B D (maj7 + 9th interval)

C9 - C E G Bb D (dominant 7 + 9th)(the "James Brown" chord)

Cm9 - C Eb G Bb D (min7 + 9)

I'll be following each section with some 3- and 4-note ideas for playing these; here are some 9ths:

There is such a thing as an "added 9" chord, these days frequently referred to as a "2." This is where there's a ninth (or indeed, a 2nd) in the chord that hasn't been arrived at by stacking thirds. It's an added note chord. So C add9 or C2 is CDEG

Something to always keep in mind...

With any of these extended harmonies you are free to just use the 7th chord.

In other words, at any time you may ignore any and all chord tones above the 7th without changing the harmonic sense. And it is sometimes a good idea to keep it simple if you are sharing the stand with another player who is using a lot of extended voicings. 

Eleventh chords

Where a min7 or min7b5 is involved, you will use a P11, so:

Cm11 - C Eb G Bb D F

Cm7b5 - C Eb Gb Bb x F (ninths are a little awkward in this chord)

Anything with a major third, you want to use a #11.

Cmaj9#11 - C E G B D F# 

C7#11 - C E G Bb D F#

Look at the top four notes of Cmaj9#11 C E G B D F#.  Gmaj7, yes? So you can use that to voice an extended Cmaj7, so long as there's a big fat C in the bass (or otherwise implied). Don't go memorizing all those combinations, that's one of the things you can work out in the trenches!

The designation "b5" is not the same as a #11! A #11 implies the presence of a 5th in the chord, while "b5" means the 5th itself has been changed. C7b5 = C E Gb Bb.

A P11 in one of those major chords replaces the third and is then called a "suspended fourth" or just "sus four."

C7sus4 - C F G Bb 

C9sus4 - C F G Bb D (both are interchangeable)

There is a plain sus4 triad:

Csus4 or C4 - CFG

which usually resolves to major, like in the intro to "Tommy." In the original version, it happens at 0:18. https://youtu.be/UFrDpx7zLtA?list=RDUFrDpx7zLtA

When 11th or 13th chords are indicated in the chart, the 11th or 13th is usually a melody note, so again, if you don't think you need to play it you can leave it out. As a matter of fact, if you don't think you need to play it please do leave it out!!

Thirteenth chords

Here's the one you're most likely to see:

 C13 - C E G Bb D x A (if anyone wants the #11 they'll write it C13#11)

Of course, root-3-5-7-9-11-13 takes in every scale tone, so again, the 

third, seventh, and thirteenth

are the only ones you need to make sure to have in there.

The next section applies to dominant seventh chords, which come in two basic families: the ones we've looked at, i.e., regular old 9ths and 13ths: and

Altered 5ths, 9ths and 13ths

or just "altered dominants." Pretty much any of these will be interchangeable in all their forms - G7#9b5, G7b9#5, G7#9b13...Sometimes you can just write "G7alt." For your purposes right now, moving the fifth and/or ninth in either direction will give it an "altered" feel.  Soon I'll go into "tritone substitution," which will give you a bit of extra insight on these kinds of chords. For now, notice how  dominant 7ths at the distance of a tritone from one another start looking alike.

The #9 chord deserves a special mention. Here's G7#9 - G B D F Bb. Yes the sharp-nine is technically A#, but it's usually thought of as a minor third. In your voicing of the chord you need at least the 3rd, 7th, and #9. The #9 should be voiced higher than the third. Along with a ninth, a very useful chord for one-chord funk jams.

The best way to learn to use these kinds of chords is to learn a lot of tunes as chord-melody solos. Stay tuned.