Help on naming two chords

Can someone tell me the names of these two chords. These are the first two chords from James Brown “Sex Machine,” I think?

A bonus would be if you can explain why they are named what they are (I’ve got a basic understanding of intervals).


Hi Daniel,
The Gb9 (G flat 9) chord contains the notes Gb, Bb, Db, Fb and Ab. It is produced by taking the 1 (root), 3, 5, b7 and 9 of the Gb Major scale. The 9th note of the scale (Ab) is the same as the 2nd note, but we refer to it as a 9, as this implies that the chord is a dominant 7 chord (1, 3, 5, 7) with a 9 included.

The 9th chord is a very popular guitar chord in Jazz, Funk and Blues. It is in many ways, the go-to ‘funk’ chord. The 9th chord can often be substituted for a dominant 7 chord.

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You can use Ultimate Guitar to find chords of songs, then clicking on any of the chord diagrams, you can scroll through alternative ways of playing.

(I had to transpose this one to get the key you are playing in)

I use these to help find suitable chords to play when I know the original artist doesn’t use, say, a standard barre chord but a variation of it.

Handy for finding ‘cheating’ ways of playing the same chord too…

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Thanks much. That makes sense although I’m going to study it. I’ve just started to understand chord extension. With Sex Machine it’s definitely blues/funk. I like the sound. So now trying to wrap my head around chord construction.
Thanks again!


If you like that early 70s JB sound, check out Curtis Mayfield from the same era. There a lot of similar funkiness going on in both sound and rhythm. Loved that stuff back in the day !


I will do that. Thanks for the suggestions. I’m always open to new ideas as well as suggestion regarding bands/artists to check out.

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The 1st is a Gb9 and the 2nd is a Gb13. Both are extensions of a dominant 7 type chord.
Important … The note labelled as E on the 3rd string has been incorrectly named in both diagrams. That note, when based around the Gb major scale and Gb rooted chords, should be referred to as Fb. This is because of the rules of the major scale and the need to use each alphabetic letter name once only. That note is the flattened 7th scale degree - making the chords into dominant chords.

See below.

It is probably easier to see the correct note names and the derivation of these extended chords by building from a simple C-shape major chord along with reading from a C major scale.

See below.

For the C7 I have omitted the 5th scale degree. A major chord triad is built as 1, 3, 5 so a dominant 7 chord formula is 1, 3, 5, b7. However, when played in the C-shape on just 4 strings (as shown in the diagram below), the 5th is omitted. This does not effect the type of chord it is. When chords are extended, some notes can be omitted in this way.

Here are some common chord shapes of the type you ask about - all extensions of the basic C-shape major and all (apart from the basic major chord) classed as dominant chords.

C-shape major chord:

C-shape dominant 7 chord:

C-shape 7#9 (the Hendrix chord):

C-shape 9 chord:

C-shape 13 chord:

I hope that helps.

Cheers :smiley:

| Richard | JustinGuitar Approved Teacher, Official Guide & Moderator

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Actually I’m looking at Gb on a Circle of Fifths and it makes sense. Ab is both the 2nd and the 9th in the key of Gb (Your diagram give another way of looking at it in intervals) .
I’m at the stage right now where I learn things and then forget them, then run into a situation where the skills would be useful (like determining those chord shapes), and reviewing and relearning again. In my case I don’t shun repetition - repetition is my friend.

I just played the Gb Major scale and, yep, I see the 9th and the 13th now as well as the flattened 7th making the a Gb7 dominate chord which the Gb9 and Gb13 is constructed from.

I guess I’ll add this to my practice time today under “Theory.”
Thanks much!

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I L-O-V-E the circle of fifths.
If you have a few hours spare I wrote an entire topic on it here: The Circle of Fifths - where does it come from, where does it go?

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Thanks. I’ve bookmarked it for later review.
Currently I’ve decide to go back to the beginning and start Justin Guitar at Grade 1. As the course addresses theory, I’ll eventually get back to the Circle of Fifths and will review this.