Online Bass Instruction with Rusty Springfield
Chords 101

It is essential that we, as bassists, have a good working knowledge of chord structures and their respective sounds. Once you play some of these chords, you will realize that you've heard many of them before, but perhaps didn't know what they were called. There are five basic chord groups with which we will begin our study. Each is characterized by it's own combination of chord tones (root, third, fifth, seventh, etc.) It would be most helpful for you to play these chords on a keyboard, so that you can familiarize yourself with each chord's unique sound. Chord symbols, and their variations, are discussed in detail later. Though learning the "formula" for these chord groups requires a bit of memorization, the process need not be overly tedious. Try memorizing one chord form each day.

This knowledge will pay off on the gig. Believe it!

The five basic groups are:
1. Triads
2. Major seventh chords
3. Dominant seventh chords
4. Minor seventh chords
5. Diminished seventh chords.
Triads

A triad is, as its name implies, a three note chord. It consists of a root, third, and a fifth. It can be major or minor, depending on whether its third is "natural" or "flatted." It is a very simple sounding chord, and is used extensively in pop, rock, folk music, hymns, etc. The first chords every aspiring guitarist learns to play are triads. In the key of C, a major triad would simply be labeled "C," and would contain a root (C), major third (E), and a "perfect" fifth (G). A minor triad differs only in the use of a flatted third (Eb). Note: A "major" third interval is two whole steps above the root. A "minor" third is a whole step and a half step above the root. The only difference between a major and a minor chord is the placement of the third!

Note that, in practice, it is very common to hear a triad with its third on the bottom instead of the root. A "C" triad with it's third in the bass would be labeled C/E and referred to as "C over E." This is a very effective chord to place in between a root chord which moves to its "fourth" chord, such as a C triad moving to an F triad. You've no doubt heard progressions like this a million times without realizing it.

Also, a "sixth" interval can be added to a basic triad forming a "6th chord." A C6 chord contains C-E-G-A.
Major Seventh Chords

The addition of a "natural" or "major" seventh interval (one half step below the root) to a major triad gives us a major seventh chord. It is used in many pop tunes, jazz standards, and "jacuzzi jazz" tunes.

A C Maj7 chord contains C-E-G-B. (Major 3rd and natural 7th.)
Dominant Seventh Chords

A "dominant" seventh chord, also just (sometimes confusingly) called a "seventh" chord, is identical to a "major" seventh chord except that it uses a lowered or "flatted" seventh interval. It has a bluesier sound, and is heard in blues, folk jazz and funk contexts.
A C7 chord contains C-E-G-Bb. (Major 3rd and flatted 7th.)
Minor Seventh Chords

Minor seventh chords are heard in pop, folk, and jazz tunes. Take a "dominant" seventh chord and lower the third. Voila! You now are the proud owner of a minor seventh chord.

A C-7 chord contains C-Eb-G-Bb. (Flatted 3rd and flatted 7th.)
Diminished Seventh Chords

A frequently misunderstood chord is the "diminished" chord. The terms diminished chord and diminished seventh chord are used interchangeably. They refer to the same chord. A diminished chord is a minor chord containing a flatted fifth and a "double flatted" seventh. (Just so you don't experience synaptic failure trying to figure out a "double flatted" seventh, think of it as a sixth instead.) Diminished chords are used as "passing" chords between two "static" chords to provide movement in the harmony. If you analyze the intervals in a diminished chord, you will find that its entire structure is built upon minor thirds. With a bit more analyzing, you will discover that there are actually only three diminished chords. At every third interval up, the chord repeats itself!

eg: A Cdim7 contains: C-Eb-Gb-A.
An Ebdim7 contains: Eb-Gb-A-C.
A Gbdim7 contains: Gb-A-C-Eb.
An Adim7 contains: A-C-Eb-Gb.

Now do the same with a Dbdim7 and a Ddim7. Get the idea? All you're doing is changing the order of the notes!

F.Y.I. ...
It should be mentioned that one other common usage of diminished chord tones is their solo adaptability in outlining dominant seventh, flatted ninth chords.

eg: A7(b9) contains A-C#-E-G-Bb. A diminished chord played from the third would yield C#-E-G-Bb, which is a C# diminished chord. In other words, if you are soloing and come across a dominant seventh chord with a flatted ninth, you could outline a diminished chord, starting with the third interval of the dominant chord, because both chords contain the same intervals.

Basically, this concept just gives you a handy way to think about altered dominant chords. You will find that, in practice, dominant chords allow the soloist to include just about every interval there is, if properly placed and emphasized. Your ears will tell you if your note choice is a good one or not. Miles Davis was a master of harmonic overlay. He would frequently play (and hold) a flatted ninth or other altered interval on top of a dominant chord vamp. This gave the chord that "dark" sound he so loved.
Go to the next lesson: Suspended Chords