Every chord type is defined by its characteristic combination of intervals. But there is no obligatory order of these intervals. A major chord for example consists of its root (1), major 3rd (3) and a perfect 5th (5). No matter if the sequence is 1 3 5 or for example 1 5 3 or 3 5 1, it is still the same major chord.
Every possible sequence of intervals of a chord
is a voicing of that chord
It's also very common that intervals appear more than once, like in the following voicings.
You may know the term inversion of a chord, but inversions do not cover all possible combinations of sequences. Especially when it comes to chords with more than just three different tones.
Let's start with basic major chords
Voicings 1 3 5 1 and 1 5 1 3
This may remind you of the "CAGED system" ...a kind of childish way to explain the following things in a way that makes people believe they can get around the theory ;-)
The theory is actually even easier (and much more useful), because with just a little understanding of intervals we can break down those 5 basic chords (C,A,G,E and D) to only two(!) categories of chord shapes:
Chords starting off with intervals 1 3 5 1:
Chords starting off with intervals 1 5 1 3:
See also lection on basic major chords
These shapes are also the basis for all the following voicings of 7th chords, where we just replace the second root by a 7th or skip one or another string. But before we tackle the 7th chords, I want to consolidate your understanding of pure major chord shapes.
- I will move all chord shapes up a few frets. You can see that you can move each of those shapes freely along the fretboard to get other major chords.
- I end up with just three different keys (A, D, G) in this example, but each chord shown in two different voicings now.
Voicing 1 3 5 1 (...)
Voicing 1 5 1 3 (...)
1 5 1 3... shapes as E,A and D before
Voicing with smaller intervals like 1 3 5 1 are considered as closed voicings
those with larger intervals (and therefore bigger distance between lowest and highest note) are called open voicings
Voicings for 7th chords
We can take the two categories of major chord voicings (1351... and 1513...) now and replace the second root (1) by a 7th.
- 1 3 5 1 → 1 3 5 7
- 1 5 1 3 → 1 5 7 3
- 1 5 1 3 5 → 1 5 7 3 5 or 1 _ 7 3 5
Remember, we don't distinguish between maj7, 7 or dim7. To describe a voicing it's enough to universally write a "7".
The playability of different voicings may differ significantly. While easier to play on the piano, closed voicings of some chord types can be too hard to play on the guitar. So let's start with open voicings.