Dominant seventh chord


Recall from lesson on building a context that we've defined a chord as being 3 or more distinct notes, usually played at the same time. (C and D are considered distinct, but C# and Db are not, nor are octaves of the same note).

Recall that chords come in two basic parts, a letter name (C, C#, etc.) also known as a root note (tonic, 1), and a descriptive part that abbreviates the name of the chord (is a short-hand for all the intervals of each distinct note from the root note).

Recall that an interval is the distance between two notes, and that we are using numbers (with accidentals) to describe these intervals.(ex. 5 = perfect fifth, etc.) For more info on intervals see the interval lesson. to convert letters to numbers and numbers to letters, see the link below (bottom of page) on transposition.

Recall, we've previously defined the following chords:
major = 1,3,5
minor (m)= 1,b3,5
diminished (o)= 1,b3,b5
power chord (5) = 1,5,8(1)

Now we shall define the dominant seventh chord as:
7 = 1,3,5,b7
Sometimes we write dominant seventh chords as dom7 or 7. (Ex. C7, Ddom7, etc.)

Here are some open 7 chords to get you started:
A7=X02023, B7=X21202, C7=X32310,
D7=XX0212, E7=020130, G7=320001.

We should note from our definition (7=1,3,5,b7) that a dominant seventh chord contains a major chord (major=1,3,5) within it.
We can think of a dominant seventh chord as a major chord with an added minor seventh note.

If we don't know how to play a 7 chord, we could substitute a major chord with the same root note in its place. We will no longer have the full flavor of the 7 chord, but the substitution should work.

We also note that a chord synonym for for I7 is biiiob6. In the key of F:
C7 = C,E,G,Bb = Eo/C

So you could use as a substitute for a 7 chord, a diminished chord a major third higher than the 7 chord. (you could substitute Eo for C7)

Recalling how the chromatic scale maps out on a fretboard in standard tuning ( see interval lesson). We can map out the 7 chord on the fretboard (shown here in F).

|-1|--|--|--|-3|--|--|-5|--|--|b7|--|-1|
|-5|--|--|b7|--|-1|--|--|--|-3|--|--|-5|
|--|-3|--|--|-5|--|--|b7|--|-1|--|--|--|
|b7|--|-1|--|--|--|-3|--|--|-5|--|--|--|
|--|--|-5|--|--|b7|--|-1|--|--|--|-3|--|
|-1|--|--|--|-3|--|--|-5|--|--|b7|--|-1|

We can cut this up into zones of one sort or another. In previous lessons, we've been looking at shapes based on octave patterns. (A-shape, E-shape, etc.). So below are the 5 shapes along with some voicings in TAB that go along with the shape. All of these are for F7. To change to to another 7 chord, we use the same process as for other moveable chords (barre chords, etc.).

F7 "E-shape"(root note on the 6th string)

|-1-|---|---|---|
|-5-|---|---|b7-|
|---|-3-|---|---|
|b7-|---|-1-|---|
|---|---|-5-|---|
|-1-|---|---|---|
  4

|--1-1-1-------1-1-1-1--|
|--4-1-4---1---1-1-4-4--|
|--2-2-2-2-2-2-2-2-2-2--|
|--3-1-1-1-1-1-1-1-3-3--|
|--3-3-3-3-----3-----3--|
|--1-1-1-1-1-1----------|

F7 "D-shape" (root note on the 4th string)

|---|---|-3-|---|
|---|b7-|---|-1-|
|---|---|-5-|---|
|-1-|---|---|---|
|-5-|---|---|b7-|
|---|---|-3-|---|
  6

|--5-5-5---5-5--|
|--4-4-6---6-4--|
|--5-5-5-5-5-5--|
|--3-3-3-3---3--|
|----3-6-6-6-3--|
|--------5---5--|

F7 "C-shape" (root note on the 5th string)

|-3-|---|---|-5-|
|---|-1-|---|---|
|-5-|---|---|b7-|
|---|---|-3-|---|
|---|b7-|---|-1-|
|-3-|---|---|-5-|
  8

|------8-5-8--|
|--6-6-6-6-6--|
|--8-8-8-5-8--|
|--7-7-7---7--|
|--8-8-8-6----|
|----8---5----|

F7 "A-shape" (root note on the 5th string)

|-5-|---|---|b7-|
|---|---|-3-|---|
|b7-|---|-1-|---|
|---|---|-5-|---|
|-1-|---|---|---|
|-5-|---|---|b7-|
 11

|--11-11-11--8--8-----------|
|--10-10-10-10-10-10-10-10--|
|--10-10-10--8--8--8-10--8--|
|--10-10-10-10-10-10-10-----|
|---8--8-----8--8--8-----8--|
|------8--------8----11-----|

F7 "G-shape" (root note on the 6th string)

|---|b7-|---|-1-|
|-3-|---|---|-5-|
|-1-|---|---|---|
|-5-|---|---|b7-|
|---|---|-3-|---|
|---|b7-|---|-1-|
 13
|-11-----------| |-10----13-----| |-10-10-10-----| |-10-13-13-13--| |-12-12-12-12--| |-13-13----13--|

Ok. So we can make many different voicings out of a given chord (many more than shown here). Choosing for ourselves just what voicing we're going to use to interpret a chord is one part of developing our own style.

Recall from our definition of a chord that we said they were 3 or more distinct notes (and their octaves) usually played at the same time.

I would like us to consider that last part of the definition, "usually played at the same time." In what instances aren't they played at the same time? let's briefly look at one and I'll discuss one in detail.

You could have a situation where your hand is holding down the whole chord at one time, but you are picking/strumming fewer notes than are contained in the chord at any one instant. Here's two examples:

1.) Complex strumming patterns:
So when you first learn to strum, it's downstrums through every string of the chord. And that gets boring real fast. So then you mix downstrums with upstrums, a little better. maybe you play a bass note and then strum. And this is an instant where you're not playing the whole chord. Maybe then you learn alternating bass strums (1-chord-5-chord, etc.), more moments where you're not playing the full chord. And your beginner's book probably stopped there. maybe you picked up a book on rhythm guitar and they included bass runs, damping, muting, choking, and it probably stopped after a couple of complex examples of this. But one technique that seems to not be mentioned in books (at least not the ones that i've seen so far), is to fret a chord on many strings, and alternate strumming the whole chord with strumming only a few strings of the held chord. This is often heard in funk music.
So just one example: take an E7 chord (E7=020130), and try hitting the 6th string twice, then strumming the whole chord up and down, then strumming just the top three strings up and down. Sounds better played faster. It should be noted that where you strum (in between the neck and bridge at what point) also has an effect on the tone. you might choose to strum the full chord at one spot, and the partial chord somewhere else.

2.) Arpeggios

Probably the most common way of hearing chords with notes not all played at once would be the playing of arpeggios.

Consider simple fingerpicking patterns such as P-I-M-A. (which would be using, in order, one at a time, the thumb,first,second, and third fingers of the picking hand) We could such a pattern with notes from a chord (here D7=XX0212) like this:

|--------2--|
|------1----|
|----2------|
|--0--------|
|-----------|
|-----------|

That would be one example of an arpeggio. We notice from above that when we get to seventh chords, we see more possibilities for note choices on a single string in a given position.

Here is another example of an arpeggio based on F7 (in E-shape, 1rst position) Compare shape with notes in TAB.

|-1-|---|---|---|
|-5-|---|---|b7-|
|---|-3-|---|---|
|b7-|---|-1-|---|
|---|---|-5-|---|
|-1-|---|---|---|
  4

|-----------------1----|
|-------------1-4------|
|-----------2----------|
|-------1-3------------|
|---0-3----------------|
|-1--------------------|

You need not play all the notes, nor play them in order or only once. Consider the following from the same chord, shape, etc.

|-1-5-1---------------|
|-------4-1-----------|
|-----------2---------|
|-------------1-3-----|
|---------------------|
|---------------------|

Or how about we create a fingerpicking pattern such as:

|--------1------------|
|-----------4---------|
|-----2---------------|
|--1------------------|
|-----3---------------|
|--1------------------|

Ok so we can play 7 chords several ways, but what do we do with them? Are there any general rules? (yes. Can we break them? you bet.)

CHORDS in CONTEXT

We often see 7 chords written in songs, but there is a way to understand why they pop up where they do? Usually.

Recall, that we harmonized the major scale to get the chords (triads):
I-ii-iii-IV-V-vi-viio (in the key of C: C-Dm-Em-F-G-Am-Bo)
and the seventh chords:
Imaj7-ii7-iii7-IVmaj7-V7-vi7-vii7b5 (in C: Cmaj7-Dm7-Em7-Fmaj7-G7-Am7-Bm7b5)

We can see here that the only chord in the major scale with a dominant 7th chord is the 5. Recall that the 5th note is referred to as the dominant note in the Roman Numeral System (see interval lesson). It is said that the dominant (V) chord is the most common chord (after the I). I don't know who keeps such statistics but that sounds right.

The movement from the dominant to the tonic chord (V-I) is called an "authentic cadence". A cadence is like a progression. Consider the movement of individual notes from chord (V) to chord (I). In the key of C, V=(G= G,B,D), I=(C= C,E,G). We see that the note G can stay where it is (no movement), the B note is a half-step away from C (small movement). So we expect a smooth transition between a V chord and a I chord. What about a V7 chord? in C, V7=(G7= G,B,D,F). We've already looked at the 1rst 3 notes. F is a half-step away from E (small movement), which is even smaller movement than the D to E. We often think of the V7 chord as being a leading chord (it wants to resolve/lead you to the I chord).

Where else does the dom 7 chord turn up?
Without getting into the modes of these scale systems as well, we find dom7 chords in the natural minor, harmonic minor, and melodic minor scales (also in their modes).

In the natural minor (minor scale, or aeolian mode), the dom7 is the bVII7 (in the key of Am: bVII7= (G7= G,B,D,F), Am= (A,C,E)). All note movements are within a whole-step. The progression bVII-i (or V-vi) is called a "deceptive cadence."

In the harmonic minor scale, the dom7 chord is the V7. And in fact, the harmonic minor scale was altered to facilitate having that chord in that position. In the key of Am: V7= (E7= E.G#,B,D), and i = (Am= A,C,E).

In the melodic minor scale, the dom7 chord occurs twice, as bIII7 and IV7.

So let's consider some progressions.

One of the most common progressions is I-IV-V, which comes out of the major scale. It's often heard in country, folk, blues, rock 9as well as others). We could use V7 instead of V (and this is often done) giving I-IV-V7 (in the key of C: C-F-G7).

The most common progression in jazz is ii7-V7 or ii7-V7-I. You could say this comes out of the major scale, but it's equally considered a Dorian progression (the Dorian mode is the 2nd mode of the major scale). So you could see ii7-V7 as I7-IV7 (as a dorian progression). You should note that i7-IV7 is also a progression that comes out of the melodic minor (jazz minor) scale. (In the key of C: ii7-V7-I = Dm7-G7-C) (In D-Dorian: i7-IV7 = Dm7-G7), (in A melodic minor = i7-IV7 = Am7-D7).

The V7 chord leads well to a I or i chord ( a major or minor chord a p4 above it), so often a dom7 chord is substituted at the appropriate place (a p4 below the target chord, or a p5 above it). These are called secondary dominants in theory texts.

So maybe you want a chord to lead to the V7. A perfect 4th below that would be the 2, so we could substitute a II7 chord for the 2 chord. this is often called the "V of the V", and in theory texts you'll see it written as V7/V. It's often heard in ragtime, and jazz. For instance the progression I-ii7-V7-I (from the major scale) could be changed to I-II7-V7-I (key of C: I-II7-V7-I = C-D7-G7-C).

We can continue to find the V of the ii (or V of the V of the V), notated in theory texts as V/ii. We could see this as VI7 (in the key of C: VI7= A7). So consider the following progression (in C):
C-G/B-A7-D7-G7-C.

We could keep going, such as
C-E7-A7-D7-G7-C.
The III7 (E7) being the V of VI (written V7/vi).

In fact we could go through all 12 keys/notes in a circle of 5ths:
C-F7-Bb7-Eb7-Ab7-Db7-Gb7-B7-E7-A7-D7-G7-C.

Often in blues, you hear the I-IV-V progression completely in dom7 chords:
I7-IV7-V7
(In C: I7-IV7-V7 = C7-F7-G7).

Try throwing that into a 12-bar blues progression:
C7-C7-C7-C7
F7-F7-C7-C7
G7-F7-C7-G7

We often use V-I or V-i to modulate (change between) keys. So to go from key of C to key of Eb, we could use
C-Bb7-Eb
or from key of C to key of Dm, we could use
C-A7-Dm.

And as an illustration of harmonic minor, and diatonic circle of 4ths, consider:
Am-Dm-G7-Cmaj7-Fmaj7-Bm7b5-E7-Am.

Everything is in Am (natural minor) except the V7 (E7), which would point to A harmonic minor.

INVERSIONS and CHORD SYNONYMS

we can invert 4 note chords, just like 3 note chords. For our purposes, we wish to know when a particular bass note is or is not in our chord, and when we can substitute 7 chords for other chords without having added or subtracted any distinct notes from our previous chord (what chords can be seen as different spellings of the dom7 chord?) We will use G7 as our example to be inverted and renamed.

G7= G,B,D,F (root position, 1 is in the bass)

1rst inversion, 3rd is in the bass
G7/B = B,D,F,G, what B chord is this?
B,D,F,G = 1,b3,b5,b6
we could call this Bob6.

2nd inversion, 5th is in the bass
G7/D= D,F,G,B, what D chord is this?
D,F,G,B = 1,b3,4,6
We could call this Dm6(4), or Dm(6)add4, or Dm6add4(no5)

3rd inversion, 7th in the bass.
G7/F = F,G,B,D, which F chord is this?
F,G,B,D = 1,2,#4,6
you have options, such as
F6/9#11(no3,no5), Fo6sus2, F6(#4)sus2

So for a iob6, we could substitute bVI7

for i6(4), i(6)add4, i6add4(no5) we could substitute IV7.

and for I6/9#11(no3,no5), io6sus2, I6(#4)sus2 we could substitute II7.

Speaking of substitutions, the dominant note (5) of the major scale as a functional position probably sees more substitutions of extended and altered chords on that spot than any other note (functionally). Some extensions and alterations often found on the dom7 chord are listed below for the intermediate/advanced student to work through and explore:

7 = 1,3,5,b7
9 = 1,3,5,b7,9
11 = 1,3,5,b7,9,11
13 = 1,3,5,b7,9,11,13
7sus2 = 1,2,5,b7
7sus4 = 1,4,5,b7
6/7 = 1,3,5,6,b7
7/11 = 1,3,5,b7,11
7/#11 = 1,3,5,b7,#11
7#5 = 1,3,#5,b7
7b5 = 1,3,b5,b7
7#9 = 1,3,5,b7,#9
7b9 = 1,3,5,b7,b9
9#5 = 1,3,#5,b7,9
9b5 = 1,3,b5,b7,9
7#9#5 = 1,3,#5,b7,#9
7#9b5 = 1,3,b5,b7,#9
7b9#5 = 1,3,#5,b7,b9
7b9b5 = 1,3,b5,b7,b9
11#9 = 1,3,5,b7,#9,11
11b9 = 1,3,5,b7,b9,11
11#5 = 1,3,#5,b7,9,11
11b5 = 1,3,b5,b7,9,11
11#9#5 = 1,3,#5,b7,#9,11
11#9b5 = 1,3,b5,b7,#9,11
11b9#5 = 1,3,#5,b7,b9,11
11b9b5 = 1,3,b5,b7,b9,11

And the list goes on...
The 11th could be #11. We could continue go on to 13th chords. the third could be suspended, we could omit notes, etc.
we often see these things in jazz heads. If you don't know how to play one of these chords, there's a good chance you could get away with substituting a 7 for it (of course, you'll lose part of the flavor, but in a jam...). it might be helpful to learn some 7 shapes without 5's in them (so it doesn't clash when substituted for a dominant chord with an altered 5).

Here are some in F (F7(no5))
F7 = 1X12XX (E-shape, root on 6th string)
F7 = XX3X45 (D-shape, root on 4th string)
F7 = X8786X (C-shape, root on 5th string)
F7 = X8X8 10 X (A-shape, root on 5th string)
F7 = XXX10 10 11 (G-shape, root on 3rd string)
F7 = 13 12 13XXX (G-shape, root on 6th string)

Peace,
Chris Roberts


How do I change all those numbers to letters (for notes, chords, etc.)? Here's a transposition chart simianmoon.com/snglstringtheory/guitar/8theory3.html

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Last updated January 1, 2003.
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